Evo and Proud

The Sub-Saharan African Dental Complex

2012-01-28T12:26:00.005-05:00

Map of Nigeria, showing the location of the Iwo Eleru rock shelter and the Iwo Eleru skulls. (Harvati et al., 2011)

Sub-Saharan Africans have an unusual complex of dental features:

[…] compared to other world populations, Africans south of the Sahara Desert are distinct dentally — especially in their expression of nine high- and two low-frequency morphological features. This suite of traits was termed the “Sub-Saharan African Dental Complex” (SSADC); it includes the world’s highest occurrences of Bushman canine, two-rooted UP1, UM1 Carabelli’s trait, three-rooted UM2, LM2 Y-groove, LM1 cusp 7, LP1 Tom’s root, two-rooted LM2, and UM3 presence, and among the lowest occurrences of UI1 double shoveling and UM1 enamel extension. (Irish, 2011)

The two low-frequency traits appear to be “derived.” They seem to have developed in sub-Saharan Africa after modern humans began to spread to other continents. The other traits, however, are ancestral:

[…] the same nine high-frequency traits are also ubiquitous in the dentitions of extinct hominids and many extinct and extant non-human primates

[…] The presence and, indeed, prevalence (see next section), of high-frequency Sub-Saharan dental traits in fossil and recent hominoids—some of which are probably direct ancestors of modern humans, suggests they have been around for a long time. (Irish, 1998, pp. 87-88)

In addition to these traits, Irish (1998) mentions a low-frequency trait that seems likewise ancestral and specific to sub-Saharan Africans:

A final ancestral feature found with some regularity in Sub-Saharan Africans, relative to other modern groups, is polydontia. Numerous cases of extra incisors, third premolars, and fourth molars have been noted […] In one study (Watters, 1962) the incidence reached 2.5-3% in several hundred west Africans; many of the extra teeth were fully formed and erupted. “Typical” mammals exhibit three incisors and four premolars (Jordan et al., 1992). Polydontia is also found in living non-human primates […] (Irish, 1998, p. 88)

Why are these ancestral traits much more common in sub-Saharan Africans than in other humans? There are several possible reasons. One is that non-Africans began as a small founder group and thus lost much of the dental variability that still characterizes Africans. Another reason might be that natural selection favored new forms of dentition outside Africa, perhaps as a response to new food sources or new ways of preparing food.

But there’s a third possible reason: archaic admixture. Just as modern humans mixed to some extent with Neanderthals in Europe and Denisovans in Asia, perhaps there was also mixture with archaic hominins in Africa, and perhaps this admixture introduced archaic dental features into present-day Africans.

But how could present-day Africans have archaic admixture? If modern humans originated in Africa, wouldn’t they have encountered archaic humans only in Europe and Asia?

Well, at first, modern humans did not occupy all of Africa. They were initially a small population somewhere in East Africa. Then, around 80,000 years ago, this population began to expand northward and eventually into Eurasia (Watson et al., 1997). Meanwhile, the same expansion was taking modern humans westward and southward into other parts of Africa.

Just whom exactly did these modern humans encounter during their expansion within Africa? Initially, they probably met hominins who looked the same but still lacked some of the mental rewiring that gave modern humans a competitive edge. These “almost-moderns” account for about 13% of the current sub-Saharan gene pool and may have been related to the Skhul-Qafzeh hominins who occupied the Middle East 120,000 to 80,000 years ago (Watson et al., 1997).

As modern humans spread further west and south within Africa, they encountered much more archaic hominins, and perhaps even lingering Homo erectus groups. About 2% of the modern African genome comes from an archaic population that split from ancestral modern humans some 700,000 years ago. This admixture is dated to about 35,000 years ago and may have occurred in Central Africa, since the level of admixture is highest in pygmy groups from that region (Hammer et al., 2011).

A more tangible sign of admixture is visible in a skull retrieved from the Iwo Eleru rock shelter, in southwestern Nigeria, and dated to approximately 16,300 BP:

Our analysis indicates that Iwo Eleru possesses neurocranial morphology intermediate in shape between archaic hominins (Neanderthals and Homo erectus) and modern humans. This morphology is outside the range of modern human variability in the PCA and CVA analyses, and is most similar to that shown by LPA individuals from Africa and the early anatomically modern specimens from Skhul and Qafzeh.

[… ] the transition to anatomical modernity in Africa was more complicated than previously thought, with late survival of “archaic” features and possibly deep population substructure in Africa during this time. (Harvati et al., 2011)

Then there is the Broken Hill skull, found near Kabwe, Zambia and dated to 110,000 BP (Bada et al., 1974). It looks for all the world like a Homo erectus. Textbooks generally try to raise it to Homo sapiens status or argue for an earlier dating. Recently, a late dating has been confirmed by Stringer (2011).

Interestingly, when Irish (2011) compared dentitions from west, central, east, and south Africa, ranging in age from the late Pleistocene to the mid-1950s, the early Holocene Kenyans and Tanzanians were the sample that had the fewest ancestral traits of the Sub-Saharan African Dental Complex (SSADC). In other words, the SSADC seems to have been least present in the “homeland” of modern humans (East Africa) and more present farther west and south.

Given the high level of archaic admixture in sub-Saharan Africans, we may have to revise downwards the estimate of 1 to 4% Neanderthal admixture in Eurasians. Yes, Eurasians are closer than sub-Saharan Africans to the Neanderthal genome. But is this discrepancy solely due to Neanderthal admixture in Eurasians? Could it also be due to Sub-Saharan Africans becoming further removed from the Neanderthal genome through admixture with other archaic groups?

The past may be a stranger country than previously thought. When farming villages began to form in the Middle East, there may still have been archaic hominins roaming over parts of western and southern Africa.

References

Bada, J.L., R.A. Schroeder, R. Protsch, & R. Berger. (1974). Concordance of Collagen-Based Radiocarbon and Aspartic-Acid Racemization Ages, Proceedings of the National Academy of Sciences (USA), 71, 914-917.

Hammer, M.F., A.E. Woerner, F.L. Mendez, J.C. Watkins, and J.D. Wall. (2011). Genetic evidence for archaic admixture in Africa, Proceedings of the National Academy of Science (USA), 108, 15123-15128, www.pnas.org/cgi/doi/10.1073/pnas.1109300108

Irish, J.D. (2011). Afridonty: the “Sub-Saharan African Dental Complex” revisited, American Journal of Physical Anthropology, 144(supp. 52), 174

Irish, J.D. (1998). Ancestral dental traits in recent Sub-Saharan Africans and the origins of modern humans, Journal of Human Evolution, 34, 81-98.

Harvati, K., C. Stringer, R. Grün, M. Aubert, P. Allsworth-Jones, C.A. Folorunso. (2011). The Later Stone Age Calvaria from Iwo Eleru, Nigeria: Morphology and Chronology. PLoS ONE 6(9): e24024. doi:10.1371/journal.pone.0024024
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0024024

Stringer, C. (2011). The chronological and evolutionary position of the Broken Hill cranium. American Journal of Physical Anthropology, 144(supp. 52), 287

Watson, E., P. Forster, M. Richards, and H-J. Bandelt. (1997). Mitochondrial footprints of human expansions in Africa, American Journal of Human Genetics, 61, 691-704.

Do classes become castes?

2012-01-21T16:35:00.003-05:00

Relative frequencies of surnames of the rich and the poor (common criminals) 1236-1858. In England, there seems to have been much downward mobility among descendants of the medieval rich and some upward mobility among descendants of the medieval poor (Clark, 2010).
H/T to Jason Malloy

Henry Harpending (2012) argues that a meritocracy would become a caste society in a few generations:

Consider free meritocracy in a two-class system, meaning that for each generation anyone in the lower class who has greater merit than someone in the upper class immediately swaps class with them. Mating then occurs at random within class.

[…] Class mobility after the first generation is 30% while after four generations it has declined to 10% and continues to decline after that. The average merit in the two classes is about -1SD in the lower and +1SD in the upper on the original scale, corresponding to IQs of 85 and 115.

[…] after four generations, about 70% of the variance is between classes.

This model, however, contradicts what Clark (2009a) found in his historical study of surnames and social class in England. He first collected rare English surnames that were exclusive in the year 1600 to the rich (as represented by wealthy testators) or to the poor (as represented by common criminals). He then went forward in time to the year 1851 and determined the occupational profile of the same rare surnames:

How do the descendants of these two groups look in terms of socioeconomic status by 1851? Surprisingly there seems to be almost complete regression to the mean.

Between 1600 and 1851, there was apparently great downward mobility among descendants of the rich and modest upward mobility among descendants of the poor. Clark (2010) subsequently found that this regression held true for the entire period stretching from 1236 to 1858 (see above chart).

Why does this outcome diverge so much from the theoretical outcome described above? One reason is the assumption that marriage takes place only within each social class. Yet assortative mating is only a tendency, and exceptions are numerous. In post-medieval England, a widower would likely take a second wife of lower social status because of his disadvantaged position on the marriage market, given the care required for his existing children. It was also accepted for an upper-class man to marry a woman of lower rank, on the condition that she be beautiful. This phenomenon was noted by Darwin:

Many persons are convinced, as it appears to me with justice, that our aristocracy, including under this term all wealthy families in which primogeniture has long prevailed, from having chosen during many generations from all classes the more beautiful women as their wives, have become handsomer, according to the European standard, than the middle classes; yet the middle classes are placed under equally favourable conditions of life for the perfect development of the body. (Darwin, 1936 [1888], p. 892)

Another reason is downward mobility. In England, the upper and middle classes were reproductively more successful than the lower class until the late 19th century. But higher-class families could offer their children only a limited number of occupational slots. A certain proportion thus had to emigrate or move down the social ladder. The lower class was thereby continually replenished by the demographic overflow of the upper and middle classes.

Finally, the word “merit” has different meanings in different contexts. It is never just IQ. In post-medieval England, merit meant a mix of “middle-class” values: thrift, self-control, future time orientation, and rejection of violence as a way to settle disputes (Clark, 2007; Clark, 2009a; Clark, 2009b). In other societies, merit may involve a different mix of predispositions and personality traits, such as ruthlessness and willingness to use violence.

Yet caste societies do exist. How do they come about? The main precondition seems to be not only the existence of social classes, but also a monopoly on certain occupations by each class. In such circumstances, downwardly mobile individuals cannot compete with the existing lower class, since the latter’s livelihood remains off-limits.

Take Japan. That country had a social evolution similar to England’s, i.e., gradual demographic expansion of the middle class and, correspondingly, gradual demographic replacement of the lower classes by downwardly mobile individuals. But the lowest class, the Burakumin, survived because it had a monopoly on occupations that involved taking life or handling dead bodies (e.g., leather working, butchery, undertaking, etc.). The Burakumin thus survive as a remnant of the majority Japanese population that existed several centuries ago.

Stigmatized castes, like the Burakumin, may provide a window into a population’s evolutionary past. Such groups cannot participate in the gene-culture co-evolution of the majority population. Nor do they have much leeway for their own gene-culture co-evolution, since they are rigorously confined to a few occupations.

References

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World. Princeton and Oxford: Princeton University Press.

Clark, G. (2009a). The indicted and the wealthy: surnames, reproductive success, genetic selection and social class in pre-industrial England. http://www.econ.ucdavis.edu/faculty/gclark/Farewell%20to%20Alms/Clark%20-Surnames.pdf

Clark, G. (2009b). The domestication of Man: The social implications of Darwin. ArtefaCTos 2(1): 64-80.

Clark, G. (2010). Regression to mediocrity? Surnames and social mobility in England, 1200-2009
http://www.econ.ucdavis.edu/faculty/gclark/papers/Ruling%20Class%20-%20EJS%20version.pdf

Darwin, C. (1936) [1888]. The Descent of Man and Selection in relation to Sex. reprint of 2nd ed., The Modern Library, New York: Random House.

Harpending, H. (2012). Class, Caste, and Genes, West Hunter, January 13
http://westhunt.wordpress.com/2012/01/13/class-caste-and-genes/

African Americans and recent evolution

2012-01-14T16:52:00.003-05:00

Fulani woman, Nigeria. Source.
African Americans aren’t just sub-Saharan Africans with European admixture. There has also been admixture from Amerindian peoples and from groups partly of North African origin, like the Fulani.

Have African Americans evolved since they first came to North America? The question may seem strange. Doesn’t evolution happen over millions of years? The first slaves disembarked in the future United States back in 1619 and the last ones arrived (illegally) in the 1850s. That’s about three centuries. How could any population evolve over so short a time?

Yet natural selection can cause significant change in as little as eight generations, at least in nonhuman species. In humans, it has altered at least 7% of the genome over the last 40 thousand years, and most of that change has happened over the last 10 thousand years (Hawks et al., 2007).

Jin et al. (2011) argue that African Americans have changed genetically over the last three centuries, not only through European admixture but also because of natural selection. First, many black slaves died during their passage from Africa to the New World. The survivors, already a select group, faced a new environment in colonial America. They had to adapt to new challenges in their struggle for existence, such as new pathogens, new social structures, and new means of subsistence.

To identify these effects of natural selection, Jin et al. (2011) used two methods on a large sample of African Americans (5,210 individuals). They first looked at various genomic regions to see whether the degree of European admixture was higher or lower than the admixture for the genome as a whole, estimated at 21.61%. Such deviations would be “signals” of natural selection favoring certain genetic variants at the expense of others.

The second method involved comparing the African component of the African American genome with the genomes of present-day sub-Saharan African populations—in proportion to their respective contributions to the African American gene pool.

And the results? Some genomic regions did deviate from the level of 21.61% European admixture. Many of them were associated with diseases, like prostate cancer and hypertension, that are more common among African Americans than among Euro Americans. Alleles that protect against malaria were also less frequent than would be predicted by European admixture. This is evidence that natural selection has been eliminating alleles that are less necessary in North America.

These results seem expectable. Too expectable, in fact. Yes, prostate cancer occurs more often in African Americans than in Africans, but this difference is due to underreporting and shorter life expectancy in Africa. Keep in mind that prostate cancer tends to be diagnosed late in life (Ogunbiyi & Shittu, 1999; Osegbe, 1997).

There are other grounds for skepticism. The deviations from overall European admixture were small, less than 2.6%. Admittedly, the sample size was large, so sampling error couldn’t be responsible. But there may have been other sources of error.

One of them concerns the estimated European admixture of 21.61%. This figure is consistent with previous estimates and is probably the best one available. But the degree of admixture varies among African Americans, especially by social class and by geographic region.

The authors also oversimplify their model when they describe African Americans as sub-Saharan Africans with European admixture. There has also been Amerindian admixture, as noted by Myrdal (1944, p. 124):

Indians were held as slaves in some of the American colonies while Negro slaves were being imported. Equality of social status between Indians and Negroes favored intermingling. The whites had little interest in hindering it. As the number of Negro slaves increased, the Indians slaves gradually disappeared into the larger Negro population. Whole tribes of Indians became untraceably lost in the Negro population of the South. […] Twenty-seven and three-tenths per cent of the Negro sample of 1,551 individuals examined by Herskovits claimed some Indian ancestry.

The authors state that they excluded African American individuals who had more than 2% Native American/East Asian ancestry, but such exclusion is at best approximate. And what about the many individuals with 1-2% Amerindian ancestry?

Another wild card is North African admixture. The Atlantic slave trade involved some populations that were partly of Arab/Berber descent, such as the Fulani (also known as Fulbe or Peul. The hotel maid who gave DSK a BJ was a Fulani). To some degree, North African admixture would resemble European admixture. To some degree, it would have its own characteristics.

Admittedly, these other admixtures were relatively small. But one doesn’t need a big factor to explain a deviation of two percent or so.

Ideas for future research

I’d like to see more research on recent evolution among African Americans, in particular on the possibility of gene-culture co-evolution. One cultural determinant of genetic change might be Christianity, specifically the way it has structured family life, turned men into active fathers, and created a strict rules-based culture.

Briefly put, I’d like answers to the following questions:

1. Was natural increase higher among church-going African Americans than among non-churchgoers? (because of a higher rate of family formation, stronger male involvement in the family, lower rate of infant mortality, etc.)

2. Did churchgoers have a different psychological profile than non-churchgoers? In other words, were non-churchgoers disproportionately made up of individuals who had trouble complying with a rules-based culture?

3. Did the higher natural increase of churchgoers, together with their psychological profile, lead to an evolutionary process similar to what Clark (2007) has described for England? (i.e., gradual demographic replacement of impulsive, present-oriented individuals with disciplined, future-oriented individuals).

4. Did this process abort in the 1960s with the decline in church life among African Americans?

References

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World, Princeton University Press, Princeton and Oxford.

Hawks J, Wang ET, Cochran GM, Harpending HC, Moyzis RK (2007). Recent acceleration of human adaptive evolution. Proc Natl Acad Sci USA, 104, 20753-20758.

Jin, W., S. Xu, H. Wang, Y. Yu, Y. Shen, B. Wu, & L. Jin (2011). Genome-wide detection of natural selection in African Americans pre-and post-admixture, Genome Research

Myrdal, G. (1944). An American Dilemma, Harper & Row, New York

Ogunbiyi, J. and Shittu, O. (1999). Increased incidence of prostate cancer in Nigerians. Journal of the National Medical Association, 3, 159-164.

Osegbe, D. (1997). Prostate cancer in Nigerians: facts and non-facts. Journal of Urology, 157, 1340.

Were Neanderthals furry?

2012-01-07T12:11:00.031-05:00

What did the Neanderthals look like? Source
Hard to tell, since we know so little about their soft tissues. But they probably had fur.

Were the Neanderthals as furry as bears? The question was raised by one of my readers, and I’ll try to reply at length in this post.

There are three lines of argument:

Lack of tailored clothing

Neanderthal sites show no evidence of tools for making tailored clothing. There are only hide scrapers, which might have been used to make blankets or ponchos. This is in contrast to Upper Paleolithic (modern human) sites, which have an abundance of eyed bone needles and bone awls (Hoffecker, 2002, pp. 107, 109, 135, 252). Moreover, microwear analysis of Neanderthal hide scrapers shows that they were used only for the initial phases of hide preparation, and not for the more advanced phases of clothing production (Hoffecker, 2002, p. 107).

The counter-argument is that some human groups, notably the Yaghan of Tierra del Fuego, have lived in sub-arctic environments with little clothing.

Human body louse

The human body louse (which lives in clothing) seems to have diverged from the human head louse with the advent of modern humans. This dating is based on a comparison of the two louse genomes:

The results indicate greater diversity in African than non-African lice, suggesting an African origin of human lice. A molecular clock analysis indicates that body lice originated not more than about 72,000 ± 42,000 years ago; the mtDNA sequences also indicate a demographic expansion of body lice that correlates with the spread of modern humans out of Africa. These results suggest that clothing was a surprisingly recent innovation in human evolution.(Kittler et al., 2003)

A more recent analysis places the origin of body lice at 83,000 to 170,000 years ago (Toups et al, 2011). The authors conclude: “Our estimate for the origin of clothing use suggests that one of the technologies necessary for successful dispersal into colder climates was already available to AMH prior to their emergence out of Africa.”

There is nonetheless some controversy over the phylogenetic status of these two kinds of louse. Light et al. (2008) argue that there is far too much genetic overlap between them and that they cannot be considered “genetically distinct evolutionary units.” This point has been reiterated by Li et al. (2010):

While being phenotypically and physiologically different, human head and body lice are indistinguishable based on mitochondrial and nuclear genes. As protein-coding genes are too conserved to provide significant genetic diversity, we performed strain-typing of a large collection of human head and body lice using variable intergenic spacer sequences. Ninety-seven human lice were classified into ninety-six genotypes based on four intergenic spacer sequences. Genotypic and phylogenetic analyses using these sequences suggested that human head and body lice are still indistinguishable. We hypothesized that the phenotypic and physiological differences between human head and body lice are controlled by very limited mutations.

This is a recurring problem when one examines two species or subspecies that have recently diverged from each other. The only genes that have diverged are those whose variants clearly differ in adaptive value between the two environmental settings—in this case, head hair and clothing. It is only with time, and reproductive isolation, that differences will develop at other gene loci.

In the meantime, lice—like humans—exhibit the apparent contradiction of distinct phenotypic differences co-existing with very fuzzy genetic differences.

Finger bone ridges

A third reason is given by Cochran and Harpending (2009):

We don’t yet know for sure, but it seems likely that, as part of their adaptation to cold, Neanderthals were furry. Chimpanzees have ridges on their finger bones that stem from the way that they clutch their mother’s fur as infants. Modern humans don’t have these ridges, but Neanderthals do.

References

Cochran, G. & H. Harpending (2009). Neanderthals Steve Sailer’s iSteve Blog, January 10, 2009
http://isteve.blogspot.com/2009/01/neanderthals.html

Hoffecker, J.F. (2002). Desolate Landscapes. Ice-Age Settlement in Eastern Europe. New Brunswick: Rutgers University Press.

Kittler, R., M. Kayser, & M. Stoneking. (2003). Molecular Evolution of Pediculus humanus and the Origin of Clothing, Current Biology, 13, 1414-1417.

Li, W., G. Ortiz, P-E. Fournier, G. Gimenez, D.L. Reed, B. Pittendrigh, D. Raoult. (2010) Genotyping of Human Lice Suggests Multiple Emergences of Body Lice from Local Head Louse Populations. PLoS Negl Trop Dis 4(3): e641.

Light, J.E.,M.A. Toups, & D.L. Reed. (2008). What’s in a name: The taxonomic status of human head and body lice, Molecular Phylogenetics and Evolution, 47, 1203-1216.

Toups, M.A., A. Kitchen, J.E. Light, & D.L. Reed. (2011). Origin of Clothing Lice Indicates Early Clothing Use by Anatomically Modern Humans in Africa, Molecular Biology and Evolution, 28, 29-32.

A few of my themes for 2012

2011-12-31T14:04:00.024-05:00

Yakuzas (Japanese mafia). The largest Yakuza syndicate is over 70% Burakumin. Source

Here are a few themes I wish to write about during 2012:

Archaic admixture: A wild goose chase?

With the discovery that Europeans and Asians are 1 to 4% Neanderthal, there has been a rush to learn more. What genes are involved? Does this admixture explain why Eurasians are, well, hot stuff?

A few words of caution. The estimate of 1 to 4% is based on comparison of the Neanderthal genome with the modern Eurasian genome and the modern sub-Saharan African genome (Green et al., 2010). Neanderthals appear to be genetically closer to modern Eurasians than they are to modern sub-Saharan Africans. This increased closeness is therefore a measure of Neanderthal admixture in modern Eurasians. Right?

Well, not necessarily. It may also be a measure of non-Neanderthal admixture in modern sub-Saharan Africans. We now know that about 2% of the modern sub-Saharan African genome comes from a population that split from ancestral modern humans some 700,000 years ago (Hammer et al., 2011). Another 13% comes from archaics who were much closer to modern humans and probably related to the Skhul-Qafzeh hominins of the Middle East (Watson et al., 1997).

The figure of 1 to 4% Neanderthal admixture in modern Eurasians will thus have to be revised downward, just as our estimate of archaic admixture in modern sub-Saharans will have to be revised upward. This point has been made by Dienekes:

It is no longer tenable to propose that Eurasians are shifted towards Neandertals only because of Neandertal admixture: in fact some of the shift may be due to Africans being shifted away from Neandertals because of admixture with archaic African hominins.

However great or small Neanderthal admixture may be, can it explain why modern Eurasians are “hot stuff”? Doubtful. It’s true that both populations had to adapt to arctic environments, but they did so in very different ways. Neanderthals adapted to the cold through their morphology: thick body fat and dense fur. Modern Eurasians adapted by making tailored clothing and building insulated shelters.

Please don’t get me wrong. If you’re doing research on Neanderthal admixture, I wish you the best of luck. Perhaps you’ll find a thing or two. But don’t get your hopes up.

Whither North Korea?

Whenever an authoritarian leader dies, the door is opened to change, often radical change. The new leader is less able to command authority, and the chain of command itself is called into question at all levels. Pent-up pressure for change can finally be released. This was the case after the deaths of Franco in 1975, Mao Zedong in 1976, and Brezhnev in 1982. Here in my home province, it was the death of Duplessis in 1959 that ushered in the end of Quebec as a conservative Catholic society.

Will we see the same in North Korea? Will the death of Kim Jong Il lead to liberalization and, ultimately, reunification with South Korea?

Yes and no. North Korea will pursue its transition to a market economy. And this process is already making the population more independent-minded. As an observer in Pyongyang recently noted:

The women who daily set out their wares on the streets do so in defiance of police prohibitions. This is one of the clearest indications of the erosion of the regime’s control over its people. (The author observed many others, such as the men who openly smoked under “No Smoking” signs, the peasants who simply ignored the traffic police and trundled their carts across intersections, and the people who—under the very eyes of the police—sat on the escalators in the Metro despite stern signs prohibiting this.) (Everard, 2011)

Private markets are also creating new spaces of social interaction that are independent of the State, and this trend will be assisted by the spread of cellphones and the strengthening of economic and social relations with China—itself a much more liberal society.

Finally, North Korea will drop all pretence of international socialism. This might seem to be just a matter of words—North Korea has long been a de facto nationalist regime—but semantics are important in the way people construct their perceived reality.

But, no, reunification is not in the cards, if only because the Chinese are adamantly opposed. There was a time in the 1990s when they were open to this idea. With reunification, U.S. troops would leave and Korea would become a more neutral country. It is now clear, however, that reunification has produced no such outcome in Germany. The Cold War may be over, but the U.S. still wants to have troops in mainland Eurasia, apparently as part of its geopolitical strategy.

So for now at least the Chinese will try to strengthen North Korea as a friendly buffer state. To this end, they will prod Pyongyang to pursue economic reforms and shed its pariah image, particularly by dismantling its nuclear program. In exchange, the Chinese may offer the protection of their own nuclear umbrella, as well as full membership in the Shanghai Cooperation Organisation (SCO).

It’s also unlikely that liberalization will lead to North Korea becoming more Westernized and Americanized. By “liberalization,” I mean the right of people to live their lives according to their own values—and not those imposed by the State or by a globalist elite. Hence, the Arab Spring has brought the triumph of Islamist political parties who promise to introduce stricter adherence to Shariah law. This has been a surprise to Western observers, but it should not have been.

The Burakumin

Although Japanese society is often seen as being very homogeneous, it does have a distinct class called the Burakumin who were officially outcastes until 1871 and are still widely looked down upon. They seem to descend from Japanese who held stigmatized occupations that involved the taking of life or contact with dead bodies, like butchery, leather making, and preparation of corpses for burial. Today, despite many remedial efforts, an academic gap persists between the Burakumin and other Japanese:

According to research on Buraku pupil/students' scholastic ability conducted in the post-war period, nearly 1 standard deviation difference in achievement scores was found between Burakumin and non-Burakumin pupil/students regardless of when and where the research was conducted. This meta-analysis on Buraku pupil/students' scholastic ability leads us to conclude that the relative difference in scholastic achievements between the Burakumin and non-Burakumin pupil/student has been maintained to a considerable degree through the post-war period. (BLHRRI, 1997)

In 2012, I will try to shed new light on this question by applying Greg Clark’s model. Clark (2007) argued that the English gene pool in 1800 was quite different from what it had been only a few centuries earlier. Over the years, the English middle class had expanded demographically and, through downward mobility, had largely replaced the English lower classes. I will suggest that Japan followed a similar evolution but with an interesting twist. As outcastes with a monopoly on certain occupations, the Burakumin were spared this demographic replacement. They may thus represent the Japanese population as it existed several centuries ago.

References

BLHRRI (1997). Practice of Dowa Education Today, Buraku Liberation and Human Rights Institute.
http://blhrri.org/blhrri_e/dowaeducation/de_0006.htm

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World, Princeton University Press, Princeton and Oxford.

Dienekes. (2011). Neanderthal admixture. Why I remain skeptical, December 19, 2011.
http://dienekes.blogspot.com/2011/12/neandertal-admixture-why-i-remain.html

Everard, J. (2011). The markets of Pyongyang, Korea Economic Institute, Academic Paper Series, 6(1), 1-7.
http://www.keia.org/publication/markets-pyongyang

Green, R.E., J. Krause, A.W. Briggs, T. Maricic, U. Stenzel, M. Kircher, et al. (2010). A draft sequence of the Neandertal genome, Science, 328, 710-722.
http://www.sciencemag.org/cgi/reprint/328/5979/710.pdf

Hammer, M.F., A.E. Woerner, F.L. Mendez, J.C. Watkins, and J.D. Wall. (2011). Genetic evidence for archaic admixture in Africa, Proceedings of the National Academy of Science (USA), early edition, www.pnas.org/cgi/doi/10.1073/pnas.1109300108

Watson, E., P. Forster, M. Richards, and H-J. Bandelt. (1997). Mitochondrial footprints of human expansions in Africa, American Journal of Human Genetics, 61, 691-704.

2012. A year of turbulence?

2011-12-17T12:10:00.005-05:00

Child making Nike shoes (source). Western business now has access to labor under conditions not seen since the days of Charles Dickens.

My predictions from last year:

It won’t be such a bad year. Stock markets will reach record highs and pundits will say we’ve entered a sustained boom. For many people, life will never again be so good as it will be this year.

The main worry will be price rises for many commodities. With a return to even modest rates of economic growth, demand will outstrip supply in several areas. Talk of “peak oil” will be joined by concerns over “peak food” and “peak water.” Serious water shortages will hit the American southwest and southeast.

Well, the stock markets have not reached record highs. And there have been no serious water shortages, largely because of an unusually wet winter.

But food prices have been rising ominously. It was this factor that triggered the “Arab Spring” and is now fueling discontent in Russia. Also, for a lot of people—especially our elites—life has never been so good. We are into an economic recovery, of sorts.

How long will the recovery last? Perhaps another twenty years if it were a normal one. But it isn’t. The last recession was not allowed to finish its job of purging the economy. A lot of corporate flab was spared the axe, and dysfunctional attitudes toward debt are still common, particularly among consumers. In addition, the recovery is heavily dependent on government spending and consumer debt, and there is no indication that the economy is ready to go “cold turkey.” We may need more and more of the same stimulus just to maintain sluggish growth.

This debt crisis comes on top of a looming commodity crisis. Prices for fuel, food, housing, and other basics are being pushed up by the new buying power of Asian consumers and by immigration to North America and Western Europe. Can supply be increased to meet the rising demand? Yes, of course. Don’t worry. Everything will be fine—say the business interests that profit from this spike in demand.

Finally, we are facing a globalization crisis. On the one hand, jobs are being outsourced to lower-wage countries. On the other, lower-wage labor is being insourced. The result? A steady downward leveling of incomes throughout the Western World, except for the very rich. The latter now have access to labor under conditions not seen since the days of Charles Dickens.

The current recovery might nonetheless go on indefinitely. The Japanese, for instance, have kept their economy afloat for the past two decades by piling up massive debt. But they are just one society, and it’s one with a strong sense of social cohesion. In contrast, the Western World is very fractious, as seen by the bickering within the European Union. These social and political divisions will probably abort the recovery long before the possibilities for debt financing and money printing have been completely exhausted. And so much the better.

If I have to make a prediction for 2012, it will be that the recovery will continue—on life support, so to speak—but will run into increasing social turbulence. The ‘Arab spring’ will start to play out in the Western World as the elites begin to lose their legitimacy. This process is already under way in Europe, and we may see a domino effect where change in one country facilitates change in other countries.

My research interests

There have been some developments in my areas of research interest.

Skin color and face recognition

Natural selection tends to hardwire recognition of objects that regularly appear in our visual environment. One such object is the human face. As shown by Zhu et al. (2009) through a twin study, the ability to recognize faces is innate and not learned. This heritability is further shown by the two extremes of prosopagnosics and “super-recognizers.” The former cannot recognize faces better than any other object, whereas the latter have exceptional face recognition ability (Russell, Chatterjee, & Nakayama, in press; Russell, Duchaine, & Nakayama, 2009).

The American psychologist Richard Russell has recently shown that face recognition equally uses face shape and facial skin color:

Shape and pigmentation cues were used in roughly equal measure by people with very good and very bad face recognition ability. […] People who are good at recognizing faces are good at using both shape and pigmentation cues to do so; people who are bad at recognizing faces are bad at using both shape and pigmentation cues to do so (Russell, Chatterjee, & Nakayama, in press).

This mental processing of skin color seems to take place in a lower-level module whose output then feeds into the face-recognition module.

Neural circuits related to face recognition ability must use both shape and pigmentation information about equally. This supports the idea that these circuits represent facial appearance by pooling lower-level patterns of shape and reflectance into combinations that include both types of information (Jiang, et al., 2006). Further, this is consistent with the notion that the location of the Fusiform Face Area is midway along the shape–reflectance gradient in ventral cortex (Cant & Goodale, 2011) because the region integrates these two kinds of cues to visually process faces. (Russell, Chatterjee, & Nakayama, in press)

Dumouchel et al. (2010) have likewise concluded that face shape and “skin properties” are the main clues for face recognition, even more so than the relative distances of facial features from each other.

Why does skin color matter so much for face recognition? Didn’t our ancestors evolve in a context where people interacted only with their own kind or with neighboring groups of similar appearance? Yes, but there was another source of variation in skin color—gender and age. Women and young infants are paler, having less melanin and hemoglobin in their skin. Men, in contrast, are ruddier and browner.

We are thus innately sensitive to differences in skin color, but this sensitivity didn’t evolve in response to ethnic differences. It evolved in response to much smaller gender and age differences (Frost, 2010; Frost, 2011; van den Berghe & Frost, 1986).

At present, two research teams have the means and motivation to pursue this line of research: Richard Russell’s team at Gettysburg College and Frédéric Gosselin’s team at the Université de Montréal. We’ll probably see more findings by both teams over the next year.

The puzzle of European hair and eye colors

European populations have an unusually broad palette of hair and eye colors. This diversity doesn’t have a common genetic cause. It is due to a proliferation of alleles at two separate genes: MC1R for hair color and OCA2 for eye color. This proliferation did not come about through relaxation of selection for dark skin as ancestral Europeans moved into higher latitudes. Most of the new alleles have little or no affect on skin color, and in any case the timeframe is too narrow for this evolutionary scenario.

A likelier cause is sexual selection, which favors bright or novel colors that catch the attention of potential mates. If sexual selection is strong enough, a polymorphism of color variants may develop. A new color appears through mutation and, depending on its brightness or novelty, steadily rises in frequency until it is as common as the established color. Over time, these variants will increase in number. Humans have the potential for this kind of frequency-dependent sexual selection, e.g., darker-haired women are sexually preferred to the extent that they are less common. Such selection is consistent with the high number of alleles for hair color and eye color in European populations, the high ratio of nonsynonymous to synonymous variants among these alleles, and the relatively short time over which this hair and eye color diversity developed.

Sexual selection occurs when too many of one sex must compete for too few of the other. Among early modern humans, such imbalances resulted from (1) polygyny (to the degree that women could provide for themselves and their children without male assistance) and/or (2) higher mortality among men than among women (to the degree that men covered longer distances while hunting or changing camp). Wherever the polygyny rate was low and male mortality high, the result was strong sexual selection of women. Such selection was particularly strong on continental steppe-tundra, where men had to provide almost all of the food by hunting migratory game animals over long distances. Although this type of environment is now fragmentary, it covered until 10,000 years ago a much larger territory that matches the current range of European hair and eye color diversity (Frost, 2006).

This hypothesis would predict some degree of sex linkage among European alleles for hair and eye color, since the sexual selection was acting on women. Over time, there would have arisen alleles that produce non-black hair and non-brown eyes more so in women than in men, and these alleles would have gradually replaced their non-sex-linked counterparts. This process should not have gone very far, though, because of the narrow timeframe.

This prediction is borne out by a twin study on the genetics of hair color. Shekar et al. (2008) found that the women had lighter hair on average than the men and a higher proportion of red hair. Hair color was also more diverse in the women than in the men:

Females had, on average, lighter hair, on the A650t scale, than males.

[…] The correlation within brother–sister twin pairs was significantly lower than the correlation within brother–brother and sister–sister dizygotic twin pairs (P ≈ 0.01). This suggests that there may be qualitative differences in the genetic influences on the A650t index between sexes.

[…] Additive genetic influences explain 55% and 58% of variation in the A650t index within females and males, respectively. The additive genetic influence on the A650t index in males was, predominantly, qualitatively different from those that influence the index in females.

[…] Females had, on average, redder hair (P < 0.00001) and greater variation in R index scores (P _ 0.001) than males.

The sexual selection hypothesis would also predict that this evolutionary change took place over a relatively short time, specifically the last ice age 25,000 to 10,000 years ago and well after the entry of modern humans into Europe some 35,000 to 40,000 years ago. Is this prediction supported by evidence?

At present, no one is trying to date the diversification of European hair and eye colors.
The closest research effort would be the work by Norton and Hammer (2007) showing that Europeans became white-skinned long after their entry into Europe. Heather Norton is now trying to get a firm date on this phenotypic change.

References

Dupuis-Roy, N., I. Fortin, D. Fiset, and F. Gosselin. (2009). Uncovering gender discrimination cues in a realistic setting. Journal of Vision, 9(2), 10, 1–8.
http://journalofvision.org/9/2/10/, doi:10.1167/9.2.10.

Frost (2011). Hue and luminosity of human skin: a visual cue for gender recognition and other mental tasks, Human Ethology Bulletin, 26(2), 25-34.

http://media.anthro.univie.ac.at/ISHE/index.php/bulletin/bulletin-contents

Frost, P. (2010). Femmes claires, hommes foncés. Les racines oubliées du colorisme, Quebec City: Presses de l’Université Laval.

Frost, P. (2006). European hair and eye color - A case of frequency-dependent sexual selection? Evolution and Human Behavior, 27, 85-103 http://www.sciencedirect.com/science/journal/10905138

Norton, H.L. & M.F. Hammer (2007) Sequence variation in the pigmentation candidate gene SLC24A5 and evidence for independent evolution of light skin in European and East Asian populations, Program of the 77th Annual Meeting of the American Association of Physical Anthropologists, p. 179.

Russell, R., G. Chatterjee, and K. Nakayama. (In press) Developmental prosopagnosia and super-recognition: no special role for surface reflectance processing. Neuropsychologia

Russell, R., B. Duchaine, and K. Nakayama. (2009). Super-recognizers: People with extraordinary face recognition ability. Psychonomic Bulletin & Review, 16(2), 252-257.

Shekar, S.N., D.L. Duffy, T. Frudakis, G.W. Montgomery, M.R. James, R.A. Sturm, & N.G. Martin (2008). Spectrophotometric methods for quantifying pigmentation in human hair—Influence of MC1R genotype and environment, Photochemistry and Photobiology, 84, 719–726.

Taschereau-Dumouchel, V., B. Rossion, P.G. Schyns, and F. Gosselin. (2010). Interattribute Distances do not Represent the Identity of Real World Faces, Front Psychol, 1, 159.

van den Berghe, P. L. & P. Frost. (1986). Skin color preference, sexual dimorphism, and sexual selection: A case of gene-culture co-evolution? Ethnic and Racial Studies, 9, 87-113.

Zhu, Q., Y. Song, S. Hu, X. Li, M. Tian, Z. Zhen, Q. Dong, N. Kanwisher, and J. Liu. (2009). Heritability of the specific cognitive ability of face perception, Current Biology, 20, 137-142.

Suicide and Inuit youth

2011-12-10T10:45:00.004-05:00

Canadian suicide rates (per 100,000 people): Inuit, First Nations, all Canadians. Source

From Alaska to Greenland, young Inuit have unusually high rates of suicide, attempted suicide, and suicidal ideation. According to a 1972 survey of Inuit 15 to 24 years old from northern Quebec, 28% of the males and 25% of the females had attempted suicide (Kirmayer et al., 1998). Before the 1970s, suicide was rare among Inuit youth. Today, it has reached epidemic proportions.

Public authorities have responded largely by targeting those factors, like alcohol and drug abuse, that make it easier to go from thinking about suicide to actually doing it. While these efforts are having some success, there still remains the problem of suicidal ideation.

Why do so many Inuit youth contemplate suicide? Kirmayer et al. (1998) point to a prevailing sense of uselessness:

Inuit youth are confronted with the values of an individualistic, consumption-oriented society through mass media but have few opportunities to achieve the life-style portrayed. The result may be a sense of frustration, limited options, and difficulty imagining an optimistic future. This may extend to an impaired sense of self-continuity that contributes to attempted suicide.

Dufour (1994) argues that Inuit society has a long tradition of people ending their lives when they feel they have become useless. In the past, however, this kind of suicide involved only the elderly:

Suicide in early Inuit society was viewed positively when the individual had become a burden for the group. “Senilicide” in particular was deemed to be acceptable and appropriate. Its pattern: a usually elderly person motivated by illness, helplessness, bereavement, dependence on the group, famine, or resource shortage who would decide after consulting family members who sometimes could be called upon to assist. In contemporary Inuit society, the elderly no longer commit suicide. The young people do.

TV and video present young Inuit with an affluent lifestyle that is unattainable for all but a few. Meanwhile, school presents learning goals and standards of behavior that are likewise difficult to attain, especially for boys. By postponing adulthood in order to extend the learning process, school also has the unintended effect of humiliating Inuit youth. In another age, they were treated as young adults, often being parents in their own right. Today, they are just “children.”

Many young Inuit thus perceive themselves as being socially useless. And this self-perception is triggering suicidal ideation.

Such ideation may seem irrational from an individualistic Western standpoint. You cannot make your life better by ending it. Yet it is less irrational from the standpoint of one’s kin group, especially in a context of limited resources. Such was the case with elderly Inuit who would choose death so as not to burden the younger members of their band, such people being close relatives for the most part.

In such a context, natural selection—specifically kin selection—might have favored suicide as a response to perceived uselessness. Such selection is possible. Suicidal ideation is significantly heritable and seems to be inherited as a specific behavioral response:

Suicidal behavior is highly familial, and on the basis of twin and adoption studies, heritable as well. Both completed and attempted suicide form part of the clinical phenotype that is familially transmitted, as rates of suicide attempt are elevated in the family members of suicide completers, and completion rates are elevated in the family members of attempters. A family history of suicidal behavior is associated with suicidal behavior in the proband, even after adjusting for presence of psychiatric disorders in the proband and family, indicating transmission of attempt that is distinct from family transmission of psychiatric disorder. (Brent & Mann, 2005)

According to a twin study using American subjects, suicidal ideation has 36% heritability and suicide attempt 17% heritability (Fu et al., 2002).

De Catanzaro (1991, 1995) has argued that suicidal ideation has evolved as a response to a situation where an individual has become a burden to immediate kin. In studies of the general public and high-risk groups (elderly and psychiatric patients), he found that the strongest correlate of suicidal ideation was burdensomeness to family and, for males, lack of heterosexual activity. As Buss (1999, p. 94) concludes: “If a person is a burden to his or her family, for example, then the kin’s reproduction, and hence the person’s own fitness might suffer as a result of his or her survival.”

The threshold for suicidal ideation may be lower in some human populations than in others, depending on one’s risk of becoming a serious burden on kinfolk. This risk is high in Arctic hunting bands because their members are almost entirely close kin and because their nomadic lifestyle limits food storage for lean times. When food is scarce, who eats and who doesn’t? The question is especially difficult because close kin are involved. The easiest solution, in terms of keeping the peace and maintaining group cohesion, is one where the burdensome individual voluntarily bows out.

What does all of this mean for young Inuit who are thinking of suicide? Clearly, it is not enough to focus on things that facilitate the transition from suicidal ideation to actual suicide. That approach might work in southern Canada, where suicide tends to result from transient episodes that push people up and over the threshold of suicidal ideation. Among the Inuit, the threshold seems to be lower and the focus should be more on preventing ideation, specifically by giving young Inuit a greater feeling of self-worth and social usefulness.

References

Brent, D.A. & J.J. Mann. (2005). Family genetic studies, suicide, and suicidal behavior, American Journal of Medical Genetics Part C: Seminars in Medical Genetics, 133C, 13-24.

Buss, D.M. (1999). Evolutionary Psychology. The New Science of the Mind, Boston: Allyn and Bacon.

de Catanzaro, D. (1991). Evolutionary limits to self-preservation, Ethology and Sociobiology, 12, 13-28.

de Catanzaro, D. (1995). Reproductive status, family interactions, and suicidal ideation: Surveys of the general public and high-risk group, Ethology and Sociobiology, 16, 385-394.

Dufour, R. (1994). Pistes de recherche sur les sens du suicide des adolescents inuit, Santé mentale au Québec, 19, 145-162.

Fu, Q., A.C. Heath, K.K. Bucholz, E.C. Nelson, A.L. Glowinski, J. Goldberg, M.J. Lyons, M.T. Tsuang, T. Jacob, M.R. True & S.A. Eisen. (2002). A twin study of genetic and environmental influences on suicidality in men, Psychological Medicine, 32, 11-24.

Kirmayer, L.J., L.J. Boothroyd, S. Hodgins (1998). Attempted Suicide among Inuit youth: Psychosocial correlates and implications for prevention, Canadian Journal of Psychiatry, 43, 816–822.

Were native Europeans replaced?

2011-12-03T10:44:00.011-05:00

Spread of farming in Europe. Cultural diffusion or population replacement? Source

Between 9,000 and 3,000 years ago farming spread through Europe and replaced hunting, fishing, and gathering. Was this process just a change in lifestyle? Or was it also a population change? Did Middle Eastern farmers replace native Europeans?

For Greg Cochran, the answer is clear:

Increasingly, it looks as if the hunter-gatherers who lived in Europe at the end of the ice age have been largely replaced. Judging from all those U5 mtdna results from ancient skeletons, I’d say that the hunters don’t account for more than 10% of the ancestry of modern Europeans. (Cochran, 2011)

Actually, the U5 haplogroup remained common after the transition to farming. This was the conclusion of a study of 92 Danish human remains that ranged in time from the Mesolithic to the Middle Ages. The study found genetic continuity from late hunter/gatherer/fishers to early farmers:

The extent to which early European farmers were immigrants or descendents of resident hunter-gatherers (replacement vs. cultural diffusion) has been widely debated, and new genetic elements have recently been added. A high frequency of Hg U lineages , especially U5, has been inferred for pre-Neolithic Europeans based on modern mtDNA data, with Hg U5 being fairly specific to Europe. [...] Our study therefore would point to the Early Iron Age and not the Neolithic Funnel Beaker Culture as suggested by Malmstrom et al. (2009), as the time period when the mtDNA haplogroup frequency pattern, which is characteristic to the presently living population of Southern Scandinavia, emerged and remained by and large unaltered by the subsequent effects of genetic drift (Melchior et al., 2010)

Thus, the sharp genetic divide was not between late hunter/fisher/gatherers and early farmers. It was between the earliest farmers and groups that had been farming for at least a millennium or so. The evidence is more consistent with natural selection than with population replacement.

But isn’t mtDNA unresponsive to natural selection? That’s what I used to think. There is growing evidence, however, that some mtDNA loci respond to natural selection. In particular, some haplogroups seem to reflect a trade-off between thermogenesis and ATP synthesis (Balloux et al, 2009). This trade-off might explain differences in disease risk between different mtDNA haplogroups. Haplogroup U, in particular, is associated with a lower risk of glaucoma (Wolf et al., 2010). There also seems to be an age-related association between this haplogroup and risk of Alzheimer’s (Santoro et al., 2010).

If true, the decline of U-type haplogroups among early farmers may reflect the different patterns of physical activity between them and hunter/fisher/gatherers.

So was it cultural diffusion or population replacement?

The jury is still out, but the consensus is moving towards a position where Middle Easterners initially established pioneer farming settlements in central Europe but were over time largely replaced by native farmers. Rowley-Conwy (2011, p. S434) describes this new model:

Our explanations must now rest on two major foundations: most Neolithic genes were native, but the major domesticates were exotic. Small-scale rather than continent-wide migrations are the best way to integrate these into one model. Agriculture in a region may have been introduced by immigrants, but that does not mean that the immigrants carried mainly Near Eastern genes (Richards 2003; Rowley-Conwy 2004b; Zvelebil 2005). The LBK, for example, originated in the Carpathian Basin; the population that moved westward emerged there carrying a complex mix of European and Near Eastern mtDNA and no doubt picking up more as it moved.

There is evidence that these pioneer farming settlements assimilated local hunter-gatherers, especially women. In at least some cemeteries, the female skeletons are likelier than the male skeletons to have come from outside the local farming community (Rowley-Conwy, 2011, p. S439). Thus, over time, this recruitment of local hunter-gatherers would have steadily diluted the original gene pool, and this dilution would have been more advanced in later, secondary settlements that budded off from the early centers of colonization.

This process was hastened by the extinction of many of the early farming settlements. In northwestern France, the Villeneuve-Saint-Germain culture represented the furthest westward extension of these colonizing farmers. After a couple of centuries, however, it disappeared and was replaced by farming cultures of local origin (Rowley-Conwy, 2011, p. S439)

References

Balloux F., L.J. Handley, T. Jombart, H. Liu, and A. Manica (2009). Climate shaped the worldwide distribution of human mitochondrial DNA sequence variation. Proceedings. Biological Sciences, 276 (1672), 3447–55.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2817182/?tool=pmcentrez

Cochran, G. (2011). First-mover advantage, West Hunter, November 25
http://westhunt.wordpress.com/2011/11/25/first-mover-advantage/#comments

Melchior, L., N. Lynnerup, H.R. Siegismund, T. Kivisild, J. Dissing. (2010). Genetic diversity among ancient Nordic populations, PLoS ONE, 5(7): e11898

Rowley-Conwy, P. (2011). Westward Ho! The Spread of Agriculturalism from Central Europe to the Atlantic, Current Anthropology, 52 (S4), S431-S451

Santoro A., V. Balbi, E. Balducci, C. Pirazzini, F. Rosini, et al. (2010). Evidence for Sub-Haplogroup H5 of Mitochondrial DNA as a Risk Factor for Late Onset Alzheimer's Disease. PLoS ONE, 5(8): e12037. doi:10.1371/journal.pone.0012037

Wolf, C., E. Gramer, B. Müller-Myhsok, F. Pasutto, B. Wissinger, & N. Weisschuh. (2010). Mitochondrial haplogroup U is associated with a reduced risk to develop exfoliation glaucoma in the German population, BMC Genetics, 11, 8

How late is too late?

2011-11-25T11:16:00.002-05:00

In pre-industrial Finland, the average woman was caught in a squeeze play. If she married too young, she and her partner might not have enough resources to start a family. If she married too old, she risked genetic extinction. None of her children might survive to adulthood and have children of their own. Source

In a previous post, I discussed how Western European societies used to postpone the age of first reproduction to the mid-20s. When this cultural pattern began is unsure, but it certainly preceded the Black Death of the 14th century and may have existed as early as the 9th century. It seems to have resulted from a combination of land scarcity and the rule of primogeniture, i.e., farms were kept intact and handed over to the eldest son when the parents died or retired. In such a situation, young couples had to wait until they had a farm of their own—and the means to start a family.

How late can a woman postpone having her first child and still be sure of perpetuating her lineage? In her mid 30s? That answer might be true today. In pre-modern societies, however, women had to start earlier. A recent study by Liu and Lummaa (2011) puts it no later than 30. Beyond 30, a woman would be faced with declines in both offspring quantity and offspring quality. Her risk of genetic extinction was proportionately higher.

In a study of rural Finnish parish records from the 18th and 19th centuries, Liu and Lummaa (2011) found that the women were 26 years old on average when they first gave birth. They had thus foregone the first decade of their reproductive life, something that would be unheard of in most traditional human societies. Yet they nonetheless managed to have 6.54 children on average.

Among these women, offspring quantity decreased with increasing age of first reproduction (AFR). This was partly because the time window for reproduction was narrower and partly because more of the reproduction was taking place during years of reduced fertility. Offspring quality held constant until the age of 30 and then too decreased.

The study defined “offspring quality” as the probability that one’s children will survive to adulthood and have children of their own. On average, 60% of the offspring survived to 15 years of age and 47% had children of their own. AFR did not affect offspring quality among mothers under 30. Over 30, higher AFR was associated with a lower probability of the children surviving to adulthood and a lower probability that the surviving children would have families of their own.
Why did fewer of these children survive to adulthood? The data provide no direct answers. One reason may be that older mothers tend to have children with lower birth weights, which in turn may lead to early death. Older mothers are also at risk of having children with birth defects.

And why did fewer of the surviving children have children of their own? Again, the data provide no direct answers. It may be that many of these children were physically or behaviorally compromised and thus less able to attract potential mates.

What does all of this mean for us today? In the short term, it means that a large part of the current population is headed towards genetic extinction. In the long term, there will be selection for increased fertility at older ages:

In today´s society however, women do not start childbearing until an older age as marriage is often delayed, and casual or short-term relationships and divorce are more common. As a result, the natural selection maintaining young-age fertility might weaken and the relative strength of natural selection on old-age fertility could increase, something that could potentially lead to improvements in old-age fertility over many generations.

Duncan Gillespie from the University of Sheffield´s Department of Animal and Plant Sciences, said: "In today´s society, family-building appears to be increasingly postponed to older ages, when relatively few women in our evolutionary past would have had the opportunity to reproduce. As a result, this could lead to future evolutionary improvements in old-age female fertility.” (Davis, 2011)

References

Davis, S. (2011). Marriage patterns drive fertility decline,
http://www.sheffield.ac.uk/mediacentre/2010/1715.html

Liu, J. and V. Lummaa. (2011). Age at first reproduction and probability of reproductive failure in women, Evolution and Human Behavior, 32, 433-443.

Vitamin D and Northern Natives

2011-11-19T15:27:00.004-05:00

Annual average exposure to erythema-inducing UV radiation at ground level. Source: Jablonski & Chaplin, 2000. At high northern latitudes, vitamin D can be obtained only from one’s diet, notably fatty fish. Yet many northern native peoples consume little fish. Have they evolved a different vitamin D metabolism?

I’ve just published an article on population differences in vitamin D metabolism, specifically about northern native peoples. Comments are welcome.

Abstract

Vitamin-D deficiency seems to be common among northern native peoples, notably Inuit and Amerindians. It has usually been attributed to: 1) higher latitudes that prevent vitamin-D synthesis most of the year; 2) darker skin that blocks solar UVB; and 3) fewer dietary sources of vitamin D. Although vitamin-D levels are clearly lower among northern natives, it is less clear that these lower levels indicate a deficiency. The above factors predate European contact, yet pre-Columbian skeletons show few signs of rickets—the most visible sign of vitamin-D deficiency. Furthermore, because northern natives have long inhabited high latitudes, natural selection should have progressively reduced their vitamin-D requirements. There is in fact evidence that the Inuit have compensated for decreased production of vitamin D through increased conversion to its most active form and through receptors that bind more effectively. Thus, when diagnosing vitamin-D deficiency in these populations, we should not use norms that were originally developed for European-descended populations who produce this vitamin more easily and have adapted accordingly.

References

Frost, P. (2011). Vitamin D deficiency among northern Native Peoples: A real or apparent problem? International Journal of Circumpolar Health, early view
http://www.ijch.fi/aheadofprint.php

Jablonski, N.G. and G. Chaplin (2000). The evolution of human skin coloration, Journal of Human Evolution, 39, 57-106.

The Western European marriage pattern

2011-11-12T11:07:00.003-05:00

The ‘Hajnal line’ marks the eastern limit of a longstanding pattern of late and non-universal marriage. The line in red is Hajnal's. The dark blue lines show areas of high nuptiality West of the Hajnal line. Source

In the 17th and 18th centuries, settlers emigrated from land-poor France to land-rich Canada. The result was a lower age of marriage. Young men and women no longer had to wait for their parents to hand over the family farm. Land was plentiful, and early family formation much easier.

This new social reality led to a new biological reality. From one generation to the next there was a steady contraction of the time between age of marriage and age of first birth. Married women—many as young as 15— were getting pregnant faster. The mean age of full reproductive maturity seems to have slowly fallen at a steady rate, apparently through the reproductive success of women who could better exploit the opportunities for early family formation (Milot et al., 2011).

But what about the homeland of these French settlers? Had that land-poor environment selected for a later onset of full reproductive maturity? That would seem to be a logical inference. Late and non-universal marriage was in fact the pattern throughout Europe west of a line stretching from Trieste to St. Petersburg:

By 1650, when village reconstitution studies become sufficiently numerous to render the generality of the pattern indubitable, the average age of women at first marriage was twenty-four or over, 7 to 20 per cent of women never married, and the incidence of childbirth out of wedlock was below 3 per cent. This marital pattern restricted fertility massively. A very considerable minority of women remained single and bore no children; those who married bore none for the first ten years of their fecund life-phase, on average. If they had their last child at the age of forty, their entire reproductive careers would span roughly fifteen years, a long time by modern standards but remarkably brief in a pre-transition context. Resulting fertility was less than half the rate that would have been achieved if all women between fifteen and fifty were married. (Seccombe, 1992, p. 184)

The ‘Western European marriage pattern’ was initially thought to have developed after the Black Death of the mid-14th century. But this belief has been challenged by a study of marriage between 1252 and 1478 in an English community:

The average age at first marriage in the Lincolnshire Fenland before the Black Death would be 24 years for the woman and 32 years for the man. The wife would die one year before her husband and the marriage would last for about 13 years. The couple could have six children, if their fertility was higher than average, of whom, judging by pedigrees, perhaps three would survive to become adults. After the Black Death the mean age would be 27 for the woman and 32 for the man. The husband would die three years before his wife and the marriage would last about 12 years. Again the couple could have six children, of whom perhaps three would survive to become adult. (Hallam, 1985, p. 66)

This pattern of late marriage may have been accentuated by the Black Death, but it was already present beforehand. Hallam (1985, p. 56) cites additional evidence for late marriage farther back in 9th-century France. On the estates of the Abbey of St Germain-des-Prés near Paris, about 16.3% of all adults were unmarried. In Villeneuve-Saint-Georges, the figure was 11.5%. Seccombe (1992, p. 94) cites a 9th-century survey of the Church of St Victor of Marseille, where both men and women appear to have married in their mid to late twenties.

Going even farther back, Seccombe (1992, p. 94) cites the Roman author Tacitus’ reference to Germanic women being “not hurried into marriage [and] as old and as full-grown as the men [who were] slow to mate.”

So when did the Western European marriage pattern begin? I suspect its origins lie in the late Neolithic of Western Europe, when farming communities had reached a saturation point. With farmland in short supply, young men and women had to wait their turn before they could marry and have children of their own. And some would never marry.

What happened to these never-married? They may have turned toward community service of one kind or another. If they couldn’t have children of their own, they would’ve invested their energies in helping others of their community—who were often their kinfolk. In this respect, the Catholic Church may have simply adopted and further developed a cultural pattern that was already present in Western Europe.

By the early Christian era, this pattern was clearly in evidence: monks and nuns dedicated their lives to creating centers of learning and, eventually, colleges and universities. They also founded hospices for the sick and injured. Much of what we now call the ‘welfare state’ has its origins in the work of these celibate men and women.

Together with the prohibition of cousin marriage, this pattern of lengthy and sometimes lifelong celibacy paved the way for a future of larger and more open societies where the State, and not one’s clan, would provide collective services. Of course, it wasn’t planned that way. Nothing is planned in cultural or biological evolution. Western Europe simply accumulated a mix of cultural traits that would later make possible the rise of ‘modern society.’

Did this marriage pattern shape the biology of Western Europeans through natural selection? Was there gene-culture co-evolution? This is likely with respect to the pace of sexual maturation. Keep in mind that the time between menarche and first birth was ten to twelve years on average. Nature abhors a vacuum, and there would have been a tendency to slow the pace of sexual maturation for both biological and psychological traits. Just as land-rich North America selected for successful pregnancy at younger ages, the reverse had probably happened in land-poor Europe.

References

Hallam, H.E. (1985). Age at first marriage and age at death in the Lincolnshire Fenland, 1252-1478, Population Studies, 39, 55-69.

Milot, E., F.M. Mayer, D.H. Nussey, M. Boisvert, F. Pelletier, and D. Réale. (2011). Evidence for evolution in response to natural selection in a contemporary human population, Proceedings of the National Academy of Sciences (USA), early view

Seccombe, W. (1992). A Millennium of Family Change. Feudalism to Capitalism in Northwestern Europe, London: Verso.

Apples, oranges, and genes

2011-11-05T15:13:00.003-05:00

Publicly funded misinformation. Source: PBS website

In human genetics, a ‘population’ is a group of individuals who share ancestry and hence genes. This sharing is not absolute. There is always some gene flow from outside, and sometimes “outside” means another species. We humans, for example, have received genes not only from Neanderthals and Denisovans but also from … viruses.

In addition, new gene variants are constantly arising through mutation. Most of them are harmful or useless. But some are useful and will thus spread through the population.

So below the species level, and often even at the species level, population boundaries tend to be fuzzy. Genes vary both between and within populations.

You’ve undoubtedly heard that there is much more genetic variation within human populations than between them, this being true even for the large continental populations we used to call ‘races.’ This was the finding of the geneticist Richard Lewontin (1972), and others have concluded likewise. You’ve probably not heard, however, that the same kind of genetic overlap exists between many sibling species that are nonetheless distinct in anatomy and behavior (Frost, 2011).

How come? First, keep in mind that genes vary a lot in adaptive value. Some are little more than ‘junk DNA.’ Others code for structural proteins that form the building blocks of flesh and blood. Others still are very important because they code for regulatory proteins that control how other genes behave and, hence, the way an organism grows and develops. The last kind of gene accounts for only a tiny fraction of the genome. Most genes have modest effects, or none at all.

Second, keep in mind that different populations occupy different environments and are thus exposed to differences in natural selection. In most species, these differences are due to physical environments that differ in climate, vegetation, and wildlife. Humans also have to adapt to cultural environments that differ in social structure, belief systems, and technology. In either case, when a gene varies between two populations the cause is probably a difference in natural selection, since the population boundary also separates different selection pressures. Conversely, when a gene varies within a population this variation is less likely to have adaptive significance. It hasn’t been flattened out by the steamroller of similar selection pressures.

This is one aspect of “Lewontin’s fallacy.” Within-population variation isn’t comparable to between-population variation. It’s like comparing apples and oranges.

Another aspect of Lewontin’s fallacy is that natural selection within a population exercises a leveling effect only on phenotypes, and not on genotypes. If two gene variants have a similar phenotypic effect, natural selection will take longer to replace one with the other. Sometimes, this sort of diversity will persist indefinitely because epidemics often spare individuals whose surface proteins are somewhat different from those of their neighbors.

Thus, within-population variation tends to consist of different gene variants at different loci whose effects nonetheless point in the same general direction. To some degree, these variants can stand in for each other. If one is absent, another one might do the trick. This is probably why population differences are more sharply defined if several gene loci are compared simultaneously. If we chart how each gene varies geographically and then superimpose these maps on top of each other, the resulting composite map will show population differences in sharper relief (Edwards, 2003; Mitton, 1977; Mitton, 1978; Sesardic, 2010).

This point has been made by Emmanuel Milot, the principal author of the paper I reviewed in my last post. His research team found that the time between marriage and first birth steadily shrank among succeeding generations of French Canadians on Île aux Coudres (Milot et al., 2011). In the land-rich environment of the New World, there was strong selection for married women to get pregnant faster. A genetic difference has thus developed between French Canadians and the French who remained in France.

But this difference is not due to a few genes. As Milot points out, natural selection tends to produce effects at many different genes:

“We should not think that there are genes that code specifically for age at first reproduction. In fact, this type of trait is probably influenced by hundreds, even thousands, of genes. These genes act on other characteristics, like body weight at birth, age at first menstruation, or even personality traits, which impact on age at first birth” (Bourdon, 2011)

This point is important. If two populations differ at one gene, and if the difference is sensitive to natural selection, they probably also differ at many other genes. The same selection pressure that caused one difference has almost certainly caused others. Typically, we see only the tip of the iceberg—a gene variant that produces an obvious effect in affected individuals, such as illness. Most gene variants, however, don’t cause medically recognized illnesses, and their effects also tend to be subtler.

References

Bourdon, M-C. (2011). L’espèce humaine. Toujours en évolution. UQAM. Entrevues
http://www.uqam.ca/entrevues/entrevue.php?id=965

Edwards, A.W.F. (2003). Human genetic diversity: Lewontin’s fallacy. BioEssays, 25, 798-801.

Frost, P. (2011). Human nature or human natures? Futures, 43, 740-748. http://dx.doi.org/10.1016/j.futures.2011.05.017

Lewontin, R.C. (1972). The apportionment of human diversity. Evolutionary Biology, 6, 381-398.

Milot, E., F.M. Mayer, D.H. Nussey, M. Boisvert, F. Pelletier, and D. Réale. (2011). Evidence for evolution in response to natural selection in a contemporary human population, Proceedings of the National Academy of Sciences (USA), early view

Mitton, J.B. (1977). Genetic differentiation of races of man as judged by single-locus and multilocus analyses, American Naturalist, 111, 203-212.

Mitton, J.B. (1978). Measurement of differentiation: reply to Lewontin, Powell, and Taylor, American Naturalist, 112, 1142-1144.

Sesardic, N. (2010). Race: a social destruction of a biological concept, Biology and Philosophy, 25(2), 143-162.

Bringing reproductive maturity into line with the age of marriage

2011-10-29T12:55:00.002-05:00

Île aux Coudres, a French Canadian community on an island in the St. Lawrence

Human biodiversity is slowly making headway in academia. It has three defining principles:

1. Evolution did not end, or even slow down, with the advent of Homo sapiens. It has actually accelerated.

2. It especially accelerated about 10,000 years ago, when the rate of genetic change rose over a hundred-fold among early modern humans. This acceleration didn’t happen because they were spreading into new physical environments with different climates, topographies, vegetation, and wildlife. By then, humans had already spread throughout the world from the equator to the arctic. They were now spreading into new cultural environments with different technologies, social structures, belief systems, and means of subsistence.

3. The human species has therefore experienced more genetic change over the past 10,000 years than over the previous million years. This change has particularly involved genes for mental, behavioral, and life-history traits (Frost, 2011; Hawks et al., 2007).

One life-history trait is the age of first reproduction (AFR). Because AFR is highly heritable, there may have been co-evolution between biology and culture. In other words, natural selection has tended to bring full reproductive maturity into line with the age when young couples have enough resources to marry and start a family.

When Europeans first began to settle North America, they came from a land-poor environment where young people had to postpone marriage and family formation. Typically, they had to wait until their parents handed over the farm in whole or in part. This tendency toward late marriage was widespread throughout Western Europe, so much so that it has been dubbed the ‘Western European Marriage Pattern’:

[…] the late and non-universal marriage pattern was definitely prevalent across Northwestern Europe in the seventeenth century. By 1650, when village reconstitution studies become sufficiently numerous to render the generality of the pattern indubitable, the average age of women at first marriage was twenty-four or over, 7 to 20 per cent of women never married, and the incidence of childbirth out of wedlock was below 3 per cent. This marital pattern restricted fertility massively. A very considerable minority of women remained single and bore no children; those who married bore none for the first ten years of their fecund life-phase, on average. If they had their last child at the age of forty, their entire reproductive careers would span roughly fifteen years, a long time by modern standards but remarkably brief in a pre-transition context. Resulting fertility was less than half the rate that would have been achieved if all women between fifteen and fifty were married. (Seccombe, 1992, p. 184)

All of this changed when Europeans began to settle in the “New World.” Suddenly, land was no longer a constraint on marriage, and early marriage became the norm. With the downward shift in the age of marriage, was there a corresponding downward shift, via natural selection, in the age of full reproductive maturity?

Yes, according to a recent study of Île aux Coudres, a French Canadian community on an island in the St. Lawrence. Over a period of 140 years, from 1800 to 1940, this community saw its mean AFR fall by four years. This decline was driven not by a lowering of the mean age of marriage (which now remained stable) but by a shortening of the mean interval between marriage and first birth.

The decline in AFR seems to have been real, and not an artefact of incomplete marriage and birth records. In fact, the church registers provide exceptionally detailed birth and marriage data. Nor was it an artefact of an influx of people with lower AFRs. Almost everyone on Île aux Coudres is descended from thirty families who settled the island between 1720 and 1773.

Could the reason have been changes to diet and nutrition? Unlikely.

The advancement of age at maturity, as well as increases in fertility, may reflect plastic responses to improvements in nutritional conditions, such as those observed during the 19th and 20th centuries in Western societies. Better-fed women grow faster, mature earlier and in a better physiological state, and are more fecund. Importantly, alongside such plastic responses in reproductive traits, we would expect an increase in infant and juvenile survival rates with time. Despite some fluctuations, infant and juvenile survival rates on île aux Coudres were not higher at the end of the study period than at the beginning. (Milot et al., 2011)

When I first heard of this study, I thought that some kind of cultural lag might have been responsible. Old habits die hard. Perhaps many of the early settlers, with memories of the old country, were still afraid of not having enough land to support a family, even after they had decided to marry. This reticence would have then gradually disappeared as memories of the old country disappeared.

Such a change in mentality, however, would have happened much more among the earlier generations than among the later ones. Yet this is not what we see in the data. AFR changed at the same rate from one generation to the next throughout the 140-year period. Couples married after 1870 showed the same rate of change as couples married before 1870. Indeed, this steady rate of change seems to rule out most socio-cultural explanations, particularly those that involve some kind of re-adjustment to new conditions. In any case, the study period (1800 to 1940) postdates the years of immigration and settlement (1720 to 1773).

We’re certainly going to see more studies like this one, either from Île aux Coudres or from other regions of French Canada. In general, French Canadian communities are ideal for the study of human microevolution. Records of births, marriages, and deaths are remarkably complete over a span of three centuries, and the inhabitants tended to stay put in the same locality generation after generation. For several regions of Quebec, we already have complete genealogical databases that could be enriched with genetic data for the most recent generations.

Reference

Frost, P. (2011). Human nature or human natures? Futures, 43, 740-748. http://dx.doi.org/10.1016/j.futures.2011.05.017

Hawks, J., E.T. Wang, G.M. Cochran, H.C. Harpending, & R.K. Moyzis. (2007). Recent acceleration of human adaptive evolution, Proceedings of the National Academy of Sciences (USA), 104, 20753-20758.

Milot, E., F.M. Mayer, D.H. Nussey, M. Boisvert, F. Pelletier, and D. Réale. (2011). Evidence for evolution in response to natural selection in a contemporary human population, Proceedings of the National Academy of Sciences (USA), early view

Seccombe, W. (1992). A Millennium of Family Change. Feudalism to Capitalism in Northwestern Europe, London: Verso.

End of an era

2011-10-22T14:15:00.003-05:00

In 2003, Qaddafi dismantled Libya’s nuclear arms program in exchange for better relations with the West. At the time, it seemed like a great idea ...

Let me summarize my last series of posts.

We are nearing the end of relative global peace, specifically the peace that has reigned since the Korean armistice was signed back in 1953. This era is ending because of changes to the international system over the past two decades and to the nature of global peace itself.

First, a balance of terror no longer exists to contain regional conflicts and thus keep them from going global. Military alliances have become less specific in their aims and reciprocal responsibilities. In the East, this has happened through the replacement of the Warsaw Pact by the Shanghai Cooperation Organisation (SCO). In the West, this has happened through a broadening of NATO to include new members and new aims, as well as through a general weakening of commitment among older members.

Second, global peace no longer maintains an acceptable status quo. Previously, states merely pushed the envelope of peace here and there to see what they could get away with. There was also terrorist action by dispossessed groups that had nothing to gain from the status quo. But such groups, by definition, were geopolitically marginal. Peace was acceptable to those who had the power to destroy it.

This view has radically changed in the case of North Korea. Previously, Pyongyang saw the conquest of South Korea as an almost hypothetical goal that could be pushed indefinitely into the future. The status quo was wrong but bearable. Today, it’s no longer bearable. The other Korea has created a new dynamic by embracing post-nationalism, multiculturalism, and large-scale immigration.

This might not matter if the North had followed the same ideological evolution as the South. But it hasn’t. The North has been frozen in time. It still sees itself as a vehicle for preserving and perpetuating the Korean people. It still adheres to values that were normal throughout the world only a half-century ago. Thus, North Korea can no longer accept the “status quo” even as a temporary expediency. It now sees an invasion of the South as something that must happen soon—before the demographic changes become irreversible.

Elsewhere, the status quo has likewise taken on a new dynamic. With the end of the Cold War, it increasingly means American military interventions that would have been unthinkable previously. There is now an “imbalance of terror”—the United States is free to overthrow one unfriendly regime after another without triggering a major war. This trend has not gone unnoticed, particularly by the North Koreans:

North Korea’s official news agency carried comments this week from a Foreign Ministry official criticizing the air assault on Libyan government forces and suggesting that Libya had been duped in 2003 when it abandoned its nuclear program in exchange for promises of aid and improved relations with the West.

Calling the West’s bargain with Libya “an invasion tactic to disarm the country,” the official said it amounted to a bait and switch approach. “The Libyan crisis is teaching the international community a grave lesson,” the official was quoted as saying Tuesday, proclaiming that North Korea’s “songun” ideology of a powerful military was “proper in a thousand ways” and the only guarantor of peace on the Korean Peninsula. (McDonald, 2011)

There has indeed been an arms buildup in countries that fear eventual U.S. intervention, particularly China, Russia, and Iran. None of them wish to go one-on-one with the U.S., for obvious reasons. The result has been the formation of a new pan-Eurasian alliance: the Shanghai Cooperation Organisation (SCO). Politics makes strange bedfellows, and it is indeed strange to see the Islamic Republic of Iran wanting to bed down with China and Russia, both of which have restive Muslim minorities.

Despite the arms buildup, and an ever more fragile international system, global peace might still continue indefinitely. The destabilizing factor is really the spread of an increasingly aggressive globalist ideology and, correspondingly, resistance by various forms of anti-globalism.

For comparison, we can turn to the gradual breakdown of the post-Napoleonic peace that lasted from 1815 to 1914. That century-long peace was made possible by the Concert of Europe, a coalition of conservative regimes that worked together to keep the continent free of liberalism and nationalism. The coalition fell apart during the second half of the 19th century and gave way to a looser system of opposing military alliances.

The really destabilizing factor, however, was the return of liberalism and nationalism to the continent. Demands grew for democratic constitutions and for the creation of states along ethnic lines. Eventually, much if not most of Europe’s intelligentsia came to see the status quo as an archaic monstrosity. When global war finally broke out in 1914, it was readily framed as a struggle between “freedom” and “tyranny.”

From the “old order” to nationalism to globalism

Today, the rise of globalism might seem to promise a return to that lost era, when liberalism and nationalism were still on the margins of political life. That old order, however, allowed people to organize their lives along traditional lines—on the basis of kinship and ethnicity. Nor was there any effort to “elect a new people.” Loyalty ran both ways, and the ruling aristocracies felt bound to their subjects in a way that would seem incomprehensible to our current elites.

Indeed, the late 19th century saw liberalism and nationalism begin a process that would eventually culminate in today’s globalism. Both liberals and nationalists wanted to open up the tight little world of small communities. Both wished to create a larger community, the nation state, that would provide more room for individual freedom and individual identity. Both viewed “parochialism” as an obstacle to progress and the creation of a more rational social order. Above all, both saw the leveling of local identities as the means to create a society that would be militarily stronger and economically more viable.

Nationalism has thus paved the way for globalism. It has merged local identities into national identities that are, to varying degrees, synthetic and lacking in authenticity. The more artificial the resulting national identity, the easier it has been for globalism to present itself as the next logical step.

From globalism to what?

There is one more way in which globalism resembles nationalism, as well as other ideologies. It tends to push ahead while ignoring evidence that things aren’t working out as planned. And this blindness will likewise condemn it to the same fate that has befallen other ideologies. Until then, however, it will likely do much harm.

Will globalism collapse through an eventual global conflict, like fascism in the mid-20th century? Or will it collapse under the weight of its own contradictions, like communism a half-century later? And just what will post-globalism look like? These are questions for which I have no ready answers. Perhaps you do.

References

McDonald, M. (2011). North Korea suggests Libya should have kept nuclear program, New York Times, March 24, 2011.
http://www.nytimes.com/2011/03/25/world/asia/25korea.html

Towards an imbalance of terror?

2011-10-15T13:56:00.005-05:00

Member and observer states of the Shanghai Cooperation Organisation (SCO). In both the east and the west, defense alliances have become less centralized and more loosely defined since the end of the Cold War. They no longer contain regional conflicts and may actually cause them to go global. (source)

Tensions are mounting on the Korean Peninsula, as seen last November in the bombardment of Yeongpyeong Island. Is a second Korean War imminent?

Not likely, if the general reaction is to be believed. An example of this thinking is given by David Kang, director of the Korean Studies Institute at USC:

We often call the situation a “powderkeg” or a “tinderbox,” implying a very unstable situation in which one small spark could lead to a huge explosion. But the evidence actually leads to the opposite conclusion: we have gone 60 years without a major war, despite numerous “sparks” such as the skirmish that occurred last week. If one believes the situation is a tinderbox, the only explanation for six decades without a major war is that we have been extraordinarily lucky. I prefer the opposite explanation: deterrence is quite stable, both sides know the costs of a major war, and both sides—rhetoric aside—keep smaller incidents in their proper perspective. (Kang, 2010)

Yet the current situation differs from the one that prevailed during most of those sixty years. From 1953 to the late 1980s, there was no second Korean War because neither the United States nor the Soviet Union wanted one. Both parties considered the division of the Korean Peninsula to be an acceptable compromise. The only people really unhappy were the Koreans themselves, who on their own could do little. The decision to go to war ultimately lay in Washington and Moscow.

This situation has changed since the Cold War ended in the late 1980s. Moscow has ceased to be a decision center for global conflict, and the Warsaw Pact has given way to a much more decentralized defense pact: the Shanghai Cooperation Organisation (SCO). NATO still exists and has even accepted new member states, but it too is now a looser organization with less clearly defined obligations. Many members have refused to support the latest military operations in Afghanistan and Libya.

The end of the Cold War also stopped the Soviet Union’s direct and indirect subsidies of North Korea. Throughout the 1990s, the regime in Pyongyang teetered on the brink of collapse, with reunification being the most likely outcome. At the time, many South Koreans actually feared this prospect, having seen the high cost of reunification in Germany.

That window of opportunity closed in the early 2000s. By then, Pyongyang had weathered the worst of the storm, as had its semi-allies China and Russia. By then too, the South had embraced its new Global Korea policy—an explicit shift to post-nationalism, multiculturalism, and large-scale immigration. In 2006, Pyongyang’s leading newspaper, Rodong Sinmun, angrily denounced the new policy as “an unpardonable argument to obliterate the race by denying the homogeneity of the Korean race and to make an immigrant society out of South Korea, to make it a hodgepodge, to Americanize it” (Koehler, 2006).

The Global Korea policy has fundamentally changed Pyongyang’s vision of the future. Conquest of South Korea is no longer a goal to be pushed indefinitely into the future. It is something that must happen soon—before the demographic changes in the South become irreversible.

So the North Koreans are upset. But what can they do? Any invasion of the South would trigger an American intervention. And it is doubtful whether China would come in on Pyongyang’s side. As David Kang points out:

If it is an unprovoked North Korean invasion, then the North probably goes it alone. Even China is unlikely to support such a war. Although the Chinese are supportive of North Korea, they are clearly not in favor of starting a war on the peninsula that would have enormous negative consequences for every country in the region. (Kang, 2010)

In a conflict between North Korea alone and the United States, there is little doubt about the eventual outcome. The United States would win.

[…] although North Korea possesses a significant missile arsenal, Pyongyang is unlikely to contemplate launching full scale strikes against anyone, given the conservative nature of the regime which fears for its own survival, and the inevitable scale of US retaliation which would almost certainly result in the destruction of North Korea. The same reality applies to North Korea’s million plus army, which despite being among the largest in the world, is devoid of any real sustainable offensive capacity. Even in the unlikely scenario that the regime considers launching an invasion of South Korea, North Korea simply lacks the most basic resources that would be needed to mount an aggressive military campaign. Conversely, the South Koreans and the US have the personnel and technology, especially air supremacy, to quickly neutralise any North Korean offensive strike (Fazio, 2011)

Clearly, the above scenario holds little appeal for the North Koreans. But there are other scenarios. The most attractive one, from their standpoint, would bring other nations into the war on North Korea’s side, especially China.

Yet, as David Kang noted, China is at most a semi-ally. With some reluctance, it might even accept reunification of the peninsula under South Korean control, the only proviso being the departure of U.S. troops. In the mid-1990s, this outcome seemed very likely to the Chinese:

[There] would come other important developments, most important the eventual collapse of North Korea and the reunification of the Korean Peninsula. It is awkward for the Chinese to acknowledge this publicly given their long relationship to the ultraorthodox Communist regime in North Korea, but Beijing has to realize that that regime, which has literally bankrupted the country it rules, is doomed and that reunification under South Korea is likely in the next decade or two. Foreign-affairs experts in China told us that they doubted American troops would remain in Korea long after reunification began, a prediction that seems realistic, since the reason for the troops, the North Korean threat, would have disappeared. (Bernstein & Munro, 1998, p. 176)

Today, such an outcome seems unlikely. Germany has been reunified for two decades, and U.S. troops are still there. For a number of geopolitical reasons, the Americans wish to keep a military presence in mainland East Asia just as they wish the same in continental Europe. Even if U.S. troops did leave, South Korea’s political class would remain oriented to the United States and would tilt a reunified Korea in that direction. China would thus have a U.S. ally right next to its industrial heartland of Manchuria.

For these reasons and others, China will not abandon Pyongyang:

Despite Chinese rhetoric in support of peaceful unification of the Koreas, Beijing fears that a unified Korea would have strong ties with the United States, eliminating the buffer zone that North Korea provided. A reunified Korea would also eliminate North Korea’s value as political and military leverage against the U.S. stance on Taiwan. Lastly, China has a population of nearly two million ethnic Korean-Chinese living just north of the Chinese-North Korean border. A unified Korea might provide the impetus for a separatist movement. Therefore, instead of a reunified Korea, China’s long-term objective is to encourage an evolution of the DPRK into a stable and economically prosperous, non-nuclear regime that remains aligned toward Beijing. (Mrosek, 2011, p. 4)

As a semi-ally, how might China enter a second Korean conflict on Pyongyang’s side? There seem to be four conditions:

1. North Korea is not perceived as the aggressor. If the U.S. intervenes in North Korea as it has previously in Kosovo, Iraq, and Libya, the Chinese would at least covertly assist Pyongyang.

2. Tensions are already high between China and the U.S. This could come about for a number of reasons: Taiwan; the trade balance; concerns over Tibet and the South China Sea; etc.

3. Other SCO member states are willing to provide at least covert assistance.

4. NATO is increasingly divided, with some member states being members in name only.

The above scenario is certainly far from science fiction. The United States could intervene in North Korea if it believed that the regime was about to collapse and that a popular uprising was in progress. After all, the same kind of intervention seemed to work in Libya. There is also the mistaken belief, common among U.S. policymakers, that the Chinese would support the U.S. or at least do nothing (Mrosek, 2011, pp. 50-52). Ironically, that belief can be traced in part to the above passage by Bernstein and Munro.

Just as mistakenly, the Americans, and perhaps also the Chinese, believe that the resulting conflict could be contained to the Korean Peninsula—much like the first Korean War. Yet such containment is less likely today than it was in 1950-1953. Back then, both the United States and the Soviet Union were war-weary and wished to consolidate their newly won spheres of influence. There was thus a deliberate effort to keep the war from spreading, as seen in Truman’s sacking of Gen. MacArthur. Finally, although many nations fought in the Korean War, only two of them—the United States and the Soviet Union—had the power to decide whether it would remain regional or go global.

The same principle held throughout the Cold War. The international system was essentially a duopoly—a “balance of terror.” When the Hungarian Revolution broke out, the United States thought long and hard … and did nothing. When the two power blocs did intervene in regional conflicts, as in Korea and Vietnam, the conflicts remained regional.

With the end of the Cold War, the United States has been more willing to engage in military interventions that would have been unthinkable before. One result has been an arms buildup in countries that fear U.S. intervention, notably China, Russia, and Iran. This fear was instrumental to creation of the SCO. Unlike the Warsaw Pact, however, the SCO has no single decision center, and its member states do not have clearly defined obligations to each other.

The same could be said for NATO. Its aims are no longer clearly defined and its members more and more reluctant to engage in theatres of war that now lie well outside Europe. Increasingly, NATO is providing a cover for operations led primarily by the United States and any other member states that wish to tag along.

This new international system can do little to contain regional wars. It may indeed have the potential to draw one nation after another into an initially minor conflict, especially if they see it as a prelude to similar interventions to be launched against themselves. The world situation today thus scarcely resembles 1950. It seems to have more in common with … 1914.

References

Bernstein, R. & R.H. Munro. (1998).The Coming Conflict with China, New York: Vintage Books.

Fazio, D. (2011). The North Korean security threat: an historical context and current policy options, ERAS, 12(2), 1-25.

Kang, D. (2010). Korea Expert Answers Your Questions.

http://iamkoream.com/nk-questions/

Koehler, R. (2006). I guess this means the DPRK won’t be inviting Hines Ward for a visit (English translation of Rodong Sinmun editorial).
http://www.rjkoehler.com/2006/04/27/i-guess-this-means-the-dprk-wont-be-inviting-hines-ward-for-a-visit/

Mrosek, D.M. (2011). China and North Korea: A Peculiar Relationship, thesis, Naval Postgraduate School, Monterey, California.
http://edocs.nps.edu/npspubs/scholarly/theses/2011/March/11Mar_Mrosek.pdf

They won't be the only ones

2011-10-08T09:17:00.004-05:00

North Korean shelling of Yeongpyeong Island, November 23, 2010. Why are tensions rising in Korea?

There has been much talk about B.R. Myers’ book: The Cleanest Race: How North Koreans See Themselves—and Why It Matters. Far from being communists, the North Koreans are, well, Nazis. And that matters a lot to us. Or so the book argues.

Actually, North Koreans see themselves pretty much the same way they saw themselves back in the 1950s. The most interesting change has been among Westerners—and Americans in particular. We no longer view ourselves as heirs of a specific ethnic and national tradition. Indeed, blood relationships scarcely matter at all in the West, except within the confines of the nuclear family—and even that last bastion has fallen for almost half of all adults. The market economy is becoming the sole organizing principle of our social life.

But perhaps it doesn’t really matter who has changed. What does matter is the fundamental difference in self-perception that has developed between them and us. And in recent years the difference seems to have been growing further. Concurrently, tensions have been rising on the Korean Peninsula. In 2009, a naval battle took place near the island of Daecheong. In March 2010, a North Korean submarine may have sunk the South Korean corvette Cheonan. On November 23, 2010, the North Koreans bombarded Yeongpyeong Island.

Are the two trends related? Yes, according to B.R. Myers, who concludes:

There is no easy solution to the North Korea problem, but to begin to solve it, we must realize that its behavior is aggressive, not provocative, and that its aggression is ideologically built in. Pyongyang is thus virtually predestined to push Seoul and Washington too far, thereby bringing about its own ruin. (Myers, 2010b)

It’s neither novel nor controversial to say that the Korean conflict is ideologically driven. What is new is the apparent ideological renewal of this conflict. After a lull of two decades—the “End of History”—we seem to be entering a new Cold War: post-nationalism versus nationalism, globalism versus localism, us versus them.

And the situation will probably get worse before it gets better.

Will South Korea abandon its Global Korea policy? Unlikely. This policy is backed by the local and international business community and by a broad cross-section of South Korean society. Opposition to it is disorganized, and it’s hard to see how opposition can organize within the current framework of “right” and “wrong.” Globalism is “right.” Ethnic nationalism is “wrong.” South Koreans can disagree over the ways and means of building a post-national society, but the actual goal is beyond criticism.

Needless to say, this push for post-nationalism is under way throughout the Western world. Is it going to stop? Unlikely, at least not in the near future. Will American policymakers try to call a halt in South Korea for purely pragmatic reasons, i.e., for the sake of world peace? Also unlikely. Given the reception of Myers’ book, they’ll see a golden opportunity to frame the Korean conflict in progressive terms—as a struggle to defend a modern, inclusive, and post-national society.

Will the North Koreans join us in embracing post-nationalism? Unlikely. They aren’t plugged into our current notions of right and wrong. They don’t watch American TV. Their students don’t go to American universities. They don’t have our pundits, experts, and policy wonks. They just aren’t exposed to our norms of correct thinking.

Will the North Korean regime fall? Unlikely. There’s no reason to believe it’s closer to collapse today than it was in the 1990s. Back then, the entire eastern bloc seemed to be disintegrating, and North Korea had to cope with a sudden loss of subsidies from the Soviet Union. As bad as things now are in North Korea, the situation is nowhere near as bad as it was back then. Just as importantly, its allies to the north—China and Russia—have likewise weathered the storm and are entering a period of renewed self-confidence.

All of this leads to two conclusions. First, the divide between them and us will continue to grow. There is no desire on either side for genuine rapprochement.

And the second conclusion? The North Korean leadership no longer sees the conquest of South Korea as a goal that can be pushed indefinitely into the future. It is something that must happen soon—before the demographic changes in the South become irreversible. Yes, war is coming. Soon.

In this, I claim no access to inside information. I simply know that the North Koreans care about their country and their people in a way that most of us no longer understand. To me, the eventual outcome seems inevitable.

By a strange quirk of fate the Korean Peninsula is once more becoming a fracture zone between two ways of viewing the world. And the Korean people will be the first victims.

But they won’t be the only ones.

References

Myers, B.R. (2010a). The Cleanest Race: How North Koreans See Themselves—and Why It Matters, Brooklyn: Melville House.

Myers, B.R. (2010b). North Korea will never play nice, The New York Times – The Opinion Pages, November 24, 2010
http://www.nytimes.com/2010/11/25/opinion/25myers.html

And the North Koreans?

2011-10-01T17:31:00.009-05:00

Rodong Sinmun building, Pyongyang. Source

In my last post, I discussed how South Korea has “gone global.” Its business community has emancipated itself from the nation state and is now outsourcing employment to lower-wage countries and “insourcing” lower-wage labor. The eventual result? A downward leveling of incomes. And a profound ethnic and cultural transformation. South Korea is abolishing itself.

This self-abolition is of concern not just to South Koreans. There is the little matter of their neighbors, the North Koreans. What do they think?

A naïve observer might expect a positive reaction. Doesn’t the North support international socialism? And doesn’t that mean support for multiculturalism? At most, one might expect some sadness that the political Right is piloting this transformation of South Korea.

The North Koreans actually feel differently. In April 2006, the official newspaper of the Workers’ Party, Rodong Sinmun, ran this editorial:

Recently, in South Korea, a strange game pursuing the weakening of the fundamental character of our race and making society 'multiethnic and multiracial' is unfolding.

Those responsible for this commotion are spreading confounding rumors like South Korea is a “multiracial area” mixed with the blood of Americans and several other races, how we must “overcome closed ethnic nationalism,” and we must embrace “the inclusiveness and openness of a multiethnic nation” like the United States.

The words themselves take a knife to the feeling of our people, but even more serious is that this anti-national theory of “multiethnic, multiracial society” has already gone beyond the stage of discussion. Already, they’ve decided that from 2009, content related to “multiracial, multiethnic culture” would be included in elementary, middle and high school textbooks that have until now stressed that Koreans are the “descendents of Dangun,” “of one blood line” and “one race,” and to change the terms “families of international marriage” and “families of foreign laborers” to “multicultural families.”

This is an outrage that makes it impossible to repress the rage of the people/race. To start from the conclusion, the argument for “multiethnic, multiracial society” cried for by pro-American flunkeyists in South Korea is an unpardonable argument to obliterate the race by denying the homogeneity of the Korean race and to make an immigrant society out of South Korea, to make it a hodgepodge, to Americanize it. (Koehler, 2006)

For some, the above editorial is proof that the North Koreans are nuts. They’ve gone Nazi, and there’s no longer any point in dealing with them. This is the message of a recent book that brands the North Koreans as being “ideologically closer to America’s adversaries in World War II than to communist China and Eastern Europe” (Myers, 2010, pp. 15-16).

The truth is a bit more complex. First, they’re not the ones who’ve changed. We have. We’re observing North Korea from a frame of reference that has shifted over time. Today, across our entire political spectrum, we view all forms of ethnic nationalism as outdated, if not evil. Sixty years ago, the same view was confined to the far left. It was even marginal within the leftist ideology that gave birth to North Korea.

What makes North Korea tick? Some background

Socialism, Marxism-Leninism, communism …. These are different words for the ruling ideology of the Soviet Union, particularly during Josef Stalin’s long term of office from the mid-1920s to the mid-1950s. During the 1930s, and more so during the war years, Stalin partially rehabilitated nationalism, seeing national identity as normal, legitimate, and even progressive—especially if used to mobilize opposition to fascism and international capitalism. He also promoted autarky and the belief that socialism should be made to work in one country at a time.

Meanwhile, many Koreans were looking to Soviet communism as a way to take back their country. They were really nationalists who resented the way their nation was being made to serve Japanese imperial rule and a tiny landowning class. They also understood that many nations elsewhere faced similar situations. By lending their voices to the chorus of international solidarity, they believed they were encouraging others to become masters in their own house. They were also ensuring their personal survival, since many had to flee to the Soviet Union and China.

In 1945, with the defeat of Japan and the end of the Second World War, these émigrés were brought back to form an administration in northern Korea under the auspices of the Soviet Union. From the outset, their ideology was clearly a mix of communism and nationalism:

Thus Marxism-Leninism cannot affect the deep structures of thought and behavior in any society except over a very long period: it will be grafted onto existing, longstanding roots and, while seeking to transform the roots, will itself be transformed as peoples and cultures render it intelligible to their lives. Part of the roots will be whittled away, but the branches will be pruned as well.

This has proved truer in Korea than in many settings for building socialism, precisely because of the very alienness of the setting to this fundamentally Western set of ideas. Korea had a minuscule proletariat, the beginnings of capitalism, and far too much internationalism (capitalist-style) by 1945. It therefore took from Marxism-Leninism what it wanted and rejected much of the rest: a state with potent organization, capable of providing the political basis for independence at a future point; an economic program of rapid industrialization and a philosophy of subjecting nature to human will; Lenin's notion of national liberation; Stalin's autarky of socialism-in-one country (to become in Korea socialism in one-half-a-country, and now, as Kenneth Jowitt remarked, socialism-in-one-family). Autarky fit Korea's Hermit Kingdom past, and answered the need for closure from the world economy after decades of opening under Japanese auspices. What was unusable was dispatched as soon as possible: above all the socialist internationalism including a transnational division of labor that the Soviets wanted and that Korea successfully resisted, beginning in the late 1950s.
(Cumings, 1982-1983)

In the 1950s, North Korea was more nationalistic than the rest of the communist bloc, but this difference should not be exaggerated. When communist Bulgaria pressured much of its Turkish minority to leave, the reason was that the Turks, as Turks, were incompatible with the Bulgarian nation state. When Mao offered to send Chinese migrants to Siberia, Khrushchev curtly refused: such migration would have endangered the region’s ethnic balance. There was no other reason.

The West was no less committed to the nation state. When the two power blocs went to war over the Korean peninsula, the West never condemned the North Koreans for ethnic nationalism—or the outdated idea that blood relationships are a key organizing principle of society. That idea was not yet outdated. In fact, our side accused the North Koreans of trying to subvert blood relationships—by undermining the authority of the family and by banning ancestor worship.

Since then, the North Koreans have hardly changed. But we’ve changed a lot. Today, in rejecting the nation state, we differ profoundly not just from the North Koreans but also from what we were back in the 1950s. We are strangers to everyone from that time, including ourselves.

Is this surprising? Change moves slowly in communist societies because the State keeps a tight rein on mainstream culture. There is only one authorized ideology, and it’s not easily tampered with—despite all of its revolutionary rhetoric. Any adjustments must be approved by the different organs of the ruling party, which are in the hands of individuals who have slowly risen through the party’s ranks.

The West, despite its superficial conservatism, offers much more leeway for sweeping change. The mainstream culture is an open system. It is much more vulnerable to being altered, and there is no lack of interest groups who understand the value of such alteration. By changing cultural norms, they can change how the average person thinks and behaves.

References

Cumings, B. (1982-1983). Corporatism in North Korea, Journal of Korean Studies, 4, 269-294.

Koehler, R. (2006). I guess this means the DPRK won’t be inviting Hines Ward for a visit (English translation of Rodong Sinmun editorial).
http://www.rjkoehler.com/2006/04/27/i-guess-this-means-the-dprk-wont-be-inviting-hines-ward-for-a-visit/

Korea Central News Agency (2006). Rodong Sinmun Censures Theory of "Multiracial Society" http://kcna.co.jp/item/2006/200604/news04/28.htm#7

Myers, B.R. (2010). The Cleanest Race: How North Koreans See Themselves—and Why It Matters, Brooklyn: Melville House.

South Korea abolishes itself

2011-09-24T10:25:00.003-05:00

“Global Korea” poster. Has South Korea become the new posterboy for globalism?

East Asia has been an outlier in the developed world. Like Western Europe and North America, it is integrated into the global economy and enjoys a high standard of living. This is particularly so for the original five ‘tigers’: Japan, South Korea, Taiwan, Hong Kong, and Singapore.

Yet East Asia has bucked the trend toward loss of nationhood. Its governments still see their role as one of perpetuating a specific ethnic identity and cultural tradition. This is in contrast to the view, dominant in the West, that countries should simply be administrative units and should interfere as little as possible in the free flow of capital, goods, and labor.

Recently, this outlier has lost one member. South Korea is falling into line with the globalist paradigm and has opened its borders to increasingly higher rates of immigration:

As of 2007, 1,066,291 registered foreigners were residing in South Korea. More than 400,000 migrant workers are now working in so-called 3-D [Dirty, Dangerous, and Difficult] industries where South Koreans are reluctant to work. 110,362 immigrants entered in 2007 to marry South Korean husbands or wives and the cumulative number of international marriages increased to 364,000 during the 1990-2007 period. In 2005, 13% of all marriages in South Korea were interracial or interethnic marriages and the rate of international marriages was even higher in rural areas where about one-third of all marriages were interracial or interethnic. (Yoon et al., 2008)

When immigration began in the late 1980s, the aim was to ease labor shortages and offset a perilously low birth rate while maintaining the ethnic status quo. Diaspora Koreans would be repatriated from China and the former Soviet Union, and North Korean defectors would be welcomed. This aim was quietly set aside from the mid-1990s onward, as the zone of recruitment broadened to include the Philippines, Vietnam, Indonesia, Bangladesh, Sri Lanka, Pakistan, and even countries as far afield as Nigeria (Kim, 2004). Today, South Korea is entering uncharted waters of demographic change:

[…] South Korean society has entered the first phase of multiethnic and multicultural society and the current process seems irreversible. If the current trend continues, the proportion of foreigners residing in South Korea will increase to 2.8% in 2010, 5% in 2020, and 9.2% in 2050 (Yoon et al., 2008)

The increase may actually be greater. On the one hand, the declining birth rate shows no signs of bottoming out. On the other, once immigrant communities become established, they tend to facilitate more immigration from their home countries, whether legal or illegal. It is worth noting that the above figures exclude illegal immigrants, who are estimated to form half the total intake (Moon, 2010).

Will this demographic change meet growing resistance from the public? Not in the near future. If anything, public opinion has been moving in the other direction. Between two surveys, taken in 2003 and 2007, the shift in opinion was remarkable:

For example, to the statement "It is impossible for people who don' t share South Korean traditions and customs fully to become South Korean", 55% of the respondents agreed while 23% disagreed in 2003, but in 2007 30.8% of the respondents agreed while 32.9% disagreed. (Yoon et al., 2008)

There has also been an increase in hostility to public meetings of “ people prejudiced against racial and ethnical groups.” In 2004, 29.6% of respondents felt such meetings “should definitely not be allowed.” By 2007, the figure had risen to 46.5% (Yoon et al., 2008).

Multiculturalism is thus becoming a core value, like filial piety of another age. By adhering to it, South Koreans earn respect not only from their friends and colleagues but also from themselves. This conformity seems to reflect a longstanding desire in Korean culture to comply with social norms.

Will there be resistance from the political elites? Again, not in the near future. Although multiculturalism is often identified with the Left, the new policy of “Global Korea” is actually being pushed by the Right, specifically the Grand National Party (GNP):

For the conservative government, South Korean nationalism and democracy is fundamentally tied to the doctrine of neo-liberalism. Neo-liberalism refers to the flow of economic migrant labour and mobile global capital. This global environment also requires government policies to attract foreign migrants and workers into South Korea’s economy and society.

Multiculturalism is a state-led response to these global changes. The policies of multiculturalism define the present and future economic, security and cultural national strength of South Korea. Critics suggest that, in fact, the GNP regards multiculturalism as an instrumental policy of increasing national state power in this global environment. (Watson, 2010)

South Korea has entered what may be called ‘late’ or ‘mature’ capitalism. The business community has emancipated itself from the nation state and is now willing to enrich itself at the expense of its host society, notably by outsourcing employment to lower-wage countries and by “insourcing” lower-wage labor. To this end, its political spokesmen borrow leftwing discourse to create an artificial Left-Right consensus. As Watson (2010) goes on to argue:

The Right has effectively ‘‘stolen’’ the language of the Left (which has traditionally promoted multiculturalism) and colonised the language of multiculturalism with nationalism and security languages and concerns. For the Left, by ideologically separating multiculturalism from economic globalisation and its economic and political inequalities, multiculturalism becomes a quaint cosmopolitan smokescreen covering economic and political hardships.

One might add that the Right has likewise colonized the language of nationalism with multicultural concerns. The push is on to equate Korean nationality with residence on Korean soil. This concept of citizenship is now being taught in South Korean schools:

Mono-ethnicism was not officially removed from K-12 social studies and moral education textbooks until February, 2007. For example, social studies textbooks for sixth graders used to mention that “Korea consists of one ethnic group. We, Koreans, look similar and use the same language” (Mo, 2009). Citizenship education was grounded in this mono-ethnicism, and the national curriculum focused on enhancing democratic citizenship, including obedience to the law, rights as citizens, morality, and loyalty to the nation (Yang, 2007).

[…] The Korean government has acknowledged dramatic social changes in contemporary Korean society and has attempted to implement this view of contemporary Korean society in national curriculum standards. National curriculum standards have replaced mono-ethnicism with the notions of cultural diversity and multiculturalism. (Moon, 2010)

In this, the South Korean government appears to have also acted under pressure from foreign organizations, notably the United Nations:

Mainstream Korean citizens used to believe that Korea consists of “one-blood, one-language, and one-culture.” The Convention on the Elimination of Racial Discrimination (CERD) in the United Nations (UN) has pointed out that the “pure-blooded” ideology and the notions of ethnic homogeneity have resulted in various forms of discrimination in Korea (Wagner, 2009). CERD has recommended recognizing the multi-ethnic character of contemporary Korean society and promoting understanding, tolerance, and friendship among the different ethnic and national groups in Korea. In education, CERD has recommended that the Korean government include human rights awareness programs in the official curriculum. A revised curriculum should describe a Korean society in which people from multiple ethnic and cultural backgrounds live together harmoniously (Hong, 2008; Wagner, 2009). (Moon, 2010)

Why South Korea?

Why is this shift to globalism stronger in South Korea than in other East Asian countries? The likeliest answer is the country’s special relationship with the United States.

This relationship goes far beyond the current stationing of U.S. troops along the demilitarized zone. When South Korea was freed from Japanese rule in 1945, the Americans were greeted as liberators—in contrast to Japan, where they were merely accepted as occupiers. Even today, there is a legacy of pro-American sentiment that has few parallels elsewhere in East Asia.

As liberators, the Americans were able to create a new political class from scratch. The Japanese had forced into exile much of the native leadership, and these émigrés were now brought home to form a government under U.S. auspices. One of them was the first president of South Korea, Syngman Rhee, a man who had spent most of his adult life in the United States. A similar situation existed in North Korea, where the new government was made up largely of émigrés from China and the Soviet Union.

To some degree, this situation still prevails. Political and economic leaders are often graduates of American universities, and they tend to see the U.S. as a model to be followed. Furthermore, this model cannot be easily criticized because such criticism may be seen as sympathy for the communist North.

References

Choi, J. (2010). Educating Citizens in a Multicultural Society: The Case of South Korea, The Social Studies, 101, 174–178.

Kim, W-B. (2004). Migration of foreign workers into South Korea: from periphery to semi-periphery in the global labor market, Asian Survey, 44, 316-335.

Moon, S. (2010). Multicultural and Global Citizenship in the Transnational Age: The Case of South Korea, International Journal of Multicultural Education, 12, 1-15.

Watson, I. (2010). Multiculturalism in South Korea: A Critical Assessment,
Journal of Contemporary Asia, 40, 337-346

Yoon, I-J.,Y-H. Song, Y-J. Bae. (2008). South Koreans' Attitudes toward Foreigners, Minorities and Multiculturalism, Paper prepared for presentation at the annual meeting of the American Sociological Association, Boston, MA from August 1-4, 2008.

No, they aren't pure either

2011-09-17T11:55:00.004-05:00

Broken Hill skull from Zambia, dated to 110,000 BP. It is often identified as a Homo sapiens, largely because it is so recent. We now have evidence that very archaic hominins inhabited central and southern Africa at least 35,000 years ago.

The past year has brought us a new model of human evolution. It’s a modified version of “Out of Africa.” Present-day humans are now traced to a small founder group that began to expand some 80,000 years ago in East Africa and started to spread out of Africa some 50,000 to 40,000 years ago. Meanwhile, these early modern humans intermixed to varying degrees with the archaic hominins they replaced. There is thus 1 to 4% Neanderthal admixture in present-day Europeans and Asians, and 8% Neanderthal and “Denisovan” admixture in Melanesians (Green et al., 2010; Reich et al., 2010).

What about Africans? Are they the only “pure” humans? This is unlikely on theoretical grounds, as Hammer et al. (2011) point out in a newly released paper:

[…] the greatest opportunity for introgression was in Africa, where AMH [anatomically modern humans] and various archaic forms coexisted for much longer than they did outside of Africa. Indeed, the fossil record indicates that a variety of transitional forms with a mosaic of archaic and modern features lived over an extensive geographic area from Morocco to South Africa between 200 and 35 kya.

Africa’s warm climate tends to break down DNA quite rapidly. So we’ll probably never get to reconstruct an archaic African genome from a tooth or a skeletal fragment. But we can look through modern African genomes for signs of introgression from an archaic source. The most telltale signs are unusual polymorphisms in noncoding regions.

Using this approach, Hammer et al. (2011) assign about 2% of the modern African genome to an archaic population that split from ancestral modern humans some 700,000 years ago. This admixture is dated to about 35,000 years ago and may have occurred in Central Africa, since the level of admixture is highest in pygmy groups from that region.

Who exactly were these archaics?

Beginning ≈700 kya, fossil evidence from many parts of Africa indicate that Homo erectus was giving way to populations with larger brains, a change that was accompanied by several structural adjustments to the skull and postcranial skeleton (14). By ≈200 kya, individuals with more modern skeletal morphology begin to appear in the African record (8, 14). Despite these signs of anatomical and behavioral innovation, hominins with a combination of archaic and modern features persist in the fossil record across sub-Saharan Africa and the Middle East until after ≈35 kya […] Interestingly, recent studies attest to the existence of Late Stone Age human remains with archaic features in Nigeria (Iwo Eleru) and the Democratic Republic of Congo (Ishango) (Hammer et al., 2011)

Did Homo erectus linger in parts of Africa until as late as 35,000 years ago? The idea is no longer science fiction. We have the example of the “hobbits”—a Homo erectus population that lasted at least as long in Southeast Asia.

Perhaps we should take a second look at the Broken Hill skull, which was found near Kabwe, Zambia and has been dated to 110,000 BP (Bada et al., 1974). Many anthropologists have raised it to sapiens status, largely on the assumption that non-sapiens were no longer around at that time. Yet it doesn’t look at all like a Homo sapiens.

Admixture with late archaics

Broken Hill man probably occupied one end of a range of archaic groups that inhabited Africa on the eve of the ‘big bang’—the demic expansion of early modern humans that began 80,000 years ago somewhere in East Africa. At the other end were late archaic hominins who looked just like early modern humans but still lacked some of the final changes to their neural wiring.

If sub-Saharan Africans have about 2% admixture from Homo erectus, they probably have much more from late archaic hominins, who were more numerous and behaviorally more similar. How great is this late archaic admixture?

According to Watson et al. (1997), about 13% of the sub-Saharan gene pool comes from a demic expansion c. 111,000 years ago that corresponds to the entry of Skhul-Qafzeh hominins into the Middle East. Although these hominins were almost anatomically modern, their technology was Mousterian and differed little from that of Neanderthals.

Some last-minute neural changes seem to have occurred between this expansion 111,000 years ago and the ‘big bang’ 80,000 years ago. Perhaps these changes triggered the second expansion. As Atkinson et al. (2009) write:

[…] the African exodus was predated by a cultural revolution involving new stone blade technologies, skin working tools, ornaments and imported red ochre […] More advanced symbolic systems in language and religious beliefs could have provided a competitive advantage to a group by promoting coordination and cohesion.

What does it all mean?

It’s interesting that we have varying degrees of archaic admixture. But what does it all mean? Did these different admixtures make us different in different ways?

A traditional evolutionist would answer ‘no.’ As Ernst Mayr (1970, p. 80) wrote:

The claim has been made that species owe much of their genetic variability to introgressive hybridization. However, all the evidence contradicts this conclusion so far as animals is concerned. Not only are F1 hybrids between good species very rare, but where they occur the hybrids (even when not sterile) are demonstrably of inferior viability. The few genes that occasionally introgress into the parental species are not coadapted […] and are selected against. Introgressive hybridization seems to be a negligible source of genetic variation in animals.

In opposition to this view, Greg Cochran and John Hawkes have argued that gene introgression enabled early modern humans to adapt more quickly to new environments. Instead of starting from scratch, they just ‘cherry-picked’ genes that had already been developed by the populations they were replacing.

All of this assumes there were cherries worth picking. Did archaic hominins have anything useful to offer? Modern humans and Neanderthals adapted to the same cold environment but they did so in very different ways. The former, for instance, made tailored clothing while the latter were probably as furry as bears.

The stage whisper is that the Neanderthals gave ancestral Europeans special brain genes, notably the latest microcephalin variant (Hawkes et al., 2008). We now know otherwise. The reconstructed Neanderthal genome has revealed no brain genes that our ancestors cherry-picked. As for African archaic hominins, it’s even less clear what they had to offer. These were groups that lived under similar climatic and ecological conditions.

The cherry-picking theory seemed like a great idea. How else could one explain the sudden cultural dynamism of early modern humans? This effervescence began only 30,000 to 20,000 years ago—long after the ‘big bang.’ And it was most evident in southwestern France—a place far from East Africa. Surely the simplest explanation is gene introgression from European Neanderthals.

Well, things are never as simple as they seem. There are in fact other explanations:

1. Southwestern France has provided so many early European artifacts in part because it had so many early Europeans. It benefited from an unusually rich environment that could support a large population of semi-sedentary hunter/fisher/gatherers (Mellars, 1985).

2. France is a country with strong grassroots interest in history and prehistory. This is unfortunately not so elsewhere in the world, where the remote past is often viewed with indifference. Why does so much of our knowledge of the prehistoric Middle East come from Israel? Because Israel is chock-full of archeologists who do their work passionately and, in many cases, for free. We view human prehistory through the lens of present-day interests.

3. Actually, there is evidence of technological complexity almost at the epicenter of the ‘big bang.’ Central African sites have yielded fine tools, dated to c. 90,000 BP, that look just like Aurignacian tools from post-Neanderthal Europe (Brooks et al., 1995; Yellen et al., 1995).

References

Atkinson, Q.D., R.D. Gray, and A.J. Drummond. (2009). Bayesian coalescent inference of major human mitochondrial DNA haplogroup expansions in Africa, Proceedings of the Royal Society B, 276, 367–373

Bada, J.L., R.A. Schroeder, R. Protsch, & R. Berger. (1974). Concordance of Collagen-Based Radiocarbon and Aspartic-Acid Racemization Ages, Proceedings of the National Academy of Sciences (USA), 71, 914-917.

Brooks, A.S., D.M. Helgren, J.S. Cramer, A. Franklin, W. Hornyak, J.M. Keating, R.G. Klein, W.J. Rink, H. Schwarcz, J.N. Leith Smith, K. Stewart, N.E. Todd, J. Verniers, & J.E. Yellen. (1995). Dating and context of three Middle Stone Age sites with bone points in the Upper Semliki Valley, Zaire, Science, 268, 548-553.

Green, R.E., J. Krause, A.W. Briggs, T. Maricic, U. Stenzel, M. Kircher, et al. (2010). A draft sequence of the Neandertal genome, Science, 328, 710-722.

http://www.sciencemag.org/cgi/reprint/328/5979/710.pdf

Hammer, M.F., A.E. Woerner, F.L. Mendez, J.C. Watkins, and J.D. Wall. (2011). Genetic evidence for archaic admixture in Africa, Proceedings of the National Academy of Science (USA), early edition, www.pnas.org/cgi/doi/10.1073/pnas.1109300108

Hawks, J., G. Cochran, H.C. Harpending, & B.T. Lahn (2008). A genetic legacy from archaic Homo, Trends in Genetics, 24, 19-23.

Mayr, E. (1970). Populations, Species, and Evolution, Belknap Press: Cambridge (Mass.)

Mellars, P.A. (1985). The ecological basis of social complexity in the Upper Paleolithic of Southwestern France. In Prehistoric Hunter‑Gatherers. The Emergence of Cultural Complexity, T.D. Price & J.A. Brown (Eds.). Orlando: Academic Press, pp. 271‑297.

Reich, D., R.E. Green, M. Kircher, J. Krause, N. Patterson, E.Y. Durand, et al. (2010). Genetic history of an archaic hominin group from Denisova Cave in Siberia, Nature, 468, 1053-1060.

Watson, E., P. Forster, M. Richards, and H-J. Bandelt. (1997). Mitochondrial footprints of human expansions in Africa, American Journal of Human Genetics, 61, 691-704.

Yellen, J.E., A.S. Brooks, E. Cornelissen, M.J. Mehlman, & K. Stewart. (1995). A Middle Stone Age worked bone industry from Katanda, Upper Semliki Valley, Zaire, Science, 268, 553-556.

Did the slave trade make Africans polygynous?

2011-09-10T09:55:00.004-05:00

Slave exports to the Americas from different parts of Africa (Dalton & Leung, 2011). Did the slave trade create patterns of behavior that today exist throughout sub-Saharan Africa, such as generalized polygyny?

Why is polygyny so frequent in sub-Saharan Africa? As Goody (1973, p. 177) noted, the differences with Eurasia are striking:

In Europe and Asia, polygyny is largely but not exclusively an heir-producing device; often it is a way of replacing a barren wife. In Africa, plural marriage is far more generalised; according to Dorjahn, about 35 per cent of married men have more than one wife. Hence a large percentage of the population is likely to be part of a polygynous unit at some point in the life-cycle. Most men will be polygynously married at some time or other; women are yet more likely to be so. And most siblings will have sets of half siblings, both because of the plural marriage of their fathers and because of the remarriage of their mothers — since polygyny inevitably involves a large differential in the age of marriage, men will be older when they beget children than women are when they bear them. Hence there will be a higher proportion of widows and fatherless children.

Goody (1973) attributes this generalized polygyny partly to female self-reliance in food production. Year-round farming enables women to provide for their own needs and those of their children. A wife thus costs little in terms of upkeep, and this low maintenance cost encourages men to have as many wives as possible.

This rule nonetheless has interesting exceptions. In the savannah regions of Ghana, women plant grain and help with the harvest, but they leave yam cultivation to men and do not engage in hoeing for cereal agriculture. Yet polygyny rates are somewhat higher there than elsewhere in Ghana, where women contribute more to food production. Polygyny is also less frequent in East Africa than in West Africa, yet women contribute more to food production in East Africa than in West Africa.

Goody (1973, p. 185) concludes that “hoe agriculture, female farming and polygyny are clearly associated in a general way” but there must be other explanatory factors. But what?

For Dalton and Leung (2011), one big factor is the slave trade—the mass exportation of African laborers that ended only two centuries ago. West Africa tended to export male slaves while East Africa tended to export female slaves. This pattern reflected differences in market demand: on the one hand, the Americas wanted farm labor; on the other, the Middle East and South Asia wanted domestics or concubines. These differing sex ratios might therefore explain why polygyny is less frequent in East Africa than in West Africa:

The slave trades existed for hundreds of years, and, as a result, Africa experienced abnormal sex ratios for long periods of time. Polygyny could have emerged or been strengthened during the long period of abnormal sex ratios. Figures 1 and 2 suggest the Western Coast should have contained more polygynous marriages, whereas the Eastern Coast should have contained fewer.

These abnormal sex ratios returned to normal once the slave trade had ended in the early 19th century. Why, then, didn’t polygyny rates follow this return to normal? Dalton and Leung (2011, p. 8) blame cultural conservatism: “Once these cultural traits are established, polygyny can become self-sustaining.”

This hypothesis is interesting and might explain some of the variation in polygyny rates within sub-Saharan Africa. But it fails to explain why polygyny rates are in the double-digit range throughout sub-Saharan Africa. East Africa’s rates are lower but still high by world standards. Goody (1973, p. 181) states that East African cattle societies have a rate of 24.7%, i.e., the percentage of married men with more than one wife. Pebley and Mbugua (1989) similarly write: “The frequency is somewhat lower in East and South Africa, although 15 to 30 percent of husbands are reported to be polygynists in Kenya and Tanzania.”

Admittedly, the above figures run counter to the ones offered by Dalton and Leung (2011, p. 1):

[…] the percentage of men in polygynous marriages in Western African countries like Guinea, Togo, and Benin is 35.037, 29.793, and 29.679, whereas in Eastern African countries like Ethiopia, Kenya, and Malawi the percentage is 6.131, 9.206, and 10.101.

These figures come from the latest “Demographic and Health Surveys” and are twenty to forty years more recent than the other figures. As such, they reflect the decline in female farming and the growing urbanization of African societies. In this new context, institutionalized polygyny has given way to looser arrangements with multiple girlfriends and/or prostitutes. And why bring Ethiopia into the comparison? It is not a sub-Saharan country and differs from both West and East Africa in many ways, notably the long-established influence of the Coptic Church and Christian sexual norms.

Dalton and Leung also err in assuming that sub-Saharan Africa had low polygyny rates before the slave trade. Several lines of evidence argue otherwise:

1. The ratio of Y-chromosome to X-chromosome variability is much higher among sub-Saharan Africans, New Guineans, and Aboriginal Australians than among other human populations. This suggests a long-lasting trend of fewer men than women contributing to the gene pool (Dupanloup et al., 2003; see also Torroni et al., 1990; Scozzari et al., 1997).

2. Proto-Bantu, spoken approximately 3,000 years ago, has a specific term for “taking a second wife” (Polome, 1977).

3. A high level of male-male competition for females is suggested by the increased sexual dimorphism of African Americans for weight, chest size, arm girth, and leg girth (Todd & Lindala, 1928; Wolff & Steggerda, 1943). In contrast, a small, gracile, and almost childlike body characterizes Khoisans and Pygmies, the only sub-Saharan populations with low polygyny rates.

After arguing that the slave trade caused generalized polygyny, Dalton and Leung see therein a leading cause of Africa’s lag in economic and social development.

Among similar countries, polygynous countries are poorer than nonpolygynous countries. Polygynous countries have higher fertility and lower savings. The calibrated model in Tertilt (2005) suggests banning polygyny decreases fertility by 40 percent, increases savings by 70 percent, and increases GDP per capita by 170 percent. (Dalton & Leung, 2011, p. 3)

There is undoubtedly some kind of relationship between generalized polygyny and Africa’s stubbornly high fertility and economic poverty, but it’s not a simple one of cause and effect. Banning polygyny will not cause immediate changes to reproductive and economic behavior. Dalton and Leung themselves argue that cultural conservatism alone has maintained high polygyny rates in Africa for the past two centuries. Wouldn’t the same be true for other behaviors?

Remember also that the time depth of generalized polygyny is not the four or five centuries that Dalton and Leung claim. In sub-Saharan Africa, high polygyny rates are associated with ‘female farming’ societies, and such societies began to spread outward from a point of origin near the Niger’s headwaters some 6,000 to 7,000 years ago (Murdock, 1959, pp. 44, 64-68).

Behavioral predispositions have significant heritability, especially in relation to sexual behavior (Comings et al., 2002; Mendle et al., 2006; Belsky et al., 2007). If generalized polygyny has existed in sub-Saharan Africa for six to seven thousand years, wouldn’t it have favored certain predispositions and not others? And wouldn’t those predispositions survive the banning of polygyny?

The question doesn’t seem to have crossed the authors’ minds. They seem to believe, a bit naïvely, that there is only cultural conservatism to worry about. No less naïve are the authors they cite:

Nunn and Wantchekon (2010) examines a particular channel through which the slave trades impact current African economic performances, namely the levels of trust across individuals within Africa. Trust supports economic exchange in well-functioning markets and would have plausibly been affected within groups living in the capture and export economies participating in the slave trades. Nunn and Wantchekon (2010) shows those individuals whose ancestral groups experienced higher slave exports exhibit lower levels of trust even to this day. Our paper contributes to these findings by suggesting an additional channel through which the slave trades have had a long-term impact on current African society. (Dalton & Leung, 2011, p. 2)

Low trust is typical of all simple, clan-based societies. Papua-New-Guinea was not affected by the slave trade, yet it has very low levels of trust. The slave trade may indeed have made people less trusting in some parts of sub-Saharan Africa than in others. But this does not explain why levels of trust are so low in sub-Saharan Africa as a whole.

And questions can be raised about the study by Nunn and Wantchekon (2010). Those authors found that willingness to trust members of other ethnic groups correlated with an ethnic group’s historical importance as a source of slaves. Most slaves, however, were taken during inter-tribal wars, and such wars generally occurred in regions already prone to interethnic conflict.

In short, the correlation is valid, but it doesn’t prove the causal relationship that Nunn and Wantchekon infer. In fact, the line of causality probably runs in the opposite direction.

References

Belsky, J., L.D. Steinberg, R.M. Houts, S.L. Friedman, G. DeHart, E. Cauffman, G.I. Roisman, B.L. Halpern-Felsher. (2007). Family rearing antecedents of pubertal timing, Child Dev., 78, 1302-1321.

Comings, D.E., D. Muhleman, J.P. Johnson, J.P. MacMurray. (2002). Parent-daughter transmission of the androgen receptor gene as an explanation of the effect of father absence on age of menarche. Child Dev., 73, 1046-1051.

Dalton, J.T., & T.C. Leung. (2011). Why is Polygyny More Prevalent in Western Africa?
An African Slave Trade Perspective,

http://www.wfu.edu/~daltonjt/PolygynySlaveTrade.pdf

Demographic and Health Surveys (2011): www.measuredhs.com

Dupanloup, I., L. Pereira, G. Bertorelle, F. Calafell, M.J. Prata, A. Amorim, & G. Barbujani. (2003). A recent shift from polygyny to monogamy in humans is suggested by the analysis of worldwide Y-chromosome diversity. Journal of Molecular Evolution, 57, 85-97.

Goody, J. (1973). The Character of Kinship, Cambridge: Cambridge University Press.

Mendle, J. E. Turkheimer, B.M. D’Onofrio, S.K. Lynch, R.E. Emery, W.S. Slutske, & N.G. Martin. (2006). Family structure and age at menarche: a children-of-twins approach, Dev Psychol., 42, 533-542.

Murdock, G.P. (1959). Africa. Its Peoples and Their Culture History. New York: McGraw-Hill.

Nunn, N., & L. Wantchekon. (2010). The Slave Trade and the Origins of Mistrust in Africa, American Economic Review, forthcoming.

Pebley, A. R., & W. Mbugua. (1989). Polygyny and Fertility in Sub-Saharan Africa. In R. J. Lesthaeghe (ed.), Reproduction and Social Organization in Sub-Saharan Africa, Berkeley: University of California Press, pp. 338-364.

Polome, E.C. (1977). The reconstruction of Proto-Bantu culture from the lexicon. In L. Bouquiaux (Ed.) L'Expansion bantoue, 2, 779-791. Centre national de la recherche scientifique.

Scozzari, R., F. Cruciani, P. Malaspina, P. Santolamazza, B.M. Ciminelli, A. Torroni, D. Modiano, D.C. Wallace, K.K. Kidd, A. Olckers, P. Moral, L. Terrenato, N. Akar, R. Qamar, A. Mansoor, S.Q. Mehdi, G. Meloni, G. Vona, D.E.C. Cole, W.W. Cai, & A. Novelletto. (1997). Differential structuring of human populations for homologous X and Y microsatellite loci. American Journal of Human Genetics, 61, 719-733.

Todd, T.W. & A. Lindala. (1928). Dimensions of the body: Whites and American Negroes of both sexes. American Journal of Physical Anthropology, 12, 35-101.

Torroni, A., O. Semino, R. Scozzari, G. Sirugo, G. Spedini, N. Abbas, M. Fellous, et al. (1990). Y-chromosome DNA polymorphisms in human populations: differences between Caucasoids and Africans detected by 49a and 49f probes. Annals of Human Genetics, 54, 287-296.

Wolff, G. & M. Steggerda. (1943). Female-male index of body build in Negroes and Whites: An interpretation of anatomical sex differences. Human Biology, 15, 127-152.

Whither evolutionary psychology?

2011-09-03T13:35:00.003-05:00

Is groupthink genetically determined? Twin studies suggest that people are prewired to identify and comply with social rules.

Where to from here? Will evolutionary psychology ossify and disappear? Or will it redefine itself and move on?

In a sense it doesn’t matter. A name is just a name, and the field of evolution and human behavior has had other names. The main issue is whether the current name is a help or a hindrance. Will it allow change from within?

Bolhuis et al. (2011) think so. In their call for a new evolutionary psychology, they have made several recommendations. One is to accept the reality of gene-culture co-evolution. In short, we should pick up where research petered out some two decades ago.

Amongst the overrepresented categories in genome-wide scans of recent selection are numerous alleles expressed in the human nervous system and brain. This raises the possibility that complex cognition on which culture is reliant (social intelligence, language, and challenges associated with constructing and adapting to new environmental conditions) have driven human brain evolution. Mathematical models exploring how genetic and cultural processes interact provide strong support for the role of gene-culture coevolution in human evolution.

Evolutionary psychologists should reconsider their assumption of a universal human nature. “For example, sex differences in mate preferences constitute a large proportion of EP research and are generally assumed to exhibit universal patterns.” Yet sex roles assume different forms in different human populations.

Another recommendation is to bridge the gap between postulated “psychological mechanisms” and actual neurons. We now have tools, notably MRI, that can locate where a specific mental activity occurs in the brain. Again, such research should take variation within and between human populations into account and not be confined to the usual participant pool of North American university students.

Finally, evolutionary psychologists should stop assuming that the human mind consists mainly of domain-specific programs. Much of our thinking is, in fact, domain-general.

Uh, what is ‘domain-general’? Think of a computer program that has plenty of sections or variables left blank. The blanks can be filled in with information, thus enabling the same kind of program to do a wide range of tasks. We call this in-filling process ‘learning.’

Learning thus takes place via programs that have already been partly hardwired. This is why we can learn some things better than others. There are also constraints on how fast we can learn, how much we can learn, and on how easily we can integrate learned information. Learning is not the opposite of genetic determinism. The two concepts are complementary.

By minimizing the role of learning, evolutionary psychologists not only lose the high ground of credibility but also give a free hand to those who say that humans can learn to think anything. A good example is the debate over social rules:

EP has engaged in a longstanding debate with advocates of cultural evolution over whether human social learning is governed by evolved content biases (e.g., choose the sugar-rich food) or by domain-general context biases (e.g., conform to the local norm). There is sufficient empirical evidence for the deployment of context biases, such as conformity or prestige bias, to render the casual dismissal of transmitted culture counterproductive. (Bolhuis et al., 2011)

Groupthink is a reality, and its persistence in modern societies should make it ideal for EP research. One puzzle of twin studies is the relatively high heritability of religious fundamentalism. Among twins reared apart, 40-46% of the variance seems to be genetic in origin (DiLalla et al., 1996). Perhaps there has been natural selection for humans who can more easily identify and comply with social rules, thus sparing themselves the pain of learning them the hard way.

This point is worth investigating because willingness to comply with rules varies from one individual to another, and from one population to the next. Some people have an unusually high level of rule compliance. Why? Is it learned or innate? Or a bit of both?

Some evolutionary psychologists have actually been moving in this direction. Denise Cummins (1998, p. 37) describes mental evolution as “a strategic arms race in which the weaponry is ever-increasing mental capacity to represent and manipulate internal representations of the minds of others.” In addition to ‘indicative reasoning’ (what is true or false), humans have a capacity for ‘deontic reasoning’ (what is permitted, obligated, or forbidden). For deontic rules, people look for examples of violations. For indicative rules, people look for examples of proof.

In short, indicative rules are subject to change, as people learn more about their environment. Deontic rules are not so easily changed. The latter generally change with a new class of higher-status individuals, who not only are the preferred source of deontic rules but are also seen as being above the rules. Thus, people more easily remember cheaters than non-cheaters, but this memory is weaker when the cheaters are high-status individuals (Mealey, Daood, & Krage, 1996).

All of this raises a problem for the Pleistocene EEA. Hunter-gatherer societies have little if any social stratification. The same is largely true for simple agricultural societies. The ‘big man’ is not a force for social stability and rule making. His dominance is transient, lasting as long as his strength, charisma, and ability to intimidate.

Societies became stratified only during the last 10,000 years. This time also saw the beginnings of lawmaking, codified morality, and organized religion. Of course, there is no reason why these phenomena could not have influenced human nature via gene-culture co-evolution. The last 10,000 years have seen more genetic evolution than the previous 100,000 … or even the previous million.

But to say so is anathema to those who still believe that the human mind stopped evolving over a million years ago.

References

Bolhuis, J.J., G.R. Brown, R.C. Richardson, and K.N. Laland. (2011). Darwin in mind: New opportunities for evolutionary psychology, PLoS Biol 9(7): e1001109. doi:10.1371/journal.pbio.1001109
http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001109

Cummins, D.D. (1998). Social norms and other minds: The evolutionary roots of higher cognition. In D.D. Cummins & C. Allen (eds.) The Evolution of Mind (pp. 30-50). New York: Oxford University Press.

DiLalla, D.L., G. Carey, I.I. Gottesman, and T.J. Bouchard Jr. (1996). Heritability of MMPI personality indicators of psychopathology in twins reared apart, Journal of Abnormal Psychology, 105, 491-499.

Mealey, L., C. Daood, & M. Krage. (1996). Enhanced memory for faces of cheaters, Ethology and Sociobiology, 17, 119-128.

Was evolutionary psychology inevitable?

2011-08-27T11:21:00.006-05:00

Cover of Time, August 28, 1995. Evolutionary psychology beat out its rivals in the race to win public acceptance.

During the 1990s, evolutionary psychology overtook and replaced sociobiology. Its success was total, much like that of many paradigms we now accept as normal science. Did it succeed for the same reason? Did it better fit the data?

In some ways evolutionary psychology was better than its rivals and in other ways worse. Its superiority tended to be more organizational, even political. In short, it became the only game in town for study of human behavior from an evolutionary perspective. The alternatives—sociobiology and gene-culture co-evolution—had much less to offer in terms of research funding, career opportunities, or just an untroubled academic life.

Early years of evolutionary psychology

At first, the term ‘evolutionary psychology’ simply referred to psychologists and psychiatrists who shared an interest in evolutionary theory. Such people began to come together in the late 1980s:

In mid-1987, an initial list of people using modern evolutionary theory to address problems in psychology and psychiatry was compiled and distributed. The respondents suggested additional names that expanded the list to over 200 researchers. Many people expressed surprise that there were so many others working in the area. Many more suggested that it was time to organize a forum for the exchange of ideas and research findings in the area. (Evolution, Psychology and Psychiatry 1988)

The first forum was held at the 1988 Evolution and Human Behavior Meeting in Ann Arbor, Michigan. The meeting had two purposes:

- To facilitate the exchange of ideas and findings among researchers in the area of Evolution, Psychology and Psychiatry. The developing new basic science will be emphasized.

- To consider plans for initiating an organization that will promote research and scholarly exchange in the area of Evolution, Psychology and Psychiatry.

The proceedings only hinted at evolutionary psychology’s eventual divorce from sociobiology. Some presenters talked about a mismatch between current behavior and earlier contexts of adaptation, but these contexts were not placed over a million years ago in the Pleistocene.

It was decided to have more meetings and to hold them annually. The 1989 meeting, now called the Human Behavior and Evolution Conference, had a similar mix of ideas. Presenters were now talking more about ‘mismatch’ and ‘mental mechanisms’:

Debate about the relevance of mental mechanisms, rather than current human behavior, to the study of adaptation continued from other conferences in the recent past. […] Turke pointed out that studies examining current reproductive success could reveal the nature of mental mechanisms by comparing contexts in which humans do or do not behave adaptively. […] The abstract models presented by evolutionary psychologists (first by Cosmides and Tooby), which are somewhat like descriptive structural equation models, seem often to be misunderstood to present physiological structures, again making mental mechanisms appear to promote invariant behavior. More sophisticated basic theory is necessary to determine whether current behavior reflects adapted strategies. (HBES, 1990)

Leda Cosmides and John Tooby were already arguing that the genetic determinants of human behavior had assumed their current form long before the emergence of Homo sapiens, but this view was still a minority one. Other presenters were affirming the possibility of much more recent evolution:

Cultural versus natural selection was also the major topic of a roundtable on the final morning, lead by William Hamilton, George Williams, Irenaus Eibl-Eibesfelt, Edward Wilson, Irven DeVore, and Richard Dawkins. Much of the discussion focused on the unit of selection and the selective process. Dawkins stressed defining a specific replicating unit, which must be genes or memes. Williams proposed using epidemiological, disease–transmission models for the spread of cultural traits rather than using genetic models. Wilson stressed the importance of co-evolutionary theory, which models the interaction of genes and culture in epigenetic processes. (HBES, 1990)

Evolutionary psychology was nonetheless en route to becoming a paradigm distinct from sociobiology, with the Pleistocene EEA as the key difference. In 1989, this theme inspired two articles in Ethology and Sociobiology. Don Symons wrote:

[…] a well-formed description of an adaptation must consist solely of words for things, events, relations, and so forth that existed in the EEA, which, in the case of human beings, means the Pleistocene world of nomadic foragers. The specific environmental features to which Tibetan polyandry is adapted, according to Crook and Crook, include agricultural estates, animal husbandry, primogeniture, monasticism, aristocrats, landlords, governments, and taxation. Because none of these things existed in the human EEA, Crook and Crook’s account contains not a single well formed description of a Darwinian adaptation […] (Symons, 1989, pp. 138-139)

John Tooby and Leda Cosmides argued along similar lines:

It is no more plausible to believe that whole new mental organs could evolve since the Pleistocene—i.e., over historical time—than it is to believe that whole new physical organs such as eyes would evolve over brief spans. It is easily imaginable that such things as the population mean retinal sensitivity might modestly shift over historical time, and similarly minor modifications might have been made in various psychological mechanisms. However, major and intricate changes in innately specified information-processing procedures present in human psychological mechanisms do not seem likely to have taken place over brief spans of historical time. (Tooby & Cosmides, 1989, p. 34)

Here, Tooby and Cosmides assert that ‘whole new mental organs’ could not have arisen over the past million years. They then conclude that ‘major changes’ to mental organs are unlikely. This conclusion hardly follows from their initial assertion, which itself is doubtful. New organs have arisen over shorter time spans, specifically through duplication of an existing organ and rapid modification of the ‘spare.’

As a result of these articles and succeeding ones, the Pleistocene EEA came to define evolutionary psychology. The latter ceased to mean ‘sociobiology for psychologists’ and took on a narrower, more paradigmatic meaning.

Gene-culture co-evolution: a competing paradigm

At the turn of the 1990s, it was still far from clear that evolutionary psychology would take over from sociobiology. Gene-culture co-evolution seemed to hold a stronger position.

This other paradigm began in a cultural evolution class that L.L. Cavalli-Sforza taught in 1978-79 at Stanford to Robert Boyd and Peter Richerson (Stone & Lurquin 2005, p. 108). The Italian geneticist argued that the natural environment has not been the main driving force of human evolution. Instead, this role has largely fallen to the cultural environment, such as oral and written language, social organization, technology, means of subsistence, and so forth. There has thus been a feedback loop: we humans have created different cultural environments, which in turn have subjected us to different pressures of natural selection. Our creations have become our creators. This co-evolution fascinated Cavalli-Sforza, and its study now occupied his thoughts.

But others were thinking along the same lines, like the anthropologist Claude Lévi-Strauss in 1979:

[…] as anthropologists, the aspects of the question that will always appeal to us will be much less the genetic determination of culture or cultures than the cultural determination of genetics. […]

The selection pressure of culture—the fact that it favors certain types of individuals rather than others through its forms of organization, its ideas of morality, and its aesthetic values—can do infinitely more to alter a gene pool than the gene pool can do to shape a culture, all the more so because a culture’s rate of change can certainly be much faster than the phenomena of genetic drift. (Lévi-Strauss, 1979, p. 24-25)

The 1980s saw growing interest from other students of human evolution. Robert Boyd and Peter Richerson were among the first, followed by Pierre van den Berghe, Charles Lumsden, E.O. Wilson, and R.D. Alexander. The new paradigm was summed up by Pierre van den Berghe:

[…] the causality between genes and culture is reciprocal […] culture, though clearly possessing some emergent and irreducible properties (notably in its mode of transmission), is itself subject to a wide set of developmental parameters because it comes out of a brain with a definite bio-chemical structure […] the human mind, despite its undoubted plasticity, is not a tabula rasa. It is predisposed to learn certain things with ease, and others with difficulty or not at all. According to this viewpoint, the programmed learning biases of the human brain result in a non-random distribution of cultural products […] Moreover, since culture has consequences for the survival and reproduction of flesh and blood organisms, natural selection must exert some influence on cultural evolution (van den Berghe & Frost, 1986)

Work on gene-culture co-evolution initially involved trawling through the ethnographic literature. In the mid-1980s, however, a major project for field research was launched, specifically among the Inuit of northern Canada.

Its leader? Cavalli-Sforza. The project was organized in 1986 with professors from Queen’s University and Université Laval. The aim was to determine whether natural selection favors different mental toolkits in hunting and gathering societies versus agricultural societies. As one project member, John Berry, a psychologist at Queen’s University, later explained:

Hunters, by this way of thinking, require good visual acuity, keen disembedding skills and a well-developed sense of spatial orientation. To hunt successfully, the hunter must be able to discern the object of the quest (which is often embedded in a complex visual landscape), then disembed the object, and finally return to home base. In contrast, agriculturalists need not develop these particular skills, but rather they need to invest in other areas of development, such as conservation (in both the economic and the Piagetian senses) and close social interactions. (Berry 2008, p. 3)

According to an unpublished report, Cavalli-Sforza wished to trace the origins of Inuit artistic talent by estimating the relative contributions of genetic endowment and socio-cultural learning:

One of the most remarkable phenomena in the contemporary Canadian Arctic is the presence of highly-acclaimed art forms — carving in stone and ivory, and printing on paper. The question we ask is: how can we account for the wide-spread distribution of such talent in a small dispersed population?

[…] Is it possible that artistic talent is transmitted culturally (from parents to offspring, from others in society to the artist, and from peers to artist)? How can we assess these types of transmission?

Is it possible that artistic talent is transmitted genetically (from parents to offspring)? How can we assess such transmission? (Berry & Cavalli-Sforza 1986, p. 2)

The approach would be to study specific Inuit artists and then their biological and non-biological relatives. The high rate of adoption among Inuit (between 15 and 30%) would provide a means to distinguish cultural inheritance from genetic inheritance in the transmission of artistic talent. Related mental traits would also be investigated. “Given enough information one can hope to separately estimate two quantities, called respectively cultural and genetic heritability” (Berry & Cavalli-Sforza 1986, p. 5)

The project fell through. At Laval, we assumed something went wrong with the funding. At Queen’s, the story was that Cavalli-Sforza had quit because of illness. Yet his biography makes no mention of illness during this period, the only bouts of ill health being an operation for bladder cancer in 1976 and a heart attack in 1991 (Stone & Lurquin, 2005, pp. 98, 160). In any case, ill health would have been a reason for postponing the project, not canceling it.

This project has left no traces in any of Cavalli-Sforza’s publications—books, journal articles, conference proceedings, or poster sessions. The paper trail amounts to one unpublished report (Berry & Cavalli-Sforza, 1986). Just as mute are his published writings on gene-culture co-evolution. Examples are confined to the usual suspects: lactose tolerance in cattle-raising societies, and malaria resistance among tropical agriculturalists (Cavalli-Sforza & Cavalli-Sforza 2008, p. 264). There is no hint that natural selection might have favored different mental traits in different cultural environments.

Endgame

With Cavalli-Sforza gone, the field of gene-culture co-evolution lost momentum. It had big names, but few of them could put boots on the ground, i.e., do fieldwork. Nor could any of them focus on this area of research. As big names, they typically had their fingers in many pies.

There may have been another reason in the case of Cavalli-Sforza. He was vulnerable to blackmail because of his wartime anthrax research … in Berlin. Nothing terrible came of that laboratory work, but it had the potential to derail his career. At the very least, it was a stain on his curriculum vitae. (1)

Evolutionary psychology thus beat out its rivals by default. The term ‘sociobiology’ was becoming a mark of Cain even among people interested in human behavior and evolution. In 1997, it was literally voted out of existence. Gene-culture co-evolution continued to attract interest but only as a sideline.

With its rivals growing ever weaker, evolutionary psychology gained strength as the millennium drew nearer. It could now offer grad students a hassle-free research environment with a real chance of academic employment later on. This may have been due to avoidance of the stormy issue of population differences (although academia in general was becoming calmer). A bigger reason, however, was the strong focus of its main proponents, John Tooby and Leda Cosmides. They talked at conferences, gave interviews to the media, networked, and published, published, published. As they slowly climbed the academic career ladder, they would turn around to help likeminded people on lower rungs.

Bit by bit, they did what the big names could not do. They created a new teaching and research environment. And this environment would be called ‘evolutionary psychology.’

Note

1. Whenever Cavalli-Sforza lists his publications he never goes farther back than 1947. His wartime publications are all the more unknown because they were published under the name of Cavalli. He later changed his name to Cavalli-Sforza, having been ostensibly adopted by the second husband of his maternal grandmother. His autobiography dates the name change to 1950 (a year after his father died) when he was 28, married, and already a father. Such circumstances hardly justified adoption under Italian law or custom. Even more inexplicably, he was still publishing under his old name as late as 1953. Google Scholar lists three publications by L.L. Cavalli in 1950, one in 1951, five in 1952, and two in 1953.

References

Berry, J.W., and L.L. Cavalli-Sforza. (1986). Cultural and genetic influences on Inuit art. Report to Social Sciences and Humanities Research Council of Canada, Ottawa.

Boyd, R. and P.J. Richerson. (1985). Culture and the Evolutionary Process, Chicago: Chicago University Press.

Cavalli-Sforza, L.L. and F. Cavalli-Sforza (2008). La génétique des populations : histoire d'une découverte, Paris: Odile Jacob. (French translation of Perché la scienza : L’aventura di un ricercatore).

Evolution, Psychology and Psychiatry. (1988). Meeting Announcement, Ann Arbor, Michigan, October 28-30, 1988.

HBES. (1990). Summary of the first Human Behavior and Evolution Conference: Evanston, Illinois, August, 1989, Human Behavior and Evolution Society Newsletter, 1(1), 2-4, July 1990.

Lévi-Strauss, C. (1985). Claude Lévi-Strauss à l’université Laval, Québec (septembre 1979), prepared by Yvan Simonis, Documents de recherche no. 4, Laboratoire de recherches anthropologiques, Département d’anthropologie, Faculté des Sciences sociales, Université Laval.

Stone, L. and P.F. Lurquin. (2005). A Genetic and Cultural Odyssey. The Life and Work of L. Luca Cavalli-Sforza. New York: Columbia University Press.

Symons, D. (1989). A critique of Darwinian anthropology, Ethology and Sociobiology, 10, 131-144.

Tooby, J. and L. Cosmides. (1989). Evolutionary psychology and the generation of culture, Part I. Theoretical considerations, Ethology and Sociobiology, 10, 29-49.

van den Berghe, P. L. & P. Frost. (1986). Skin color preference, sexual dimorphism, and sexual selection: A case of gene-culture co-evolution? Ethnic and Racial Studies, 9, 87-113.

Can evolutionary psychology evolve?

2011-08-20T11:28:00.005-05:00

The Environment of Evolutionary Adaptedness, over a million years ago in the Pleistocene. A founding myth of evolutionary psychology.

In the future, how will we look at evolution and human behavior? Perhaps we’ll still be looking through the lens of evolutionary psychology, albeit a more “evolved” one than the current variety. Or perhaps there will be a new paradigm.

One thing is sure. Evolutionary psychology, as now defined, is untenable. It suffers from several flawed assumptions:

- Human nature is uniform, except for gender differences. It came into existence over a million years ago during the Pleistocene, in the Environment of Evolutionary Adaptedness (EEA). This was long before modern humans began to spread out of Africa some 40,000 years ago and eventually form the populations we know today.

- Given the complexity of human behavior, its genetic basis could not have changed to any appreciable extent since the Pleistocene.

- All present-day humans are therefore essentially the same. All differences in behavior, personality, and temperament must result from a single human nature responding to different environmental inputs.

These assumptions are false. Human genetic evolution has actually accelerated over the past 40,000 years, and even more so over the past 10,000. The latter period, in particular, was not one of people adapting to new physical environments defined by climate, landscape, and vegetation. People were adapting to new cultural environments defined by social structure, normative behavior, and technology.

Yes, human behavior is complex, and any genetic influences must be correspondingly complex. But these influences can be radically changed by a few point mutations. There’s no need to start from scratch, as John Tooby and Leda Cosmides imply. There may simply be changes to developmental timing, such as an infant’s mental plasticity being extended into older life stages. Or there may be changes to the degree of masculinization or feminization. The possibilities are endless. Again, there is no need to posit a huge number of genetic changes.

Yes, we are adapted to past environments—and not to the present one. And there is often a mismatch between something that made sense in the past and our present reality. But why assume a time gap of over one million years? Is it because the Pleistocene makes an ideal setting for just-so stories?

I suspect there is another, more cynical reason. By placing the evolutionary origins of human nature in the distant past, one avoids the messy reality of differences among current human populations—differences in outlook, personality, time orientation, and behavioral predisposition. The Pleistocene EEA may be a just-so story about the past, but it has also had a real impact on the present. It was part of the deal that made evolutionary psychology possible, in the wake of the firestorm that consumed sociobiology.

Will evolutionary psychology evolve?

A paradigm can evolve. Medicine was a pseudo-science that killed more patients than it cured as late as the 1920s. In the space of a few decades, the situation completely reversed. There have been similar turnarounds in other fields. Alchemy became chemistry, and astrology became astronomy.

Indeed, there have been calls for a rethinking of evolutionary psychology, even from Tooby and Cosmides. “Although the hominid line is thought to have originated on edges of the African savannahs, the EEA is not a particular place or time” (Tooby and Cosmides, 2005, p. 22). It is a composite of whichever selection pressures brought each adaptation into existence. There are thus potentially as many EEAs as there are adaptations, and some may be later than others.

This year, several evolutionary psychologists authored what may be called a manifesto for change:

We argue that the key tenets of the established EP paradigm require modification in the light of recent findings from a number of disciplines, including human genetics, evolutionary biology, cognitive neuroscience, developmental psychology, and paleoecology. For instance, many human genes have been subject to recent selective sweeps; humans play an active, constructive role in co-directing their own development and evolution; and experimental evidence often favours a general process, rather than a modular account, of cognition. (Bolhuis et al., 2011)

The text parallels my recent paper in Futures, sometimes strikingly so. It starts off by observing that in the early years of evolutionary psychology “our knowledge of the human genome was limited and gradualism dominated evolutionary thinking.” Today, we know differently:

Events in the Holocene (the last 10,000 years), particularly the adoption of agriculture, domestication of animals, and the increases in human densities that these practices afforded, were a major source of selection on our species, and possibly accelerated human evolution. Evidence from the human genome strongly suggests that recent human evolution has been affected by responses to features of the environment that were constructed by humans, from culturally facilitated changes in diet, to aspects of modern living that inadvertently promoted the spread of
diseases. (Bolhuis et al., 2011)

This recent evolution has especially shaped the human brain: “Genes expressed in the human brain are well-represented in this recent selection.”

Even when assessed on its own terms, the Pleistocene EEA looks more and more like a myth, and should be treated as such:

[…] the abstract concept of stable selection pressures in the EEA is challenged by recent evidence from paleoecology and paleoanthropology. The Pleistocene was apparently far from stable, not only being variable, but progressively changing in the pattern of variation. The world experienced by members of the genus Homo in the early Pleistocene was very different from that experienced in the late Pleistocene, and even early anatomical modern Homo sapiens that lived around 150,000 years ago led very different lives from Upper Paleolithic people (40,000 years ago) (Bolhuis et al., 2011)

Is a paradigm shift in the offing? Probably. But what form will it take? Perhaps the second question is unimportant. Whether evolutionary psychology changes or disappears, we’ll be looking at evolution and human behavior in a very different light.

To be cont’d

References

Bolhuis, J.J., G.R. Brown, R.C. Richardson, and K.N. Laland. (2011). Darwin in mind: New opportunities for evolutionary psychology, PLoS Biol 9(7): e1001109. doi:10.1371/journal.pbio.1001109
http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001109

Frost, P. (2011). Human nature or human natures? Futures, 43, 740–748.
http://dx.doi.org/10.1016/j.futures.2011.05.017

Tooby, J. and L. Cosmides. (2005). Conceptual foundations of evolutionary psychology, in: D. M. Buss (Ed.) The Handbook of Evolutionary Psychology, Hoboken, NJ: Wiley, pp. 5-67.

Evolution and human behavior: Towards a new paradigm?

2011-08-13T09:42:00.008-05:00

Illustration from Darwin’s book The Expression of the Emotions in Man and Animals (1872)

Evolution has shaped not only our anatomy but also our behavior. This was recognized by Charles Darwin himself in his work The Expression of the Emotions in Man and Animals (1872). Not until the early 20th century, however, would evolution and human behavior emerge as a real field of study. It has gone by three successive names so far:

Ethology

This largely German school began in 1937 with the founding of the journal Zeitschrift für Tierpsychologie, mainly through the efforts of Konrad Lorenz. The initial aim was to understand the evolutionary origins of human behavior by identifying human behavioral patterns, by examining how they develop during the life of an individual, and by comparing them to homologous behaviors in other primates and mammals.

From the 1960s onward, ethology increasingly shunned the study of human behavior, ostensibly because only nonhuman species could be observed under controlled conditions. Once we had fully understood how and why they behave, it would then be possible to move on to humans. This self-imposed limitation became self-reinforcing: only zoologists went into this field of study, and the occasional musings about human behavior tended to be amateurish.

When did ethology cease to mobilize research into human behavior? The cut-off date probably lies shortly after Lorenz’s death in 1989 and the publication of Human Ethology by his student Eibl-Eibesfeldt the same year.

Sociobiology

Launched in the late 1970s, this North American school drew heavily on the latest developments in evolutionary thinking, which in turn drew on economics and game theory. From the outset, it ran into a firestorm of opposition that doomed any real chances for growth or even survival.

Even under better circumstances, it is doubtful whether this field of study could have survived without serious rethinking. Its main shortcomings were:

- “presentism,” a tendency to see contemporary human behavior as an adaptation to present environments, however recent or novel they might be.

- a resulting tendency to see modern behavior as being necessarily adaptive, despite evidence to the contrary. Falling birth rates, for instance, were attributed to parents switching to a K-type reproductive strategy.

- a disinterest in the actual pathways by which genes influence behavior. Such influences were said to be unknowable. Instead, sociobiologists preferred to invoke a mysterious “fitness-maximizing mechanism.”

- naïve and often impressionistic use of anthropological data

By the 1990s, few sociobiologists wished to identify themselves as such, if only because the term itself had become an obstacle to public acceptance. In 1997, this field did away with itself. Its leading journal, Ethology and Sociobiology, was renamed Evolution and Human Behavior.

Evolutionary psychology

This school is likewise North American and largely based in California, its leading pioneers being Leda Cosmides, John Tooby, Don Symons, and David Buss. It took over from sociobiology in the mid-1990s and still dominates thinking on the evolutionary origins of human behavior. Its writers come overwhelmingly from psychology and to a lesser extent from anthropology, biology, and even the humanities. Psychologists are over-represented largely because their discipline better weathered the anti-sociobiology firestorm of the 1980s.

In reaction to sociobiology, evolutionary psychology sought to understand the actual ways in which genes influence behavior, which was now seen as an adaptation to past environments. This school developed around four basic principles:

1. The environment of evolutionary adaptedness (EEA). Past environments have shaped human nature. How far back in the past is not clearly stated, although the EEA has typically been equated with the savanna of Pleistocene Africa.

2. Gradualism. The human mind is a product of co-adapted gene complexes that cannot respond quickly to selection. Like the EEA, gradualism denies that human nature could have evolved differently in the different cultural and physical environments that modern humans entered as they spread out of Africa over the past 40,000 years

3. Modularity of the human mind. Because specific adaptive problems require specific adaptive solution, the human mind is mainly composed of domain-specific, modular programs.

4. Universal human nature. There is only one human nature. Apparent differences in human nature are simply different outcomes of species-wide programs (as a result of different environmental inputs).

The above principles are more than a reaction against sociobiology. They’re an overreaction. Some genetic determinants of human behavior are clearly post-Pleistocene in origin. How are we supposed to explain them? And what about more domain-general aspects of the human mind, like general intelligence?

But, then, this “overreaction” isn’t just a matter of rational argument. There is also fear. Leda Cosmides and John Tooby remember the firestorm that ravaged sociobiology in the 1980s. They then wandered a long time in the wilderness before finally landing a permanent academic position. Time and again, they had to convince potential employers or funding agencies that they had no secret interest in psychological differences among human populations.

And so was paved the road to evolutionary psychology, a road paved with the best of intentions: legitimate criticisms of sociobiology, with an understandable desire to lead a normal academic life.

This desire is described by Cosmides and Tooby in one of their articles:

The Standard Model therefore frees those in the biological sciences to pursue their research in peace, without having to fear that they might accidentally stumble into or run afoul of highly charged social or political issues. It offers them safe conduct across the politicized minefield of modern academic life. This division of labor is, therefore, popular: Natural scientists deal with the nonhuman world and the “physical” side of human life, while social scientists are the custodians of human minds, human behavior, and, indeed, the entire human mental, moral, political, social, and cultural world. (Barkow, Cosmides, & Tooby, 1992)

Ironically, in seeking to challenge this modus vivendi, Cosmides and Tooby have ended up creating a new one. We can now study human behavior from an evolutionary perspective, but only if we exclude (1) psychological differences between human populations and (2) domain-general aspects of human behavior, e.g., general intelligence. That’s the implicit deal behind evolutionary psychology—an acquiescence to self-censorship.

How has the deal worked out? Quite well, apparently. Evolutionary psychology has attained a degree of respectability that seemed impossible back in the mid-1990s. In 1995, only 261 newly published academic books or articles mentioned the term “evolutionary psychology.” Last year, the figure was 3,570 (see Google Scholar). This field now has its own handsomely illustrated textbooks, grad school programs, and research centers. Perhaps more importantly, it now incurs few costs to a career in academia.

But maybe this would have happened anyway. By the mid-1990s, the anti-sociobiology firestorm was burning itself out. The far left had entered a steep decline, and its graying leadership was pushing sixty. With rising tuition, a weakening economy, and aging demographics, the social sciences were attracting fewer and better students. Meanwhile, the advent of the Internet was “deregulating” the marketplace of ideas.

Has self-censorship calmed debate over evolution and human behavior? I’m not so sure. In any case, it has certainly done much to distort the way the debate is framed. And this is the sad part. Evolutionary psychologists often produce interesting findings, only to fall down when they try to interpret them.

For instance, it is known that children develop differently if the biological father is absent and a strange male is present (e.g., a stepfather). In both sexes, sexual activity will begin earlier with less stable pair bonds. Sons will show hypermasculine behavior, such as aggressive acting out, boasting, and risk-taking. Daughters will reach puberty earlier and judge potential mates by current appearance and status in the male hierarchy rather than by steadfastness and ability to support a family. It has thus been hypothesized that an early sensitive period allows certain environmental cues, like father presence, to define reproductive strategy later in life (Ellis et al., 2003).

The above reasoning is consistent with the four principles of evolutionary psychology. It’s also false. A recent twin study has found that early menarche is predicted as strongly by a step-uncle’s presence as by a stepfather’s. “It does not seem necessary for a child to experience the direct environmental influence of a stepfather to exhibit an accelerated age of menarche—as long as she is genetically related to someone who does have a stepfather” (Mendle et al., 2006).

In other words, a woman may be more prone than others to early menarche, a high degree of female reproductive autonomy, and low expectations of paternal investment. It’s not as if she acquires this reproductive strategy from her childhood environment. Instead, she inherits it genetically from her mother and absent father.

So where do we go from here? We can continue down the road paved by Cosmides and Tooby. But it will often take us to a dead end. We’ll then have to waive some or all of the above four principles, assuming of course we wish to understand human behavior.

To be cont’d

References

Barkow, J.H., Cosmides, L., & Tooby, J. (eds.) (1992). The Adapted Mind. Evolutionary Psychology and the Generation of Culture, New York, Oxford: Oxford University Press.

Ellis, B.J., J.E. Bates, K.A. Dodge, D.M. Fergusson, L.J. Horwood, G.S. Pettit, L. Woodward. (2003). Does father absence place daughters at special risk for early sexual activity and teenage pregnancy? Child Development, 74, 801-821.

Mendle, J., E. Turkheimer, B.M. D’Onofrio, S.K. Lynch, R.E. Emery, W.S. Slutske, and N.G. Martin. (2006). Family structure and age at menarche: a children-of-twins approach, Developmental Psychology, 42, 533-542.

Brain size, latitude, and ambient light

2011-08-06T08:31:00.001-05:00

An Inuk wearing snow goggles. Is ambient light at its lowest in Inuit territory?

The logjam seems to have broken. On the heels of Lewis et al. (2011), we now have another paper on variation in brain size among human populations, this time by Pearce and Dunbar (2011).

Brains vary in size by latitude, being bigger at higher latitudes and smaller at lower ones. This variation seems to reflect an adaptation to climate. But just how, exactly, does climate relate to brain size? How direct or indirect is the relationship?

Pearce and Dunbar (2011) argue that bigger brains are an adaptation to lower levels of ambient light. Specifically, dimmer light requires larger eyes, which in turn require larger visual cortices in the brain. Using 73 adult crania from populations located at different latitudes, the two authors found that both eyeball size and brain size correlate positively with latitude. The correlation was stronger with eyeball size, an indication that this factor was driving the increase in brain size.

How credible is this explanation? First of all, visual cortex size was not directly measured. The authors inferred that this brain area was responsible for the increase in total cranial capacity. Obviously, they couldn’t have done otherwise. They were measuring skulls, not intact brains.

But there’s another problem—one in the realm of logic. A lot of things correlate with latitude: pigmentation, mating systems, rules of descent, degree of paternal investment, and so on. If one of them correlates more strongly with latitude than the others, does it therefore cause the others? Not at all. It may be closer than the others to this shared cause, but it doesn’t necessarily lie on the same causal chain as the others.

In other words, the level of ambient light does not produce a single cascade of consequences, with eyeball size being the first consequence. There are probably many different cascades.

To date, the best map of human variation in brain size is the one by Beals et al. (1984) (see previous post). If dimness of light is the main determinant, brain size should be highest in northwestern Europe, northern British Columbia, the Alaskan panhandle, and western Greenland. These regions combine high latitudes with generally overcast skies. Yet they are not the regions where humans have the biggest brains. Instead, brain size is at its highest among humans from the northern fringe of Arctic Asia and from northeastern Arctic Canada. These regions are, if anything, less overcast than average. They often have high levels of ambient light because of reflection from snow and ice.

The jury is still out on this question. I suspect, however, that the following three factors probably explain variation in brain size with latitude.

1. Among hunter-gatherers, hunting distance increases with latitude because there are fewer game animals per square kilometer (Hoffecker, 2002, pp. 8-9). Hunters must therefore store larger amounts of spatiotemporal information (landmarks, previous hunting itineraries, mental simulations of possible movements by game animals over space and time). This factor might explain why brains have grown smaller since the advent of agriculture.

2. The seasonal cycle matters more at higher latitudes. As a result, northern hunter-gatherers, and northern agriculturalists even more so, must plan ahead for the next season (or even for the season after the next one).

3. Women gather less food at higher latitudes and almost none in the Arctic. They are thus free to specialize in other tasks, such as garment making, food processing, and shelter building. This “family workshop” creates opportunities for greater technological complexity, which in turn increases selection for greater cognitive performance.

I suspect bigger brains provide not so much greater intelligence as greater ability to store information. As such, they nonetheless pre-adapted northern hunter-gatherers for later advances in cultural evolution.

References

Beals, K.L., C.L. Smith, and S.M. Dodd (1984). Brain size, cranial morphology, climate, and time machines, Current Anthropology, 25, 301–330.

Hoffecker, J.F. (2002). Desolate Landscapes. Ice-Age Settlement in Eastern Europe. New Brunswick: Rutgers University Press.

Lewis, J.E., D. DeGusta, M.R. Meyer, J.M. Monge, A.E. Mann, R.L. Holloway. (2011). The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias, PLoS Biology, 9(6) e1001071

Pearce, E. and R. Dunbar. (2011). Latitudinal variation in light levels drives human visual system size, Biology Letters, doi: 10.1098/rsbl.2011.0570

Rapid cultural evolution: the case of the Iroquois

2011-07-30T09:47:00.006-05:00

Cahokia, an Amerindian town on the Mississippi of 10,000 to 20,000 people. A forerunner of what might have been?

Native Indian societies are widely seen as unchanging before Europeans came into the picture. This view sometimes has almost religious overtones. Amerindians lived in harmony with their world, and this harmony was broken by the White man.

Yet this view is at odds with a growing consensus among archeologists. Rapid cultural evolution was already under way in eastern and central North America when the first Europeans arrived. Had their arrival been postponed long enough, they would have encountered millions of sedentary Indians in a zone stretching from the lower Mississippi to southern Ontario. A northern Aztec Empire.

The northern end of this zone experienced the most rapid change. Nomadic hunter-gatherers roamed over southern Ontario and New York State until late in prehistory. Then, some time after 500 AD, these Iroquoian-speaking peoples began to settle into villages and cultivate corn, beans, and squash.

After a slow start, this cultural evolution began to accelerate circa 1300 AD. The result, according to anthropologist Bruce Trigger, was “a dramatic revolution in Iroquoian life”:

[…] Houses became longer and were inhabited by many more families. The length of the houses varied greatly. They were located closer together and began to be aligned parallel to one another in groups that may have been occupied by related matrilineages or individual clans. Villages were surrounded by more elaborate fortifications, and at least some of the village planning may have been intended to reduce the amount of palisades that had to be constructed and manned in order to defend a settlement (Noble 1969:19). Higher frequencies of house extensions and of interior house post densities suggest that individual houses were being occupied for longer periods than previously. This would also have encouraged sturdier construction. (Trigger, 1985, p. 92)

These changes in material culture went hand in hand with an increase in social complexity:

In New York State cultural groupings ancestral to the historical tribes of that region - including the Five Nations Iroquois - also become more clearly defined. […] In all these areas many communities continued to increase in size, probably mainly as a result of the union of two or more existing ones. Many settlements had 1,500 inhabitants. While houses became shorter, they still differed considerably in size. Village planning became more elaborate, with open spaces being provided as work areas and for the disposal of garbage. (Trigger, 1985, p.100)

The increase in social complexity brought changes in political organization:

[…] There is also widespread evidence at this time of neighbouring and hitherto autonomous settlements clustering close to one another to form "tribes." The best documented example is Tuck's (1971:214-16) demonstration that two villages, one small and the other much larger, settled within a few kilometres of each other between AD 1450 and 1475 to found the Onondaga nation. The larger village was itself the result of an earlier fusion of two small ones. This drawing together of communities to form larger settlements and tribes led to the abandonment of many formerly settled areas and produced more widely separated clusters of human habitation. It also created new political groupings, each of which embraced more people than any previous ones in this part of North America had. (Trigger, 1985, p. 102)

There were also ideological innovations that may have come from places farther south, such as the ritual killing of prisoners of war:

Certain key elements, including the use of prisoners, the removal of the heart, the killing of the victim on an elevated platform and in view of the sun, and finally the cooking and eating of all or parts of his body, connect this northern Iroquoian ritual with ones practised in the southeastern United States and in Mexico by the Aztecs, although many specific differences remain. (Trigger, 1985, p. 97)

Finally, there was an intensification of warfare that began before the arrival of European traders or settlers:

There is now also much archaeological evidence of warfare after AD 1400 between Iroquoian groups in the London area and the Fort Meigs culture, found in extreme southwestern Ontario and around the western end of Lake Erie. […] Hence the warfare between the Neutrals and the Central Algonkians which continued into the 1640s might have been the final stages of a conflict that had begun in the prehistoric period. (Trigger, 1985, p. 107)

Trigger concludes that these processes of State formation and militarization were endogenous:

[…] archaeologists may have oversimplified the late prehistory of the Iroquoian peoples and underestimated the dynamism of their cultural pattern and its capacity to generate new forms of creative and destructive behaviour. The Iroquoians now seem to have evolved the essential features of their way of life before the first Europeans appeared along the east coast of Canada. (Trigger, 1985, p. 108)

This cultural evolution was actually accelerating when the Europeans arrived. What if their arrival had been postponed? The Iroquois would have certainly surpassed the mound builders of the Mississippi valley and probably reached a level of civilization like that of the Aztecs.

Such a scenario almost did happen. Indeed, conditions were far from ideal when the English and the French began to settle North America. Western Europe was just returning to the population levels that had existed before the Black Death. The North Atlantic was entering a cold period, called “The Little Ice Age,” that made trans-oceanic crossings difficult. Finally, the Turks were pushing deep into Central Europe, laying siege to Vienna in 1529 and 1683 and vowing to drive on to Cologne.

Had this fragile context taken a turn for the worse, there might have been insufficient will or ability to colonize the Americas. European settlers would have perhaps arrived on the Eastern Seaboard only in the late 1700s.

And beyond the Appalachians, they would have found millions of sedentary Amerindians living in fortified cities and recently united under the aegis of the Iroquois Confederacy …

Reference

Trigger, B.G. (1986). Natives and Newcomers: Canada's "Heroic Age" Reconsidered, Montreal: McGill-Queen's University Press.

Continent orientation, cultural evolution, and the Amerindian exception

2011-07-23T09:23:00.003-05:00

Pre-Columbian copper artifacts from Illinois, Oklahoma, Missouri, and Illinois.

In my last post, I criticized Jared Diamond’s theory about continent orientation and cultural evolution. This theory posits that people, and hence ideas, are likelier to circulate along an east-west axis than along a north-south one. This is because people tend to move about in environments that have similar climates and ecosystems. Eurasia has thus reaped the benefits of having a belt of societies—stretching from Spain to Japan—that can borrow new ideas from each other with relative ease.

This is not the case with sub-Saharan Africa, which is oriented north-south. It has a much more limited pool of ideas to draw upon. Diamond argues that this is one big reason why sub-Saharan Africans failed to develop beyond the stage of simple agricultural societies.

But what about the Americas? Aren’t they even more north-south oriented? How, then, did advanced civilizations develop in Mesoamerica and the Andes? And why did they develop even faster than ancient civilizations in Eurasia?

These were the questions I raised in my last post. Here, I’ll argue that this fast pace of cultural evolution was not limited to Mesoamerica and the Andes.

Take the transition from hunting and gathering to agriculture. Around 100 BC, agriculture was still confined to the American southwest. The rest of the present-day United States was home to nomadic hunter-gatherers. By 800 AD, agriculture had spread throughout most of the central and eastern U.S. and into southern Ontario. By 1000, the Mississippi valley had urban centers that were each built around a central plaza with earthen temple mounds. These developments were accompanied by a suite of cultural innovations: skilled metalworking; food storage in pits and cribs; timber palisades and bastions; and formation of intertribal confederacies.

This pace of change was, if anything, faster than comparable change elsewhere in the world. There is little evidence that the availability of new ideas was a significant brake on cultural evolution in the Americas—at least no more so than in Eurasia, where new ideas were supposedly more available. Agriculture, for instance, took more than five thousand years to spread from the Middle East to northern Europe.

Indeed, there is evidence of ancestral Amerindians having access to useful ideas that they nonetheless chose not to use. The wheel, for instance, was known to the Aztecs, who used it for toys. But they never used it for anything else.

Another example is copper working. This metal had been worked in eastern North America since at least 5,000 BC, and the resulting artifacts were “far larger and better shaped than any known native copper objects from the Middle East” (Smith, 1968, p. 242). Yet there was never any melting, smelting, casting, or alloying of copper. In particular, there was no attempt to harden copper by combining it with tin, lead, antimony, or arsenic, although such elements were available in the Americas. Such possibilities were there for the taking, but there was apparently little interest in doing so.

As Ehrhardt (2009) comments, “It is provocative and useful to think about why North American metal working technology did not follow the same developmental paths documented for other New World metal working industries.”

One factor may have been the overwhelming use of copper for status or ritual purposes, i.e., ornamentation that did not require hard metals (Ehrhardt, 2009). While such purposes certainly prevailed in Old World civilizations, the latter also used metalworking to make functional objects like kitchenware and tableware. Perhaps New World civilizations suffered not from a lack of ideas but rather from limits on the use of ideas. Mental innovation was subordinated to the interests of the ruling caste. The needs of ordinary folk came a distant second.

Thus, the availability of new ideas is not the main brake on cultural evolution. What matters more is the perceived usefulness of those ideas, and the people who decide which ones are useful and which are not.

Further thoughts

Why did cultural evolution follow a more fruitful path in the Americas than in sub-Saharan Africa? The latter had more opportunities for east-west exchange, being next to Eurasia and its cultural innovations. According to Diamond’s theory, cultural evolution should have been faster in sub-Saharan Africa than in the Americas. Yet the reverse happened.

How come? The main reason was that Amerindian men and women had to plan over a predictable yearly cycle. The men also had to provide for their mates and children, especially in winter—an obligation that not only integrated father, mother, and children into a single unit of family production but also freed the mother to specialize in other tasks, like garment making, food processing, and home building.

These factors pre-adapted Amerindians for later cultural evolution. The “family workshop” of nomadic hunter-gatherers became a model for the economic and political structures of sedentary farmers.

References

Diamond, J. (1997). Guns, Germs and Steel: The Fates of Human Societies, New York: W.W. Norton.

Ehrhardt, K.L. (2009). Copper Working Technologies, Contexts of Use, and Social Complexity in the Eastern Woodlands of Native North America, Journal of World Prehistory, 22, 213-235.

Smith, C. S. (1968). Metallographic study of early artifacts made from native copper (pp. 237–252). Warsaw: Actes du XIe Congrès International d’Histoire des Sciences VI.

Big Other?

2011-07-16T12:43:00.001-05:00

Julos Beaucarne, March 2007

Your Christ is Jewish
Your car is Japanese
Your couscous is Algerian
Your democracy is Greek
Your coffee is Brazilian
Your chianti is Italian

And you reproach your neighbor for being a foreigner

The above poem, by Belgian singer Julos Beaucarne, has been making the rounds of late-night radio and Facebook pages for the past few years. Its message? Without the contributions of other cultures, we’d be less advanced, less refined, and less well off. In short, we’d be nobodies. We have met the Others, and they are us.

This is Big Other at its finest. If poetry leaves you cold, a more intellectual version is available in the pages of Guns, Germs and Steel: The Fates of Human Societies by Jared Diamond.

Diamond starts off by noting that people, and hence ideas, are more likely to circulate between regions that are ecologically and climatically similar. Hence, the circulation of ideas tends to be much more east-west than north-south.

If we look at a world map, we see that Eurasia is oriented east-west and Africa north-south. Eurasians have thus benefited from a greater number of cultural innovations because they can tap into a belt of human creativity stretching from Gibraltar to Tokyo. Africans, by contrast, have not had this advantage. This, argues Diamond, is one big reason why Africa fell behind Eurasia in the race for global dominance.

Absent from this argument is any mention of the Americas. Those continents likewise follow a north-south axis, even more so than Africa. Yet they became home to advanced civilizations in Mesoamerica and the Andes. There is some evidence that the Incas had cultural contacts with Polynesian seafarers. Other than that, both of these civilizations had to develop on their own.

Did they develop more slowly than Eurasian civilizations? Apparently not. Mesoamerican civilizations reached milestones in cultural development at a faster rate than did civilizations in the Middle East. The Zapotecs developed calendar and writing systems barely 1,000 years after their first permanent farming villages. In the Middle East, the time span was over 5,000 years.

Jared Diamond, like Julos Beaucarne, is begging the question. Yes, as Eurasian cultures came more into contact with each other, they each had fewer innovations of local origin and more of foreign origin. But would these cultures have been worse off if forced to innovate on their own?

Indeed, an argument can be made that exposure to the “Other” tends to stifle local creativity. During the thirty years after the Second World War, Americans lived under a regime of semi-autarky, producing most of their own goods, educating most of their own talent, and generating most of their own inventions. This was nonetheless a period of almost frenetic cultural and economic innovation. Is the United States more innovative today, now that it’s much more open to the rest of the world?

It is even doubtful whether the east-west flow of ideas explains the rise of the European world to global dominance between 1500 and 1900—the main theme of Diamond’s book. This rise to dominance was fueled by a technological revolution that occurred largely in northwestern Europe, with the exception of only two major innovations of non-European origin: gunpowder and the printing press.

Before 1500, Europeans did borrow considerably from the Middle East in such fields as chemistry, mathematics, and engineering, but this was a time of slow economic growth and geopolitical weakness. Europe took off economically and geopolitically only when it developed its own intellectual resources.

Reference

Diamond, J. (1997). Guns, Germs and Steel: The Fates of Human Societies, New York: W.W. Norton.

Brain size and latitude: Why the correlation?

2011-07-09T08:48:00.007-05:00

Human variation in cranial capacity. Black, 1,450 cc and over; checkerboard, 1,400-49 cc; crosshatching, 1,350-99 cc; horizontal striping, 1,300-49 cc; diagonal striping, 1,250-99 cc; dots, 1,200-49 cc; white areas, under 1,200 cc (Beals et al., 1984)

So Stephen Jay Gould was wrong, and Samuel George Morton was right. Brain size does vary among human populations. But what does this variation mean? Why does it exist?

This question is briefly addressed by Lewis et al. (2011):

[…] cranial capacity variation in human populations appears to be largely a function of climate, so, for example, the full range of average capacities is seen in Native American groups, as they historically occupied the full range of latitudes

For more information, the reader is referred to an earlier study: Beals, Smith, and Dodd (1984). The latter plotted cranial capacity from 122 human populations. The resulting map is shown above. A few caveats: there is a LOT of interpolation and extrapolation in the above map. There are no data points from Cambodia or southern Vietnam, and hence nothing to justify the very low values assigned to that region. Southern India is assigned a very low cranial capacity on the basis of a small sample that includes Veddas—a relic group of hunter-gatherers from Sri Lanka.

All in all, and keeping these caveats in mind, cranial capacity does seem to correlate with latitude. Why? According to the authors, heads are larger at higher latitudes to reduce heat loss. An object will lose less heat if its ratio of volume to surface area is high. There has thus been natural selection to make heads broader and more globular at higher latitudes. The increase in brain size is incidental.

This explanation was challenged in the comments section following the Beals, Smith, and Dodd (1984) article. A Japanese commenter, Iwatoro Morimoto, pointed out that "in recent centuries, brachycranic skulls show a considerable increase in frequency in Eurasian populations, including the Japanese." Since mean temperatures have changed little in recent centuries, there must have been another factor at work. Unfortunately, Morimoto provided no references to back up this counter-argument.

Another commenter, Erik Trinkaus, similarly pointed out that Neanderthal cranial capacity was no bigger during glacial periods than during interglacials. The same was true for early modern humans. For populations already established at northern latitudes, cranial capacity shows no evidence of rising and falling with mean temperature.

A recent analysis has nonetheless found a significant correlation between cranial capacity and latitude among ancestral hominids in general, ranging from A. Afarensis to H. sapiens (Henneberg and Miguel, 2004). The correlation remained even when the authors controlled for each skull’s time period and, thus, was not due to the overall rise in cranial capacity over time and the parallel expansion of ancestral hominids into higher latitudes.

In sum, cranial capacity does correlate with latitude. It is less clear, however, whether this correlation is mediated by mean temperature and the need to reduce heat loss.

Higher cognitive demands at higher latitudes?

Could it be that cognitive demands increased as ancestral humans entered higher latitudes? Not because mean temperatures were lower but because the yearly cycle presented a greater diversity of environments and required much more foresight. Between ‘summer’ and ‘winter,’ the differences are much greater in the temperate and arctic zones than in the tropics.

This point is elaborated upon by Hoffecker (2002, p. 135). Among early modern humans, tools and weapons were more complex at arctic latitudes than at tropical latitudes. “Technological complexity in colder environments seems to reflect the need for greater foraging efficiency in settings where many resources are available only for limited periods of time.” Arctic humans coped with resource fluctuations and high mobility requirements by planning ahead and by developing untended devices (e.g., traps and snares) and means of food storage.

In addition, these increased cognitive demands fell on both men and women. Paternal and maternal investment were much more equal than in the tropics, where women provided for their families year-round with less male assistance (Kelly, 1995, pp. 268-269; Martin, 1974, pp. 16-18). Indeed, because men were the main food providers beyond the tropical zone, women could care for their families by developing a new range of tasks: food processing (e.g., butchery and carcass transport); shelter building; garment making; leather working; transport of material goods; etc. (Waguespack, 2005). This technological revolution would ultimately lead to what we now call ‘civilization’ (Frost, 2008).

Further thoughts

Curiously, Beals, Smith, and Dodd (1984) cite Gould’s 1978 Science article—the one claiming that Morton had unconsciously fudged his data to make brains look bigger among Europeans than among sub-Saharan Africans. Yet these authors declined to mention the inconsistencies between Gould’s findings and their own. Their reference to Gould is studiously neutral: “Critiques of the use of brain size in typology have been offered by Gould.”

There has not been much comment on the Beals, Smith, and Dodd (1984) article. The most substantive one seems to be a blog post by Robert Lindsay (2010) who calls their map a “train wreck” for claims that cranial capacity correlates with IQ:

White racists like to make a big deal about the supposed correlation between head size and intelligence and race. A nice little chart showing the basically dishonest portrayal they attempt based on cherry-picking data is below.

Methinks that Lindsay takes the fine details on that map a bit too seriously. Many of the details are simply creative extrapolation and infilling; otherwise, the map roughly corresponds with world distribution of mean IQ. Furthermore, no one is claiming that cranial capacity is the only determinant of IQ. There are undoubtedly many others: cortical surface area, myelinization of nerve fibers, relative importance of domain-general thinking, etc.

But he does make a good point about the Amerindian data.

As you can see, in the Americas, there is no good evidence whatsoever for head size and IQ. I am not aware that Amerindian IQ varies in the Americas. The average is apparently 87 across the continent. If anyone can show me that it varies by latitude, please do.

Agreed. No one can, for now. But a hypothesis is not false because no one has bothered to test it.

References

Beals, K.L., C.L. Smith, and S.M. Dodd (1984). Brain size, cranial morphology, climate, and time machines, Current Anthropology, 25, 301–330.

Frost, P. (2008). The path to civilization? Evo and Proud, March 10, 2008.
http://evoandproud.blogspot.com/2008/03/path-to-civilization.html

Henneberg, M. and C. de Miguel. (2004). Hominins are a single lineage: brain and body size variability does not reflect postulated taxonomic diversity of hominins, Journal of Comparative Human Biology, 55, 21–37

Hoffecker, J.F. (2002). Desolate Landscapes. Ice-Age Settlement in Eastern Europe. New Brunswick: Rutgers University Press.

Kelly, R.L. (1955). The Foraging Spectrum. Diversity in Hunter-Gatherer Lifeways. Washington: Smithsonian Institution Press.

Lewis, J.E., D. DeGusta, M.R. Meyer, J.M. Monge, A.E. Mann, R.L. Holloway. (2011). The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias, PLoS Biology, 9(6) e1001071

Lindsay, R. (2010). The Head Size/IQ/Race Trainwreck, March 11
http://robertlindsay.wordpress.com/2010/03/11/the-head-sizeraceiq-trainwreck/

Martin, M.K. (1974). The Foraging Adaptation — Uniformity or Diversity? Addison‑Wesley Module in Anthropology 56.

Waguespack, N.M. (2005). The organization of male and female labor in foraging societies: Implications for early Paleoindian archaeology. American Anthropologist, 107, 666-676.

Arroseur arrosé?

2011-07-02T13:16:00.005-05:00

Stephen Jay Gould in a 1997 Simpsons episode (Pagepulp). Gould enjoys an almost iconic status in American culture.

Who was the greatest evolutionary scientist of recent times? Most people would answer “Stephen J. Gould,” at least on this side of the Atlantic. With the possible exception of L.L. Cavalli-Sforza, he was the one best known to non-biologists, partly because he wrote well but also because he said the sorts of things that people in the humanities and social sciences wished to hear. My anthropology department was no exception. When I presented my dissertation proposal, one committee member launched into a criticism that he supported with a quote from one of Gould’s works. I didn’t understand the relevance of the quote—other than the banal point that many scholars are unconscious liars. But it hit home among the other people present.

And why not? When Gould died, in 2002, his reputation was unshakable. You might have disagreed with his conclusions, but his methodology seemed sound. This was particularly so with his 1978 Science paper on 19th-century physical anthropologist Samuel George Morton, which showed how a reputedly objective scientist had unconsciously fudged his data to make Europeans look larger-brained than sub-Saharan Africans.

These findings were later carried over into The Mismeasure of Man (1981), a bestseller and now required reading in many undergrad social science courses. Gould also brought up his 1978 paper in public lectures, making it a centerpiece of his attacks on the “myth of scientific objectivity.” In reviewing a posthumous Gould anthology, Richard Lewontin, underlined this point as “the one that is most important to the public understanding of science”:

Despite the myth of detached objectivity that scientists propagate, their motivations are as messy as everyone else's. In particular, they have political, social, and personal concerns that may influence what they do, how they do it, and what they say about it. Putting aside deliberate fraud, of which we have an embarrassment of examples, the gathering of data, their statistical representation, and their interpretation offer many opportunities for unconscious bias toward conclusions that we already "knew" to be true. (Lewontin, 2008)

By the time of his death, Gould had become an icon of popular culture:

Dr. Gould achieved a fame unprecedented among modern evolutionary biologists. The closest thing to a household name in the field, he became part of mainstream iconography when he was depicted in cartoon form on "The Simpsons." Renovations of his SoHo loft in Manhattan were featured in a glowing article in Architectural Digest. (Yoon, 2002)

The Simpsons episode aired in 1997 and is worth summarizing:

Lisa Simpson wants to stop a huge mall development from proceeding at "Sabertooth Ravine" because the ravine is a fossil site. As a compromise, the mall developers decide to let Lisa dig for fossils while they continue to build the mall. While digging, Lisa finds an almost human fossil. Almost, but not quite: in place of arms the fossil has wings. "It's an angel" declare the naive and religiously motivated townfolk. Lisa, who plays the scientific naturalist, will have none of it. She therefore enlists Gould to prove that the fossil is nothing of the sort. Gould claims that the DNA tests he performed proved inconclusive.

[…] In the closing scene, Lisa asks Gould why his test failed to detect that the angel fossil was a fraud. Gould (and mind you, this was Gould's actual voice--he is listed explicitly in the credits) admits that in fact he never did perform the test--even though he claimed he did earlier. (Dembski, 1997)

The Simpsons episode raised a few eyebrows. Was Gould guilty of the sort of shenanigans he had accused others of doing?

Arroseur arrosé

Yes indeed. A team of physical anthropologists recently located half of the skulls that Samuel George Morton had measured more than a century and a half ago. When they remeasured the skulls they found very few errors in Morton’s measurements. More to the point, the errors were distributed randomly. There was, in fact, a non-significant tendency to overestimate African skull size (Lewis et al., 2011).

It is also doubtful whether Morton considered Africans to be less “evolved” than Europeans. His Crania Americana was published in 1839, long before the first attempts to apply evolutionary theory to human races. Morton was in fact a devout Christian who wished to find out whether different human populations were separate species resulting from multiple divine creations or a single species created but once. He had little if any interest in research on human intelligence, which anyhow was embryonic at the time.

Needless to say, Gould never remeasured any of Morton’s skulls. His paper was at best a clumsy re-analysis of Morton’s published data. I say “at best” because Gould bolstered his argument by creating facts out of thin air. It is a wonder that he managed to get published in a first-tier journal like Science, which as a rule publishes only original data.

Further thoughts

There is another disturbing element in this affair. Many of the flaws in Gould’s paper had already been pointed out … twenty-three years ago (Michael, 1988). And they were pointed out in a first-tier journal (Current Anthropology). Yet that other paper was studiously ignored. Gould owed his reputation not so much to the quality of his work as to an academic milieu that covered for him, acting more as cheerleaders than as responsible critics. He was shielded by a personality cult. Without it, he would have been just another biology professor.

What now? Academia will likely enter a long and painful process of “de-Gouldization.” Long, because many other academics were in on the collective lying. Painful, because the lies were far from trivial.

References

Dembski, W.A. (1997). An Analysis of Homer Simpson and Stephen Jay Gould, Access Research Network.

http://www.arn.org/docs/dembski1129.htm

Gould S.J. (1981). The mismeasure of man. New York: W. W. Norton and Company.

Gould , S.J. (1978). Morton’s ranking of races by cranial capacity: unconscious manipulation of data may be a scientific norm, Science, 200, 503–509.

Lewis, J.E., D. DeGusta, M.R. Meyer, J.M. Monge, A.E. Mann, R.L. Holloway. (2011). The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias, PLoS Biology, 9(6) e1001071

Lewontin, R.C. (2008). The Triumph of Stephen Jay Gould, New York Review of Books, 55(2), 39-41, February 14, 2008.

Michael, J.S. (1988). A new look at Morton’s craniological research, Current Anthropology, 29, 349–354.

Pagepulp (2011). The literary world of the Simpsons, April 24
http://www.pagepulp.com/176/the-literary-world-of-the-simpsons/

Yoon, C.K. (2002). Stephen Jay Gould, Biologist and Theorist on Evolution, Dies at 60, New York Times, May 20, 2002,
http://www.nytimes.com/2002/05/20/obituaries/20CND-GOULD.html

Human nature or human natures?

2011-06-25T09:42:00.002-05:00

A new article of mine has just appeared in the journal Futures. All comments are welcome.

Abstract

Most evolutionary psychologists share a belief in one key concept: the environment of evolutionary adaptedness (EEA), i.e., the ancestral environment that shaped the heritable mental and behavioral traits of present-day humans. It is usually placed in the African savannah of the Pleistocene, long before our ancestors began to spread to other continents some fifty thousand years ago. Thus, later environments have not given rise to new traits through genetic evolution.

This belief rests on two arguments: 1) such traits are complex and therefore evolve too slowly to have substantially changed over the past fifty thousand years; 2) because the same time frame has seen our species diversify into many environments, recent traits should tend to be environment-specific and hence population-specific, yet such specificity seems inconsistent with the high genetic overlap among human populations. Both arguments are weaker than they seem. New complex traits can arise over a relatively short time through additions, deletions, or modifications to existing complex traits, and genetic overlap can be considerable even between species that are morphologically, behaviorally, and physiologically distinct.

There is thus no conceptual barrier to the existence of EEAs in post-Pleistocene times. Such a paradigm could shed light on such research topics as the visual word form area, reproductive strategy, predisposition to violence among young men, and personality traits. Eventually, a multi-EEA model may dominate evolutionary psychology, perhaps after an interim period of accommodation with the current model.

Reference

Frost, P. (2011). Human nature or human natures? Futures
http://dx.doi.org/10.1016/j.futures.2011.05.017

More on French Canadians and Tay Sach's

2011-06-18T11:23:00.013-05:00

French Canadian habitants playing at cards (Cornelius Krieghoff). With fewer British merchants than elsewhere, eastern Quebec was a land of opportunity for business-minded French Canadians. Did this selection affect the local gene pool?

When discussion turns to Tay Sach’s, people automatically think of the Jewish community. Yet this inherited illness reaches high levels in other human populations, particularly French Canadians.

Tay Sach’s has three unusual characteristics among French Canadians:

1. It is highly localized geographically, being concentrated in eastern Quebec. In Rimouski, the heterozygote frequency is 7.6%, versus 4.2% among Ashkenazi Jews and 0.3% among French Canadians in Montreal (De Braekeleer et al, 1992).

2. It is caused by two separate mutations: one that arose on the north shore of the St. Lawrence (Charlevoix and Saguenay-Lac Saint-Jean) and another that arose on the south shore (Bas Saint-Laurent) (Zlotogora, 1994).

3. It is relatively recent in origin, being absent in France. Neither mutation can be more than three centuries old and both probably postdate the British conquest of Quebec (1759).

These three characteristics argue for some kind of selective advantage, and not a random founder effect. Among Ashkenazi Jews, the selective advantage seems to be improved mental processing. Indeed, Tay Sach’s is one of four different genetic illnesses that are unusually common among Ashkenazim and that affect the same metabolic pathway in brain tissues (lysosomal storage). Homozygotes suffer neurological degeneration, mental retardation, and other neural problems. Heterozygotes, however, may be better at mentally demanding occupations (Cochran et al., 2006; Frost 2007; Murray, 2007; Zlotogora, 1994).

Interestingly, Tay Sach’s co-occurs in eastern Quebec with another hereditary illness that lies in the same metabolic pathway, i.e., lysosomal storage.

The mucolipidoses are composed of four distinct clinical conditions (designated type I–IV) that result from the accumulation of lipid and carbohydrate molecules due to specific lysosomal enzyme defects. (...) In the absence of this step, lysosomal enzymes are incorrectly routed into the extracellular space. This disorder is rare, with an estimated incidence of 1 in 640 000 births, although it may be higher in Saguenay-Lac-St Jean, a French Canadian isolate. (Ekstrand & Sankar, 2009, p. 603)

Are lysosomal storage illnesses common in eastern Quebec for the same reason that they are common among Ashkenazi Jews? At first thought, the idea may seem absurd. Weren’t French Canadians historically a nation of farmers? And didn’t British merchants fill all of the mentally demanding occupations?

In reality, things were not so simple. There was always a French-Canadian middle class, particularly wherever British merchants were few and far between. They were especially rare in those parts of eastern Quebec that today have high rates of Tay Sach’s (Charlevoix, Saguenay-Lac Saint-Jean, Bas Saint-Laurent). This rarity came to the notice of Alexis de Tocqueville while passing through Bas Saint-Laurent in 1831:

In this portion of Canada, one does not hear English at all. The population is only French, and yet when one encounters an inn, or a merchant, the sign is in English. (De Tocqueville, 2003, p. 185).

This lack of English competition opened up an enviable niche for French Canadians—or rather for those with the right aptitudes, especially in numeracy, literacy, and bilingualism. Elsewhere, these niches were filled by British immigrants, particularly in Montreal, Quebec City, the Eastern Townships, the Ottawa valley, and the southern and eastern shorelines of the Gaspé Peninsula.

This point is made in a study of the life of John Guay (1828-1880), a leading French Canadian merchant in the Saguenay region. To enter this occupational niche required a special mental toolkit:

Success in trade was never easy because of the competition, the fragility of the markets, and the instability of business conditions. The ablest managed to live or survive. Others, the greatest number, closed shop after a few years. Only those possessing exceptional qualities would make a fortune. (Lapointe, 1996, p. 3)

But the payoff was huge. John Guay had ten children who survived to adulthood—twice the mean reproductive success of his French Canadian contemporaries. Lapointe (1996, p. 126) attributes Guay’s success in business to the mental outlook he displayed from an early age:

The evolution of market capitalism has given rise to rules that a businessman cannot evade. One cannot simply improvise as a merchant. It takes talent and of course capital. Spontaneous generation was very uncommon in 19th-century Quebec, indeed nonexistent in John Guay’s case. The family environment in which he grew up predisposed him to develop an interest and also aptitudes for the businesses of trade, forestry, and farming. His successful career henceforth proved that a French-Canadian merchant could ably penetrate the world of business; a world where, let us remember, English Canadians controlled most of the commercial and industrial activities.

The Beauce exception

One region in eastern Quebec, however, has always been solidly French Canadian and yet has low incidences of Tay Sach’s and mucoliposes. This is Beauce County, a region south of Quebec City that covers the Chaudière valley up to the American border. Furthermore, Beaucerons are stereotyped as being self-reliant, business-minded go-getters—the “Yankees” of Quebec.

Beauce County nonetheless differs demographically from the rest of eastern Quebec in one respect. Settlement began earlier there than elsewhere, well before the Conquest. There was thus a larger pool of people and hence more individuals who could fill the niches that opened up after the Conquest, as Quebec moved from a semi-feudal mercantilist society to a more market-driven economy. Selection thus had more leeway to favor individuals who had the necessary aptitudes while not suffering the costs that lysosomal storage illnesses impose on homozygotes.

Fast evolution?

All of this might seem hard to believe. How could such selection operate over a time span of less than two centuries? Yet that is what the data tell us. Neither of these Tay Sach’s mutations is present in France. They must have gone from zero to their current high prevalence in less than ten generations.

References

Cochran, G., J. Hardy, & H. Harpending. (2006). Natural history of Ashkenazi intelligence. Journal of Biosocial Science, 38, 659-693.

De Braekeleer, M., P. Hechtman, E. Andermann, & F. Kaplan. (1992). The French Canadian Tay-Sachs disease deletion mutation: identification of probable founders, Human Genetics, 89, 83-87.
De Tocqueville, A. (2003). Regards sur le Bas-Canada, Typo.

Ekstrand J. and R. Sankar (2009). Storage Disorders, in Lisak, R.P., D.D. Truong, W.M. Carroll, & R. Bhidayasiri (eds). International Neurology. A Clinical Approach, (pp. 600-608), Wiley-Blackwell: Oxford

Frost, P. (2007). Natural selection in proto-industrial Europe, Evo and Proud, November 16.
http://evoandproud.blogspot.com/2007/11/natural-selection-in-proto-industrial.html

Lapointe, N. (1996). Le capitalisme marchand au Saguenay-Lac-Saint-Jean : John Guay (1828-1880), négociant et propriétaire foncier, Master’s thesis in regional studies for the Université du Québec à Chicoutimi, 153 p.

Murray, C. (2007). Jewish Genius. Commentary, April

Zlotogora, J. (1994). High frequencies of human genetic diseases: founder effect with genetic drift or selection? American Journal of Medical Genetics, 49, 10-13.

Hue and luminosity of human skin: a visual cue?

2011-06-11T08:33:00.001-05:00

The inferotemporal cortex is involved in both face perception and color perception. It may be in this region that the brain processes visual data on the hue and luminosity of human skin.

If you are a member of the International Society for Human Ethology, you can read my latest article: Hue and luminosity of human skin: a visual cue for gender recognition and other mental tasks.

Abstract

Face recognition takes place within a distinct heritable module of the brain and includes the ability to distinguish between male and female human faces. To identify gender, this module targets a number of sexually dimorphic features, particularly the hue and luminosity of facial skin. Men look browner and ruddier in hue because melanin and blood are more present in their skin’s outer tissues. Women have a higher luminous contrast between their facial skin and their lips and eyes. Hue seems to provide a “fast channel” for gender recognition. If the observer is too far away or the lighting too dim, the brain switches to the “slow channel” and targets luminosity. In addition to assisting gender recognition, the skin’s hue and luminosity may also alter the observer’s mental state in a number of areas, ranging from sexual attraction to emotional distancing.

Reference

Frost, P. (2011). Hue and luminosity of human skin: a visual cue for gender recognition and other mental tasks, Human Ethology Bulletin,
http://media.anthro.univie.ac.at/ISHE/index.php/bulletin/bulletin-contents

On the impossibility of blue eyes

2011-06-03T16:14:00.006-05:00

Although blue eyes are more recessive than brown eyes, eye color does not follow a simple recessive/dominant mode of inheritance. There is a wide range of intermediate hues.

As discussed in my last post, one puzzle of human evolution is the diverse palette of European hair and eye colors. Although these two polymorphisms have largely developed at separate genes, they share a similar geographic range and similar conspicuous hues. They also appear on or near the face—the focus of human visual attention. Could a common selection pressure be responsible? And could it be sexual selection?

This topic came up a month ago on Steve Sailer’s blog, specifically the evolution of blue eyes. Greg Cochran pointed out that sexual selection could not be responsible because blue eyes are recessive:

First, an advantageous allele whose action is purely recessive is far more likely to be lost when new than a dominant allele with an equivalent advantage. Second, assuming that it is not lost and that the population mates randomly, it takes much longer to reach 50% frequency than a dominant allele. Third, if the population is spread out over space, the Fisher wave spreads far more slowly, something like 20 times more slowly.

Mutations are fairly common, but a potentially adaptive one—like an allele for blue eyes—is usually rare. In this case, the same rare allele must occur twice and come together in the same person before sexual selection can do its work. And this work would be lost in the next generation.

All of this assumes, of course, that blue eyes are recessive. Although eye color is polygenic, alleles at two STPs (rs12913832 and rs1129038) seem to account for most cases of blue eyes (Eiberg et al., 2008). In a Polish sample, 89% of the blue-eyed individuals had both copies of the ‘C’ allele at rs12913832 and no copies of the alternate ‘T’ allele (Branicki et al., 2009).

But the C allele is far from silent if only one copy is present, as seen in the same Polish sample. Among CT heterozygotes, 16% had blue or grey eyes, 10% green eyes, 47% hazel eyes, and only 27% brown eyes.

Although the C allele is relatively recessive for expression of blue eyes, it shows strong heterozygote effects for expression of green or hazel eyes:

Blue or grey-eyed individuals: 89% had both copies, 10% one copy, 9% no copies
Green-eyed individuals: 67% had both copies, 30% one copy, 2% no copies
Hazel-eyed individuals: 9% had both copies, 80% one copy, 11% no copies
Brown-eyed individuals: 0% had both copies, 84% one copy, 16% no copies

In short, the C allele is less dominant, but not truly recessive. Even in the heterozygous state, it usually produces hues that visibly diverge from the human norm of brown eyes.

Greg also forgets that evolution can reach an initially inaccessible state by passing through intermediate states. When the C allele first appeared, it produced only green or hazel eyes for sexual selection to act upon. As copies of this allele increased in the population, there was a corresponding increase in the probability of homozygotes that could produce blue eyes—which became a new target for sexual selection.

The selection here is not for a single color, be it blue, green, hazel, or brown, but rather for any colors that can catch attention by their novelty or brightness. The end result is more and more eye colors—a balanced polymorphism where sexual selection is always on the lookout for new and interesting hues. Needless to say, this outcome is possible only when the operational sex ratio is very lopsided, thus favoring the evolution of ‘eye candy’ among members of the sex in excess supply.

References

Branicki, W., U. Brudnik, and A. Wojas-Pelc. (2009). Interactions between HERC2, OCA2 and MC1R may influence human pigmentation phenotype, Annals of Human Genetics, 73,160–170.

Eiberg, H., J. Troelsen, M. Nielsen, A. Mikkelsen, J. Mengel-From, K.W. Kjaer, & L. Hansen. (2008). Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression, Human Genetics, 123, 177–187

Sailer, S. (2011). Old Blue Eyes, May 10
http://isteve.blogspot.com2011/05/old-blue-eyes.html

Is eye color sex-linked?

2011-05-27T15:08:00.007-05:00

Averaged face of blue-eyed male subjects (left). Averaged face of brown-eyed male subjects (right). Czech population. (Kleisner et al., 2010)

If sexual selection of women diversified the eye color of early Europeans, the new colors should tend to be sex-linked, since the selection targeted women more than men. There is now evidence that blue eyes are linked to feminization of face shape.

Throughout most of the world, humans have brown eyes, black hair, and varying shades of dark skin. An exception is Europe, especially its northern and eastern portions. Here, eyes are not only brown but also blue, gray, hazel, or green. Hair is not only black but also brown, flaxen, golden, or red. Finally, skin has been whitened to the end point of depigmentation.

How can we explain this unusual color pattern? Is it simply due to lightening of skin color? In other words, did reduction of skin pigmentation incidentally reduce eye and hair pigmentation? The diverse palette of eye and hair colors would thus be a side effect of selection for lighter skin.

This explanation is dubious. For one thing, the gene loci are not the same. European skin has whitened mainly through allelic change at SLC45A2 (AIM1) and SLC24A5 (Soejima et al., 2005; Voight et al., 2006). European hair has diversified in color through a proliferation of new alleles at MC1R (Makova & Norton, 2005; Rana et al., 1999). European eyes have diversified in color mainly through a proliferation of new alleles at the OCA2-HERC2 gene complex (Duffy et al., 2007; Kayser et al., 2008; Sturm & Frudakis, 2004; Sturm et al., 2008).

Some of these novel hair and eye colors are also associated with lighter skin, notably the red hair and blue eye phenotypes. But why would selection for lighter skin lead to a proliferation of new alleles for hair and eye color—most of which have little or no influence on skin color? Why is it that red hair and blue eyes have not reached fixation in any human population, even those with milk-white skin?

Sexual selection?

I have argued that the cause was an intensification of sexual selection among early Europeans, specifically sexual selection of women (Frost, 2006; Frost, 2008). When too many women have to compete for too few men, there is selection for visible female traits that hyperstimulate certain algorithms in the male brain, particularly those for gender recognition or fertility assessment.

Among hunter-gatherers—and all humans were hunter-gatherers until 10,000 years ago, sexual selection of women tends to intensify farther away from the equator. On the one hand, hunting distances lengthen, thus increasing male mortality. On the other, polygyny becomes less common because women are less able to provide for themselves and their children in winter, thus making it costlier for a man to provide for a second wife. Result: a growing imbalance between the numbers of women and men on the mate market.

Among early modern humans, these two equator-to-arctic trends reached a common end-point in the steppe-tundra of northern Eurasia, such as existed during the last ice age (25,000 – 10,000 years ago). Hunting distances were very long because almost all food came from highly mobile herds of mammals, notably reindeer. Male provisioning was similarly at a maximum, women having little or no food autonomy.

The Eurasian steppe-tundra was continuously inhabited only in portions of its European end, where it ran farther south because of the large icecap over Scandinavia and where the moderating influence of the Atlantic Ocean and the Gulf Stream made the climate moister and milder. Here, the effects of intense sexual selection could accumulate and be passed on from generation to generation. Conversely, northern Asia appears to have suffered episodes of complete depopulation, particularly at the height of the last ice age.

Sexual selection: color novelty and color diversification

When sexual selection is weak, the adaptive equilibrium is dominated by selection for a dull, cryptic appearance that reduces detection by predators (Kirkpatrick, 1987). As sexual selection grows stronger, the equilibrium shifts toward a more noticeable appearance that retains the attention of potential mates, typically by means of vivid and/or novel colors.

One outcome may be a polymorphism of brightly colored phenotypes, due to selection shifting to scarcer and more novel hues whenever a color variant becomes too common (Endler, 1980; Frost, 2006; Hughes et al., 1999; Hughes et al., 2005; Olendorf et al., 2006). This frequency dependence has been shown in humans. Thelen (1983) presented male participants with slides showing attractive brunettes and blondes and asked them to choose, for each series, the woman they would most like to marry. One series had equal numbers of brunettes and blondes, a second 1 brunette for every 5 blondes, and a third 1 brunette for every 11 blondes. Result: the rarer the brunettes were in a series, the likelier any one of them would be chosen.

But why would this stronger selection diversify hair and eye color while simply whitening skin color? The answer seems to be that sexual selection acts on skin color not only through rare-color preference but also by hyperstimulating a gender-recognition algorithm, i.e., by accentuating a visible female-specific trait. In our species, female skin has less melanin and hemoglobin than does male skin, i.e., women look paler, men browner and ruddier (Edwards & Duntley, 1939; Hulse, 1967; Jablonski & Chaplin, 2000).

Sex linkage?

If European skin had whitened through selection for lighter-skinned women, it should have whitened more in women than in men, thus becoming more sexually dimorphic. Yet skin color actually seems to be less dimorphic in Europeans than in other humans (Madrigal & Kelly, 2006). This finding does not necessarily invalidate the sexual selection hypothesis. It may be that the pigmentary sex difference cannot fully express itself in light-skinned populations. Skin color is dimorphic because girls progressively lighten in color during adolescence, and such lightening may be less easily expressed if melanin production is already low. Indeed, this dimorphism seems to be almost absent in people whose skin starts off with very little pigment, such as Dutch and Belgian subjects (Frost, 2007).

And hair and eye color? Sexual selection of women should favor novel hair and eye colors more so in women than in men. Granted, both polymorphisms arose over a short and relatively recent span of time, so sexual selection would have worked with those alleles that were initially available and, for the most part, not sex-linked. But surely a few of these mutant alleles would have been sex-linked and, as such, favored over non-sex-linked ones.

This does seem to be the case with hair color. Blond hair darkens with age more slowly in women than in men (Olivier, 1960, p. 74). A ‘digit ratio’ study indicates that prenatal exposure to estrogen is higher in individuals with blond hair or non-brown eyes (Mather et al., unpublished). The same study, however, found no evidence of sexual dimorphism. Women and men had roughly the same proportions of hair and eye colors among the 18-to-38 year olds under study. Such a dimorphism, if it does exist, may be a transient one limited to younger age groups.

Moreover, Kleisner et al. (2010) have found an apparent sex linkage between blue eyes and feminization of face shape. They initially wished to determine whether eye color influences perception of male dominance, using facial pictures of Czech men. The results showed that brown-eyed men were rated as more dominant than blue-eyed men. As a control, the authors repeated the experiment after altering the facial photos of the brown-eyed men to make them blue-eyed. These altered photos were still rated as more dominant.

Careful study of the photos revealed that the brown-eyed men had more masculine facial features:

In contrast with blue-eyed males, brown-eyed males have statistically broader and rather massive chins, broader (laterally prolonged) mouths, larger noses, and eyes that are closer together with larger eyebrows. In contrast, blue-eyed males show smaller and sharper chins, mouths that are laterally narrower, noses smaller, and a greater span between the eyes.

The perception of brown-eyed men as more dominant is thus due to their more masculine facial appearance—and not to their brown eyes. The authors suggest that some kind of sex linkage may be responsible, while adding: “Repeating this study in other populations with polymorphism in eye color can test this hypothesis.”

If true, this finding would be consistent with Liberton et al. (2009) who found that European face shape has differentiated from West African face shape through a selective force that has acted primarily on women. Both findings, in turn, would support my argument that many of the differences we see among human populations are not due to differences in natural selection, and hence differing natural environments. Instead, the cause lies in differing intensities of sexual selection, and whether this selection has primarily targeted men or women (Frost, 2008).

When men are the prime targets of sexual selection, as in tropical ‘female farming’ societies, the result is accentuation of certain male features. Meanwhile, there is a slackening of female-targeted sexual selection, which leads to women having a more functional and less ornamental appearance. This pattern is reversed when women are the prime targets of sexual selection (Frost, 2008).

Ethnic substructure?

There is admittedly an alternate explanation for the above finding: ethnic substructure among the Czech subjects. The Czech Republic has historically been home to ethnic minorities who statistically differ from ethnic Czechs in facial appearance, i.e., Jews, Germans, and Roma. Jews and Roma, like other populations of Mediterranean or southwest Asian origin, tend to have brown eyes and a more robust face shape. Conversely, Germans are likelier to have blue eyes and more gracile faces. Although the Jewish and German communities were severely decimated during World War II and its aftermath, with many survivors later emigrating, there still remain significant numbers of Czech citizens who are wholly or partly of Jewish or German origin. Since WWII, there has also been an influx of Roma into the Czech Republic.

It would be difficult to rule out this kind of explanation, even if one questioned the subjects of the study. After the last war, many Czech citizens of Jewish or German origin felt it best to conceal their ancestry, for fear of discrimination or even expulsion from the country. Today, their grandchildren may be completely unaware of their origins.

This is all the more reason to replicate the results with subjects from another population, preferably one with as little ethnic substructure as possible.

References

Duffy, D.L., G.W. Montgomery, W. Chen, Z.Z. Zhao, L. Le, M.R. James, N.K. Hayward, N.G. Martin, & R.A. Sturm. (2007). A three-single-nucleotide polymorphism haplotype in intron 1 of OCA2 explains most human eye-color variation. American Journal of Human Genetics, 80, 241-52.

Edwards, E.A., & S.Q. Duntley. (1939). The pigments and color of living human skin. American Journal of Anatomy, 65, 1-33.

Endler, J.A. (1980). Natural selection on color patterns in Poecilia reticulata. Evolution, 34, 76‑91.

Frost, P. (2008). Sexual selection and human geographic variation, Special Issue: Proceedings of the 2nd Annual Meeting of the NorthEastern Evolutionary Psychology Society. Journal of Social, Evolutionary, and Cultural Psychology, 2(4),169-191.

http://www.jsecjournal.com/articles/volume2/issue4/NEEPSfrost.pdf

Frost, P. (2007). Comment on Human skin-color sexual dimorphism: A test of the sexual selection hypothesis, American Journal of Physical Anthropology, 133, 779-781.

Frost, P. (2006). European hair and eye color - A case of frequency-dependent sexual selection? Evolution and Human Behavior, 27, 85-103.

Hughes, K.A., L. Du, F.H. Rodd, & D.N. Reznick. (1999). Familiarity leads to female mate preference for novel males in the guppy, Poecilia reticulata. Animal Behaviour, 58, 907-916.

Hughes, K.A., F.H. Rodd, & D.N. Reznick. (2005). Genetic and environmental effects on secondary sex traits in guppies (Poecilia reticulata). Journal of Evolutionary Biology, 18, 35-45.

Hulse, F.S. (1967). Selection for skin color among the Japanese. American Journal of Physical Anthropology, 27, 143-156.

Jablonski, N.G., & G. Chaplin. (2000). The evolution of human skin coloration. Journal of Human Evolution, 39, 57-106.

Kayser, M., F. Liu, A.C.J.W. Janssens, F. Rivadeneira, O. Lao, K. van Duijn, M. Vermeulen, P. Arp, M.M. Jhamai, W.F.J. van Ijcken, J.T. den Dunnen, S. Heath, D. Zelenika, D.D.G. Despriet, C.C.W. Klaver, J.R. Vingerling, P.T.V.M. de Jong, A. Hofman, Y.S. Aulchenko, A.G. Uitterlinden, B.A. Oostra, & C.M. van Duijn. (2008). Three genome-wide association studies and a linkage analysis identify HERC2 as a human iris color gene. The American Journal of Human Genetics doi:10.1016/j.ajhg.2007.10.003

Kirkpatrick, M. (1987). Sexual selection by female choice in polygynous animals. Annual Review of Ecology and Systematics, 18, 43-70.

Kleisner, K., T. Kočnar, A. Rubešova, and J. Flegr. (2010). Eye color predicts but does not directly influence perceived dominance in men, Personality and Individual Differences, 49, 59–64.

Liberton, D.K., K.A. Matthes, R. Pereira, T. Frudakis, D.A. Puts, & M.D. Shriver. (2009). Patterns of correlation between genetic ancestry and facial features suggest selection on females is driving differentiation. Poster #326, The American Society of Human Genetics, 59th annual meeting, October 20-24, 2009. Honolulu, Hawaii.

Mather, F., J.T. Manning, & P.E. Bundred. (unpublished). 2nd to 4th digit ratio, hair and eye colour in Caucasians: Evidence for blond hair as a correlate of high prenatal oestrogen.

Makova, K, & H. Norton. (2005). Worldwide polymorphism at the MC1R locus and normal pigmentation variation in humans. Peptides, 26, 1901-1908.

Olendorf, R., F.H. Rodd, D. Punzalan, A.E. Houde, C. Hurt, D.N. Reznick, & K.A. Hughes. (2006). Frequency-dependent survival in natural guppy populations. Nature, 44, 633-636.

Olivier, G. (1960). Pratique anthropologique. Paris: Vigot Frères.

Rana, B.K., D. Hewett‑Emmett, L. Jin, B.H.-J. Chang, N. Sambuughin, M. Lin, S. Watkins, M. Bamshad, L.B. Jorde, M. Ramsay, T. Jenkins, & W-H. Li. (1999). High polymorphism at the human melanocortin 1 receptor locus. Genetics, 151, 1547‑1557.

Soejima, M., H. Tachida, T. Ishida, A. Sano, & Y. Koda. (2005). Evidence for recent positive selection at the human AIM1 locus in a European population. Molecular Biology and Evolution, 23, 179-188.

Sturm, R.A., D.L. Duffy, Z.Z. Zhao, F.P.N. Leite, M.S. Stark, N.K. Hayward, N.G. Martin, & G.W. Montgomery. (2008). A single SNP in an evolutionary conserved region within intron 86 of the HERC2 gene determines human blue-brown eye color. The American Journal of Human Genetics, 82, 424-431.

Sturm, R.A., & T.N. Frudakis. (2004). Eye colour: portals into pigmentation genes and ancestry. Trends in Genetics, 20, 327-332.

Thelen, T.H. (1983). Minority type human mate preference. Social Biology, 30, 162-180.

Voight, B.F., S. Kudaravalli, X. Wen, & J.K. Pritchard. (2006). A map of recent positive selection in the human genome. PLoS Biology, 4(3), e72 doi:10.1371/journal.pbio.0040072

The demon within. Part III

2011-05-20T15:02:00.005-05:00

Sir John Hawkins (1532-1595) was instrumental in bringing England into the slave trade. Was this trade a source of new pathogens for the English population?

Some vaginal strains of Candida albicans have become better at sexual transmission, such as through improved adhesion to saliva-coated surfaces and through displacement of non-vaginal strains in a new host.

But the adaptations don’t stop there. In my last two posts, I argued that these strains have also become better at sexual transmission by manipulating host behavior. They can cross the blood/brain barrier. We know this. Once inside the control room, why not go one step farther?

C. albicans is an ideal candidate for such evolution. First, It’s common. There’s a large pool of genetic variants for natural selection to act upon.

Second, C. albicans has developed the capacity to spread from one host to another through intimate contact. It thus has every reason to enhance this capacity by rewiring its host’s neural circuits, even at the cost of doing much harm.

As biologist Paul Ewald observed:

For decades medical science was dominated by the doctrine of "commensalisms' - the notion that the pathogen-host relationship inevitably evolves toward peaceful coexistence, and the pathogen itself toward mildness, because it is in the germ's interest to keep its host alive. This sounds plausible, but it happens to be wrong.

[…] If you're a germ that can travel from person to person by way of a "vector," or carrier, such as a mosquito or a tsetse fly, you can afford to become very harmful. This is why, Ewald argues, insect borne diseases such as yellow fever, malaria, and sleeping sickness get so ugly. Cholera uses another kind of vector for transmission: it is generally waterborne, travelling easily by way of faecal matter shed into the water supply. And it, too, is very ugly. (Hooper, 1999)

An infectious organism will thus try to turn its host into a launching pad for infection of other hosts. The long-term survival of any one host no longer matters.

Avenues for future enquiry

Where from?

If a pathogen is responsible for cuckold envy, and if the first recorded mention of this fetish comes from 17th-century England, the point of origin is probably extra-European. Specifically, it would have been a society that came into contact with England through that country’s expansion of foreign trade, exploration, and colonization from the 16th century onward. We’re probably looking at the West Indies, West Africa, the eastern American seaboard, or the territories of the Hudson’s Bay Company.

One of my commenters, Jim Bowery, suggested that the pathogen could have entered England via the West African slave trade. Indeed, an argument can be made that sexually transmitted diseases are most likely to develop in high-polygny societies, such as exist among the ‘female-farming’ peoples of sub-Saharan Africa. On the one hand, the polygynous male cannot sexually satisfy all of his wives. On the other, many young males are locked out of the marriage market, the result being a lot of sex on the sly.

As anthropologist Pierre van den Berghe pointed out:

The temporary celibacy of young men in polygynous societies is rarely absolute, however. While it often postpones the establishment of a stable pair-bond and the procreation of children, it often does not preclude dalliance with unmarried girls, adultery with younger wives of older men, or the rape or seduction of women conquered in warfare. Thus, what sometimes looks like temporary celibacy is, in fact, temporary promiscuity. (van den Berghe, 1979, pp. 50-51).

Do other STDs manipulate human sexual behavior?

Is manipulation of sexual behavior a logical adaptation for STDs? If so, have other human STDs evolved in this direction? No one seems to have asked the question. Admittedly, cause and effect are hard to tease apart. Do STDs correlate with sexual promiscuity solely because a promiscuous person is more likely to catch one? Which is the chicken and which is the egg?

Research on insects has turned up several cases of an STD manipulating host behavior in order to facilitate sexual transmission.

Behavioural changes associated with parasitic infection are well known, and at least some of these appear to be adaptations on the part of the parasite to increase transmission (Moore, 1993, 2001; Poulin, 1994a, b, 1998a, 2000). Four recent studies of insect STDs are relevant here. McLachlan (1999) showed that male midges (Paratrichocladius rufiventris) infected with the mite Unionicola ypsilophora were more likely to be in mating pairs than uninfected males. As discussed earlier, the mites rely on female midges to return them to water to complete their life cycle. If they find themselves on a male midge, therefore, they are effectively dead unless their host mates with a female […].

Raina et al. (2000) found that Hz-2V infected female corn earworm moths Helicoverpa zea produce two to three times more sex pheromone than uninfected female moths, possibly enhancing their ability to attract male moths, although they also reported that these animals vigourously resisted mating. Abbot & Dill (2001) found that male Labidomera clivicollis beetles infected with the mite Chrysomelobia labidomera were more likely to displace other males from mating pairs, which again could be interpreted as being adaptive manipulation of the host by the parasite to increase transmission. Webberley et al. (2002), by contrast, found that infection of Adalia bipunctata with Coccipolipus hippodamiae did not have any effect on the mating behaviour of the host. (Knell & Webberley, 2004)

References

Hooper, J. (1999). A new germ theory, The Atlantic Journal, February

http://gc.homeunix.net/

Knell, R.J., and K.M. Webberley. (2004). Sexually transmitted diseases of insects: distribution, evolution, ecology and host behaviour, Biol. Rev., 79, 557–581.

van den Berghe, P.L. (1979). Human Family Systems. An Evolutionary View, New York: Elsevier.

The demon within. Part II

2011-05-13T15:08:00.008-05:00

Preferential binding by Candida albicans to various types of cells in a macaque brain (Denaro et al., 1995).

In my last post, I examined the relationship between sexual behavior and vulvovaginal candidiasis (VVC), a condition that occurs when certain strains of vaginal yeast (Candida albicans) become highly virulent. Clearly, the relationship is not a simple one of cause and effect. Occurrence of VVC correlates not with vaginal sex but rather with non-vaginal sex, i.e., fellatio, cunnilingus, and masturbation. There is also no significant association between VVC and the presence of C. albicans in the male partner, including his oral cavity.

The evidence suggests that the direction of causality runs in the opposite direction. These strains of C. albicans do not enter a woman’s vagina via fellatio, cunnilingus, or masturbation, at least not primarily. Instead, they may be manipulating the host’s behavior by weakening her sexual inhibitions and inciting her to maximize contact between vaginal fluids and colonizable sites on her partner’s body.

This scenario is all the more likely because vaginal yeast is common and thus provides a large pool of organisms for natural selection to act upon. Vaginal strains of C. albicans also show evidence of adaptation to saliva-based transmission, i.e., they adhere better to saliva-coated surfaces than do other strains (Schmid et al., 1995). In the male partner, they tend to displace non-vaginal strains (Schmid et al., 1993).

So these vaginal strains became better at spreading from a female host to a new male host. But what then?

Did they then evolve the capacity to make the male host more sexually promiscuous? Perhaps. But keep in mind that male-to-female transmission is much less effective than female-to-male transmission. Although VVC can develop on male body sites, the vagina is by far the primary site for C. albicans colonization and infection.

From the standpoint of C. albicans, the optimal scenario would be one where the female host goes on to infect other males. What can her regular male partner do to bring this about?

He could cease all mate-guarding behavior. In plain English, he could stop being jealous. He could even encourage her to have sex with other men.

This kind of parasite manipulation does occur in one organism, the isopod Caecidotea intermedius. A parasite, Acanthocephalus dirus, infects this isopod as an intermediate host in order to enter its final host, one of several freshwater fishes. When the parasite is still soft and immature, it cannot survive a fish eating its isopod host. It thus seeks to reduce this risk by suppressing conspicuous host behaviors, like mate guarding. Later, when the parasite becomes hard and mature, it can survive consumption of its host and, in fact, seeks this outcome. It now stimulates conspicuous behaviors, like mate guarding, and changes its host’s pigmentation to increase visibility (Mormann, 2010).

‘Cuckold envy’

In humans, suppression of mate guarding seems to match a behavior called “cuckold envy”—a sexual fetish where a man is not only indifferent to being cuckolded but actually derives pleasure from cuckoldry. How prevalent is this fetish? A Google search for the term “wife breeding” turned up 793,000 hits, many of which corresponded to videos that have been specially developed for this market.

Cuckold fetishists tend to center their fantasies on black men, perhaps because darker skin and heavier facial features help evoke the image of a rival male. In fact, some of these fetishists have rebranded themselves as members of the “interracial community,” presumably to gain social acceptance and to blend into the broader antiracist movement. Such individuals may be behind the apparent mainstreaming of interracial porn, as seen for example in the antiracist Swedish video Blanda Upp! (2010). One might draw parallels here between lesbian activists and the feminist movement …

This sexual fetish seems to be sufficiently common to foster speculation about a possible Darwinian (or pseudo-Darwinian) cause:

In his book Sperm Wars, biologist Robin Baker speculated that the excitement and stimulation of the cuckolding fetish emerges from the biology of sexuality and the effects of sexual arousal on the brain. According to his theory, when a man believes that his female mate may have been sexual with another man, he is prompted by biological urges to copulate with the female, in an effort to "compete" with the other man's sperm. (Cuckold – Wikipedia)

Baker’s theory fails to explain why most men have precisely the opposite emotional reaction, i.e., feelings of hurt, anger, and rage.

This seems to be true in all human societies. A search for the term ‘cuckold’ in the Human Relations Area Files (HRAF) turned up references to 32 cultures. All of the references indicated intensely negative feelings in the cuckolded men, as seen in the following examples:

Yanomamö (South America)
Discovery of liaisons by the cuckold inevitably leads to club fighting between the factions of the lover and the husband. The woman involved usually suffers more than either of the male principals in the fighting that follows, as women are severely punished by their husbands. The punishment usually consists of a beating with a club, but men frequently shoot their unfaithful wives with barbed arrows in a non-vital area of the body, such as the buttocks or leg. In one instance I witnessed, the enraged husband struck his wife in the face with a burning log, severely burning her mouth. Burning is a common punishment, and many women bear immense scars from wounds inflicted by enraged husbands. (Chagnon, 1967, pp. 91-92)

Tukano (South America)
Adultery or even flirting with a ceremonial friend’s spouse is a principal cause for a break in this otherwise very stable relationship. A ceremonial friend who has been wronged by his partner retaliates by entering the offender’s house to break or carry off everything belonging to him except the hammock. This act of vandalism declares the friendship broken. Eternal animosity succeeds it. (Goldman, 1963, p. 132).

Quechua (South America)
The two strongest insults that Saraguro males can fling at each other (or curse behind their backs) are maricón (homosexual) and cabrón (literally, he-goat, but meaning cuckold). (Belote, 1978, p. 79)

Pashtun (Asia)
[…] for daows (“cuckold” and by extension “dupe”) is the most serious curse and adultery rather than incest the crime of horror. Among the most serious offenses against Pakhtun social order, adultery causes more trouble, mobilizes more sanctions, and ramifies further than any other Pakhtun delict. (Anderson, 1982, p. 401)

Greeks (Europe)
Conversely, the act of disobedience by which she damages her husband most severely is adultery. In adultery she makes her husband a cuckold (κερατ□ς), one who wears a horn. ‘She puts horns on him’ (το□ βάζει κέρατα), it is said. The implication that the cuckold wears a horn may be an ironical allusion to the sexual potency which his wife's action suggests he does not possess (Campbell, 1964, p. 152)

Azande (Africa)
[…] he is certain that she has a lover and he broods in dark anger till he can discover who has made him a cuckold. (Evans-Pritchard, 1937, p. 268)

Men seem to tolerate cuckoldry the most in societies with low paternal investment, i.e., ‘female farming’ societies of sub-Saharan Africa and Papua-New Guinea. But I found no HRAF reference to men actually feeling pleasure at the idea of being cuckolded. The closest match was the custom of ‘wife exchange’ among the Inuit and some Amerindian peoples, like the Comanche:

In many cases, the levirate as practiced by the Comanches approximated polyandry, for brothers lent each other their wives. This “anticipatory levirate” reflected an attitude of camaraderie and denial of sexual jealousy between two brother-warriors.

[…] Women, however, were not free to initiate liaisons. Adulterous men could be sued for damages and customarily made payments in horses or other goods, but the women in question bore the brunt of the shame, and her punishment might include disfigurement (usually slitting of the nose) or death at the hands of her husband. When pressing his case, the cuckold would address his wife's lover as “brother,” an ironic reference to the proper conditions for wife sharing. (Gelo, 1986, pp. 29-30)

When I switched from a cross-cultural search to a cross-historical one, the oldest references to cuckold envy seemed to be in plays from 17th-century England. In these plays, the cuckold anxiety of earlier periods gives way to cuckold envy:

In A Mad World, My Masters Middleton fully realizes some of the subtle psycho/social details that Jonson develops with the potential cuckold Kitely in Every Man in His Humor. The perverse pleasure that Jonson's acquiescent cuckold derives from his subject position is latent, as Martin Semour-Smith notes, in the etymology of Kitely's name: "Mr. Sale draws attention in his edition to the dialect word 'kittle', meaning 'ticklish' ie. 'hard to deal with, touchy'; but he has missed the verb 'to kittle': 'to stir, with feeling or emotion, usually pleasurable.'" Seymour-Smith continues, noting that it "was also clear to Jonson that Kitely perversely enjoyed his wife less as a direct sexual object than as the indirect object by which he might be cuckolded" (xii, xiii). (Kuchar, 2001, p. 18)

In Every Man in His Humor, the lead character notes the strangeness of his fetish:

Who will not judge him worthy to be robbed,
That sets his doors wide open to a thief,
And shows the felon, where his treasure lies?
(Kuchar, 2001, p. 19)

If 17th-century England is the ground zero for cuckold envy, where was it beforehand? In some yet unknown human population? Or was it in a nonhuman species? Perhaps we are looking at an evolutionary trajectory similar to that of the AIDS virus, i.e., a lengthy period of co-adaptation in a nonhuman population followed by transfer to a human population and increased virulence.

References

Anderson, J.W. (1982). Social structure and the veil: comportment and the composition of interaction in Afghanistan, Anthropos, 77 (3/4), 397.

Belote, L. (1978). Prejudice and pride: Indian-White relations in Saraguro, Ecuador,
Ann Arbor, Michigan: University Microfilms International.

Campbell, J.K. (1964). Honour, family and patronage: a study of institutions and moral values in a Greek mountain community, Oxford: Clarendon Press.

Chagnon, N. (1967). Yanomamö warfare, social organization and marriage alliances,
Ann Arbor, Mich.: University Microfilms.

Cuckold – Wikipedia, http://en.wikipedia.org/wiki/Cuckold

Denaro, F.J., J.L. Lopez-Ribot, and W.L. Chaffin. (1995). Adhesion of Candida albicans to brain tissue of Macaca mulata in an ex vivo assay, Infection and Immunity, 63, 3438-3441.

Evans-Pritchard, E.E. (1937). Witchcraft, oracles and magic among the Azande,
Publisher: Oxford: Clarendon Press.

Gelo, D. (1986). Comanche belief and ritual, Ann Arbor, Mich.: University Microfilms International.

Goldman, I. (1963). The Cubeo: Indians of the Northwest Amazon, Urbana, Illinois: University of Illinois Press.

Kuchar, G. (2001). Rhetoric, Anxiety, and the Pleasures of Cuckoldry in the Drama
of Ben Jonson and Thomas Middleton, Journal of Narrative Theory, 31 (1), Winter, pp. 1-30.

Mormann, K. (2010). Factors influencing parasite-related suppression of mating behavior in the isopod Caecidotea intermedius, Theses and Disserations, paper 48
http://via.library.depaul.edu/etd/48

Schmid, J., P.R. Hunter, G.C. White, A.K. Nand, and R.D. Cannon. (1995). Physiological traits associated with success of Candida albicans strains as commensal colonizers and pathogens, Journal of Clinical Microbiology, 33, 2920–2926.

Schmid, J., M. Rotman, B. Reed, C.L. Pierson, and D.R. Soll. (1993). Genetic similarity of Candida albicans strains from vaginitis patients and their partners, Journal of Clinical Microbiology, 31, 39-46.

The demon within

2011-05-06T12:05:00.013-05:00

Candida albicans. Some strains have adapted to sexual transmission. Have they gone so far as to manipulate host behavior?

Vulvovaginal candidiasis (VVC), commonly known as vaginal yeast infection, affects 70-75% of sexually active women at least once and 5-8% recurrently (Li et al., 2008). It is usually caused by Candida albicans, a single-celled fungus that reproduces asexually.

Although C. albicans can colonize many body sites, some strains have specifically adapted to the vagina. This evolutionary trajectory seems to have gone through three levels of adaptation:

Adaptation to vaginal environments

Vaginally adapted strains are a small subset of C. albicans. In China, two strains account for almost 60% of all VVC cases, yet neither is present at extragenital sites (Li et al., 2008). In the United States, C. albicans strains are much more diverse in the male partners of women without VVC than in the vaginas of women with or without VVC (Schmid et al., 1993).

Adaptation to sexual transmission

These vaginal strains seem to have also adapted to sexual transmission, specifically female-to-male transmission. Once VVC develops, they can spread to the host’s male partner by colonizing his glans penis via vaginal intercourse (Li et al., 2008) or his oral cavity via cunnilingus (Schmid et al., 1995). Vagina-to-vagina transmission has also been attested in lesbian couples (Bailey et al., 2008).

There is evidence of genetic changes for sexual transmissibility. Vaginal strains adhere better to saliva-coated surfaces than do other strains (Schmid et al., 1995). In the male partner, they tend to displace non-vaginal strains of C. albicans (Schmid et al., 1993).

Adaptation to certain sexual behaviors

Although a relationship clearly exists between sexual behavior and VVC, it is not a simple one of cause and effect. This is the conclusion of two research teams, Hellberg et al. (1995) and Reed et al. (2003), who sought to identify those aspects of sexual behavior that correlate with VVC.

Hellberg et al. (1995) found no significant association between VVC and the main indicators of vaginal sexual activity: (1) frequency of vaginal sex; (2) history of multiple sexual partners (more than 10 lifetime partners); and (3) sex with more than one partner during the last six months.

There were, however, significant associations with (1) early age of first intercourse, (2) casual sex with previous unknown partners in the past month, (3) vaginal sex during menstruation, (4) oral sex (fellatio), and (5) receptive anal sex.

Reed et al. (2003) reported similar findings. VVC was not significantly associated with frequency of vaginal sex, lifetime number of partners, and duration of current relationship. But there were significant associations with cunnilingus in the past month and masturbation in the past month. Unlike Hellberg et al. (1995), there were no significant associations with early age of first intercourse or frequency of receptive anal sex.

Reed et al. (2003) also found two risk factors in the male partner: early age of first intercourse and masturbation in the past month. There were no significant associations with his marital status, lifetime number of partners, previous partners with VVC, personal history of yeast infections, or reported fellatio or cunnilingus in the past month.

This is all rather puzzling. Occurrence of VVC was related not to vaginal sex but rather to non-vaginal sex, i.e., fellatio, cunnilingus, and masturbation. Even more puzzling, Reed et al. (2003) failed to find any association between VVC and the presence of C. albicans in the male partner, including his oral cavity. The authors concluded that the relationship between VVC and sexual behavior is not primarily one of sexual transmission:

If the association between orogenital contact and recurrent Candida vulvovaginitis is not mediated by transmission of the organism, how might increased risk be conferred? Previous study of the immunopathogenesis of recurrent Candida vulvovaginitis suggests that a delicate equilibrium exists among C. albicans, vaginal bacterial flora, and vaginal defense mechanisms, and that changes in the host environment promote the transformation of C. albicans from a saprophytic to a pathogenic existence. We suggest that the effects of genital washing with saliva—from either the male or the female—might upset this balance […] (Reed et al., 2003)

But how would this vaginal equilibrium be upset by the woman fellating her male partner? And how would it be upset by her male partner masturbating—alone and by himself?

Manipulation of host behavior?

To make sense of all this, we should perhaps reverse the direction of causality. Perhaps some vaginal strains of C. albicans have reached a third level of adaptation, i.e., manipulation of host behavior to increase opportunities for sexual transmission. Perhaps they somehow weaken the host’s sexual inhibitions and incite her to maximize contact between her vaginal fluids and colonizable sites on her partner’s body.

Does this sound like science fiction? Keep in mind that parasites manipulate host behavior in many non-human animals, and some of these parasites are likewise fungi (see here). Moreover, C. albicans has evolved the ability to cross the blood-brain barrier and colonize sites in the human brain (Jong et al., 2001). According to an autopsy of macaque brains, this microbe can recognize different kinds of neural tissue:

An ex vivo adhesion assay was used to examine adhesion of Candida albicans yeast cells to brain tissue of the primate Macaca mulata. Tissues from frontal lobes and striatum (caudate, putamen, and portions of the globus pallidus) were used in the assay. Yeast cells adhered to gray matter at about six times the level of adhesion to white matter. The fungus was able to bind to different cell types within the cortex, basal ganglia, and white matter. (Denaro et al., 1995)

One can imagine a multi-stage process of development:

1. “Behavior-modifying” C. albicans colonizes the vagina as a commensal organism with low virulence and no VVC. The ensuing period of latency might last a long time.

2. Meanwhile, the microbe spreads to other sites within the host’s body, including certain areas of the brain that influence sexual behavior.

3. Once this secondary colonization is complete, the area of primary colonization enters a highly infectious stage, i.e., VVC. The microbe is now ready to spread to her sexual partner.

And how will it influence her partner’s behavior? We cannot find the answer by studying his behavior before and during VVC—as in current studies. We must examine his subsequent behavior, i.e., once this strain of C. albicans has spread to his body and replaced other strains. Are there any behavioral changes?

But, then, what sort of changes should we expect?

(to be cont’d)

References

Bailey, J.V., R. Benato, C. Owen, and J. Kavanagh. (2008). Vulvovaginal candidiasis in women who have sex with women, Sexually Transmitted Diseases, 35, 533–536

Brainwashed by a parasite, Neurophilosophy, August 9, 2007
http://scienceblogs.com/neurophilosophy/2007/08/brainwashed_by_a_parasite.php

Denaro, F.J., J.L. Lopez-Ribot, and W.L. Chaffin. (1995). Adhesion of Candida albicans to brain tissue of Macaca mulata in an ex vivo assay, Infection and Immunity, 63, 3438-3441

Hellberg, D., B. Zdolsek, S. Nilsson, and P-A. Mårdh. (1995). Sexual behavior of women with repeated episodes of vulvovaginal Candidiasis, European Journal of Epidemiology, 1, 575-579, 1995

Jong, A.Y., M.F. Stins, S-H. Huang, S.H.M. Chen, K.S. Kim. (2001). Traversal of Candida albicans across human blood-brain barrier in vitro, Infection and Immunity, 69, 4536-4544.

Li, J., S-R. Fan, X-P. Liu, D-M Li, Z-H. Nie, F. Li, H. Lin, W-M. Huang, L-L. Zong, J-G. Jin, H. Lei, and F-Y. Bai. (2008). Biased genotype distributions of Candida albicans strains associated with vulvovaginal candidosis and candidal balanoposthitis in China, Clinical Infectious Diseases, 47, 1119–25.

Reed, B.D., P. Zazove, C.L. Pierson, D.W. Gorenflo, and J. Horrocks. (2003). Candida transmission and sexual behaviors as risks for a repeat episode of Candida vulvovaginitis, Journal Of Women’s Health, 12, 979-989.

Schmid, J., P.R. Hunter, G.C. White, A.K. Nand, and R.D. Cannon. (1995). Physiological traits associated with success of Candida albicans strains as commensal colonizers and pathogens, Journal of Clinical Microbiology, 33, 2920–2926.

Schmid, J., M. Rotman, B. Reed, C.L. Pierson, and D.R. Soll. (1993). Genetic similarity of Candida albicans strains from vaginitis patients and their partners, Journal of Clinical Microbiology, 31, 39-46.

The eternal infant

2011-04-29T13:09:00.015-05:00

“A chimpanzee’s ability to learn is drastically reduced upon reaching maturity. But baby chimps will eagerly mimic a human caretaker – sticking out their tongues, opening their mouth wide, or making their best effort at a kissy face.” (Geoff, 2009)

A newborn creature will spend much time exploring its environment. As it comes to know its surroundings, it no longer has to acquire new information at the same rate. It loses its ability to learn.

We humans are different. We never grow up. As adults, we retain this infant-like mental plasticity, much in the same way as a child’s tolerance for milk persists into adulthood in dairy-farming societies.

Geneticists are now a step closer to understanding this evolutionary change. A team led by David Kingsley of Stanford has shown that ancestral humans lost a key piece of DNA that switches on GADD45G, a gene that stifles growth of brain tissue. In non-humans, this gene regulator slows down the growth of brain tissue:

The GADD45G regulator was active in layers of the brain where cells that ultimately form the cortex are born. Specifically, in mice and chimps, GADD45G suppresses the development of brain regions which in humans are involved in higher cognitive functions like conscious thought and language."

Completely losing GADD45G would be like losing the brakes," says Kingsley. That happens in pituitary tumours when the regulator fails and cells grow without restraint, but in healthy humans the regulatory change would have only decreased activity in specific brain areas, causing them to grow larger. (Coghlan, 2011; see also McLean et al., 2011)

This kind of genetic change may largely explain how the brain progressively expanded in ancestral humans. And this evolution did not stop with the advent of Homo sapiens. Human populations today vary at several gene loci that regulate brain growth: ASPM, MCPH1, CDK5RAP2, and CENPJ. At these loci, the most recent alleles likewise seem to favor brain growth by allowing each cortical column of neurons to expand outward over a longer period of time. Interestingly, the main result does not seem to be higher IQ, but rather some other, still unknown, enhancement of mental capacity (Frost, 2008; Montgomery & Mundy, 2010; Rimol et al., 2010; Wang et al., 2008).

Differences in mental capacity should thus steadily increase from infancy to adulthood. This is an important point. If young children perform equally well on a mental task, it is often assumed that later differences must be due to differences in the learning environment.

References

Coghlan, A. (2011). Key to humanity is in missing DNA, New Scientist, March 9http://www.newscientist.com/article/mg20928033.500-key-to-humanity-is-in-missing-dna.html

Frost, P. (2008). The spread of alphabetical writing may have favored the latest variant of the ASPM gene, Medical Hypotheses, 70, 17-20.

Geoff. (2009). Chimpanzees and Neoteny, March 30.
http://www.gmilburn.ca/2009/03/30/chimpanzees-and-neoteny/

McLean, C., Reno, P., Pollen, A., Bassan, A., Capellini, T., Guenther, C., Indjeian, V., Lim, X., Menke, D., Schaar, B., Wenger, A., Bejerano, G., & Kingsley, D. (2011). Human-specific loss of regulatory DNA and the evolution of human-specific traits, Nature, 471 (7337), 216-219 DOI: 10.1038/nature09774

Montgomery, S.H. and N.I. Mundy. (2010). Brain Evolution : Microcephaly genes weigh in, Current Biology, 20(5), R244

Rimol, L.M., I. Agartz, S. Djurovic, A.A. Brown, J.C. Roddey, A.K. Kähler, M. Mattingsdal, L. Athanasiu, A.H. Joyner, N.J. Schork, et al. for the Alzheimer’s Disease Neuroimaging Initiative (2010). Sex-dependent association of common variants of microcephaly genes with brain structure. Proceedings of the National Academy of Science. USA, 107, 384–388.

Wang, J.K., Li, Y., and Su, B. (2008). A common SNP of MCPH1 is associated with cranial volume variation in Chinese population. Human Molecular Genetics, 17, 1329–1335.

The fast runners of evolution

2011-04-22T12:26:00.005-05:00

In the deer family, genetic variability is greater within some species than between some genera. Does Fst tell us what we think it tells us?

At almost any genetic marker (blood types, serum proteins, enzymes, mtDNA, etc.), a typical gene varies much more within than between human populations. And this is true not only for large continental populations but also for small local ones. The geneticist Richard Lewontin found that 85% of our genetic variation exists among individuals and only 15% between ‘races.’ He concluded:

It is clear that our perception of relatively large differences between human races and subgroups, as compared to the variation within these groups, is indeed a biased perception and that, based on randomly chosen genetic differences, human races and populations are remarkably similar to each other, with the largest part by far of human variation being accounted for by the differences between individuals. (Lewontin, 1972)

Was Lewontin right? Some geneticists have remained unconvinced, their doubts focusing on three points:

1. A small genetic difference can still make a big cultural difference

Even if human populations differ only slightly at certain gene loci, these slight differences can still have big effects.

For instance, the historical economist Gregory Clark has argued that the slow but steady demographic expansion of the English middle class from the 12th century onward gradually raised the population mean for predispositions to non-violence, deferment of pleasure, and other future-oriented behavior. Although the nascent middle class was initially a small minority in medieval England, its descendants grew in number and gradually replaced the lower class through downward mobility. By the 1800s, its lineages accounted for most of the English population.

There then came the triumph of Victorian morality—a relatively sudden cultural change due to a genetic change that had slowly reached a point of critical mass. The English middle class could now impose its behavioral norms on the whole population, thereby abandoning the ‘two-tier morality’ of other class-stratified societies (Clark, 2007, pp. 124-129, 182-183; Clark, 2009).

2. Lewontin’s finding is true only if we look at one gene at a time

Genes vary much more within than between human populations only if we look at one gene at a time. The pattern reverses if we aggregate variation at several gene loci. The more we aggregate, the more the genetic variation will exist between populations and not within them. This point was first made by Cavalli-Sforza back in 1966 and later by Mitton (1977, 1978), Edwards (2003), and Sesardic (2010).

3. A big chunk of inter-individual genetic variation is actually intra-individual

Although only 15% of human genetic variation is composed of population differences, the remaining 85% is not necessarily between individuals. Since we are diploid organisms, some genetic variation is actually intra-individual—the differences between the genes you inherited from your mother and the genes you inherited from your father. If we factor out this kind of variation, population differences actually account for a third of all human genetic variation (Sarich and Miele, 2004).

How valid are these three points?

The first one was true historically and, presumably, prehistorically. A slight genetic advantage could indeed leverage very disproportionate benefits. “Winner takes all.” This kind of dynamic, however, is no longer legitimate in modern societies, at least not to the same extent. Although we accept that losers should lose, we don’t accept that they should lose everything. Our societies provide a wide array of redistributionist mechanisms to ensure that slight advantages don’t snowball into big ones.

The second point is certainly true. Clearly, two groups are easier to tell apart with several criteria than with one. With enough criteria, any overlap will shrink to zero and all individuals can be unambiguously assigned to either group. This is basic logic. But all this proves is that human populations are identifiable. It doesn’t prove that the differences between them are greater than the differences within them.

The third point invites the same reply of “So what?” If our intra-population variation is inflated by intra-individual variation, the same would be true for all species, and not just our own. Remove intra-individual variation, and you’ll certainly get a higher estimate of inter-population variation. But this will be true across the board. Human races will still look relatively unimportant.

In all this, a more fundamental criticism is being ignored. How meaningful is the ratio of inter-population to intra-population variation? Just what exactly does it tell us?

This ratio, called Fst, is not as meaningful as one might think:

Fst isn’t a good measure of genetic-phenotypic mediation. As a case example, Long and Kittles (2003) found a between human population Fst of 11% based on their sample; when they added chimpanzees, the between population Fst increased only to 18% [3]. Mountain and Risch (2004), citing this example, note that ‘‘a low FST estimate implies little about the degree to which genes contribute to between-group differences.’
(Occidentalist, 2011)

Indeed, some sibling species show the same kind of genetic overlap that we see between human races. And yet these species are anatomically, physiologically, and behaviorally distinct (Frost, 2008).

Remember, when two populations differentiate under the impact of diverging selection pressures, this differentiation concerns only a tiny fraction of the genome. Why? There are two reasons:

(a) Much genetic variation is of low selective value, often being little more than "junk" variability, and thus responds weakly to changes in selection pressure.

(b) Much genetic variation is equally adaptive in both of the new adaptive landscapes. There are many cases of genetic polymorphisms that widely occur not only among different populations of one species, but also among related species (Klein et al., 1998).

Fst cannot tell us how much populations really differ from each other within a species—and by ‘really’ we’re talking about adaptive differences that show up in anatomy, physiology, and behavior. It basically tells us how long these populations have been separated from each other, with some adjustment for ongoing gene flow. In our case, Fst tells us that human races are young, very young.

But this we know already. The past 40,000 years have seen our ancestors spread into a multitude of natural environments—from tropical rain forest to arctic tundra. And the past 10,000 years have seen humans enter an even greater variety of cultural and social environments—from simple horticulture to complex societies with class differentiation, State formation, urbanization, systematized religion, and the ability to store, accumulate, and exchange information via writing.

We also know that these same years have seen an accelerating pace of genetic change. Natural selection has altered at least 7% of our genome over the last 40,000 years. In particular, the speed of genetic change rose over a hundred-fold with the advent of agriculture some 10,000 years ago (Hawks et al., 2007).

The correlation is very weak between the passage of time and the degree of evolutionary change. Some organisms have remained virtually the same for millions of years. Others have changed very quickly. We, humans, are the fast runners of evolution.

References

Cavalli-Sforza, L.L. (1966). Population Structure and Human Evolution, Proceedings of the Royal Society of London. Series B, Biological Sciences, 164, 362-379.

Cavalli-Sforza, L.L., P. Menozzi, and A. Piazzi. (1994). The History and Geography of Human Genes, Princeton: Princeton University Press.

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World, Princeton University Press, Princeton and Oxford.

Clark, G. (n.d.). The indicted and the wealthy: surnames, reproductive success, genetic selection and social class in pre-industrial England, http://www.econ.ucdavis.edu/faculty/gclark/Farewell%20to%20Alms/Clark%20-Surnames.pdf

Edwards, A.W.F. (2003). Human genetic diversity: Lewontin’s fallacy. BioEssays, 25, 798-801.

Frost, P. (2008). The 85% truism, Evo and Proud, January 4

Hawks, J., E.T. Wang, G.M. Cochran, H.C. Harpending, and R.K. Moyzis. (2007). Recent acceleration of human adaptive evolution, Proceedings of the National Academy of Sciences USA. 104, 20753-20758.

Jorde, L.B., W.S. Watkins, M.J. Bamshad, M.E. Dixon, C.E. Ricker, M.T. Seielstad, and M. A. Batzer. (2000). The Distribution of Human Genetic Diversity: A Comparison of Mitochondrial, Autosomal, and Y-Chromosome Data, American Journal of Human Genetics, 66, 979–988.

Klein, J., A. Sato, S. Nagl, and C. O’hUigin. (1998). Molecular trans-species polymorphism, Annual Review of Ecology and Systematics, 29, 1-21.

Lewontin, R. (1972). The apportionment of human diversity, Evolutionary Biology, 6, 381-398.

Long, J.C. and R.A. Kittles. (2003). Human Genetic Diversity and the Nonexistence of Biological Races, Human Biology, 81, 777-798.

Mitton, J.B. (1977). Genetic differentiation of races of man as judged by single-locus and multilocus analyses, American Naturalist, 111, 203-212.

Mitton, J.B. (1978). Measurement of differentiation: reply to Lewontin, Powell, and Taylor, American Naturalist, 112, 1142-1144.

Mountain, J.L. and N. Risch. (2004). Assessing genetic contributions to phenotypic differences among ‘racial’and ‘ethnic’groups, Nature Genetics, 36, S48 - S53.

Occidentalist (2011). Did Sarich Get It Right? Occidentalist, April 14
http://occidentalascent.wordpress.com/2011/04/14/did-sarich-get-it-right/

Sarich, V. and F. Miele. (2004). Race: The Reality of Human Differences, Basic Books.

Sesardic, N. (2010). Race: a social destruction of a biological concept, Biology and Philosophy, 25, 143-162.

Is teen motherhood pathological?

2011-04-15T13:39:00.009-05:00

Figurine of African American grandmother and child.

Is teenage childbearing pathological? Anthropologist Linda Burton argues otherwise in her study of an African American community, and she cites other researchers who have come to similar conclusions:

Hamburg (1986) suggests that teenage childbearing, within certain poor black subgroups, reflects an alternative life-course strategy rather than a nonnormative life event. […] Furthermore, the long-term outcomes of teenage childbearing in these subcultures are not necessarily as devastating as mainstream impressions imply (Furstenberg et al. 1987). Rather, early childbearing may be perceived as a viable option that fosters individual growth, family continuity, and cultural survival in an environment in which few other avenues for enhancing development are available. (Burton, 1990, p. 124)

By viewing teenage childbearing as a reproductive strategy, with its own logic and life goals, we may better understand why it happens and know how to prevent it. Viewing it as a pathology has simply given us “solutions” that don’t work … and endless rationalizations for their failure to work.

Among African Americans, this reproductive strategy has one key characteristic: an accelerated family timetable. All life stages begin and end earlier:

Childhood: 1 to 10 years of age

Adolescence: 11 to 13

Motherhood: 14 to 26

Grandmotherhood: 35 to 45

Great grandmotherhood: 56 to 68

There is also separation of reproduction from marriage. Parenting is provided by the child’s mother and maternal grandmother. The father is usually absent. Households tend to be multigenerational with much exchange of services between younger and older generations and between siblings.

[…] given the fact that teenage childbearing families have more children per generation, it is likely that they have a broader array of potential caregivers, including older children who can assist in the care of their younger siblings, young adults who can help older family members, and young grandmothers who can parent the infants of teen mothers (Burton, 1990, p. 128)

Burton found that some African American women “covertly and sometimes overtly encouraged their teenage daughters to bear a child.” They wished to have the experience of rearing children—an experience denied them when they themselves had to rely on their maternal grandmothers many years earlier.

Once the maternal grandmother becomes a primary caregiver, the cycle of early motherhood tends to self-perpetuate. This is suggested by comments to Burton from a 35-year-old potential grandmother:

I suspect that my daughter (14 years old) will have a baby soon. If she doesn't I'll be too old to be a grandmother and to do the things I'm supposed to do, like raise my grandchild. (Burton, 1990, p. 132)

Similarly, a 58-year-old great-grandmother told Burton:

The best way to make sure that you have enough able bodies to take care of the needs in the family is to start the women having children as soon as they can. (Burton, 1990, p. 133)

Similarities and dissimilarities with the African marriage system

So far, most of the above sounds like the African system of mating and reproduction, as discussed in the last two posts. Unlike sub-Saharan Africa, however, polygyny is not institutionalized. Instead of being secondary sources of childcare, men are typically absent altogether:

In contrast to the duties of females, the role responsibilities of males in the family are ambiguous. Both the male and female respondents indicated that few familial duties are assigned to males. As young children, boys could assist girls with household tasks. Once male children reach later childhood, however, their energies are invested outside the home. Beginning at about age 10, the socialization of boys is primarily in the hands of peers and older men in the community who instruct them in the ways of survival in Gospel Hill. These instructions focus on job opportunities for black men, male/female relationships, and sexual behavior. (Burton, 1990, p. 135)

As in sub-Saharan Africa, the mother identifies first and foremost with her own kin. Unlike sub-Saharan Africa, however, she isn’t just less attached to the father. She is estranged from him, and this estrangement borders on hostility if the father consorts with white women. The following comment is from a 14-year-old mother:

Ever since I can remember I always expected to have a baby when I was 15 or 16 but I never believed I would ever have a chance to get a husband. One of the things my grandmother always said, "Pay your dues to your kin because they will take care of you. There ain't no reason to waste your time on a colored man because they don't want us no way." (Burton, 1990, p. 133)

Curiously, while citing Patricia Draper’s study on African marriage systems, Linda Burton attributes this polygyny and low paternal investment to factors that are specific to the United States. Hence, racism and the shift from manufacturing to services is said to prevent African American men from getting good jobs and becoming active fathers (Burton, 1990, p. 127).

Future of teenage childbearing among African Americans

While teenage childbearing can provide effective means of family formation, often more effective than later childbearing, it is not without its weaknesses. One of them is the willingness of maternal grandmothers to become primary caregivers. Personal autonomy is becoming a supreme value in all age groups of American society, including middle-aged and older women:

The majority of young grandmothers studied refused to assume the primary role in rearing their grandchildren. These grandmothers felt that being a surrogate parent for their grandchild did not fit with their current lifecourse activities--that included a variety of "young-adult" roles involving work, education, friendships, romance, and even their own continued childbearing. (Burton, 1990, p. 128)

Easier birth control, especially abortion, is also having an impact. Even when women wish to have children early in life, they still tend to postpone this kind of momentous decision—if given the choice.

African American fertility is now 2.2 children per woman, i.e., replacement level. And this rate is being buoyed up by a very fertile subculture of teen mothers. Most African Americans have, in fact, entered the zone of below-replacement fertility.

Conclusion

This teen mother subculture displays many elements of the African marriage system (polygyny, low paternal investment, high value placed on childbearing, strong ties with maternal kin). These elements, however, have to operate within Euro-American legal and cultural constraints, which are modeled on the marital norms of Eurasia in general and Western Europe in particular (long-term monogamy, high paternal investment, voluntary limitation of family size, relatively weak ties with kin beyond the nuclear family).

These constraints meet with varying degrees of compliance among African Americans. At one end of the continuum are those who fully comply. At the other are those who comply as little as possible, i.e., the teen mother subculture. The middle encompasses those who comply more or less.

Certain factions, notably the Black Muslims, have sought to create a new set of constraints that would be more in line with the African marriage system. But such efforts have largely failed. For the near future, at least, the teen mother subculture will become increasingly problematic, particularly as more and more older women refuse the obligations of grandmotherhood. The African American community as a whole will thus continue its slide into below-replacement fertility.

References

Burton, L.M. (1990). Teenage childbearing as an alternative life-course strategy in multigeneration black families, Human Nature, 1, 123-143.

Draper, P. (1989). African marriage systems: Perspectives from evolutionary ecology, Ethology and Sociobiology, 10, 145–169. http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1007&context=anthropologyfacpub

The African outlier

2011-04-08T16:01:00.008-05:00

While birth rates fall everywhere else, sub-Saharan Africa remains an outlier of high fertility (2009).

Throughout most of the world, the demographic transition has played out as predicted. Fertility rates have fallen to replacement level and even lower, first in Europe and North America and more recently in East Asia, Southeast Asia, the Middle East and North Africa. The exceptions are societies where religious fundamentalists exert a strong influence on childbearing: Mormons and Amish in the United States, and Islamists in Saudi Arabia, Afghanistan, and Pakistan.

There is, however, an area where the demographic transition seems permanently stalled for reasons unrelated to religion. That area is sub-Saharan Africa. How come?

This puzzle caught the attention of anthropologist Patricia Draper back in the late 1980s. Sub-Saharan Africa had become an outlier of high fertility, even after adjustment for those factors that were lowering birth rates elsewhere. This excess fertility seemed to be due to a different social environment for mating and reproduction:

[…] in much of Africa, not only among country people but among urban populations as well, there persists high fertility and a pattern of parental investment in which both mothers and fathers invest, by Western standards, relatively little in each offspring and pursue a pattern of delegated parental responsibility (Draper and Harpending 1988). Coupled with low investment parenting is a mating pattern that permits early sexual activity, loose economic and emotional ties between spouses (Potash 1978), and in many cases the expectation on the part of both spouses that the marriage will end in divorce or separation, followed by the formation of another union (Aldous 1962; Lowy 1977; Oppong 1974; Mair 1953; Gibson 1958; Hunter 1961; Tuupainen 1970). Polygyny, still widespread in Africa, inhibits high male parental investment in children […] (Draper, 1989, p. 145-146)

In sub-Saharan Africa, parenting is assumed primarily by the mother and her kin. The parents, especially the father, are thus under much less pressure to limit family size. As Draper notes :

[…] people do not scale down expectations for large numbers of children precisely because their understandings about available resources take into account reservoirs of surrogate care among their kin. […] African men may see no urgency in reducing the numbers of their progeny precisely because a characteristically African set of socioecological circumstances permit many children to survive despite low father contribution to child support. (Draper, 1989, p. 147)

This is in contrast to the situation of parents elsewhere, particularly in modern urban settings, where a larger family perceptibly reduces the resources left over for the parents.

Will things change in the near future? Much depends on whether African families adopt the Eurasian marriage system, i.e., monogamy, long-lasting marital bonds, and high parental investment in children (including high paternal investment). To date, despite the efforts of missionaries and government authorities, there has been little change in this direction.

African men, in particular, are reluctant to assume a more active parental role:

Much of rural African subsistence is based on the work of women in their gardens; men make only modest contributions. Typically, rights in land are held by men by virtue of their membership in kinship or village units. A man who wishes to add another wife is under few constraints (provided his kinship group has the land and bridewealth), since women, in effect, pay their own way. They produce food, and they rear children. In rural areas, when a man marries an additional wife, he is awarded additional fields for this woman and her children (Bryson 1981). The importance of male labor to support such households is reduced. In former times, before colonially imposed peace, the male role in defense was important. But since central governments have been present, men who remain in rural villages spend their time in leisure, in management of household labor, or in local political affairs (Potash 1978). More recently, men absent themselves for long periods in migratory labor. They send remittances home that help to pay school and medical fees and to buy clothing. Nevertheless, the work of feeding people remains with women (Hafkin and Bay 1976; Vaughan 1983).

[…] Many efforts have been made to induce African men to increase their agricultural labor. The more successful of such ventures have followed the introduction of cash crops and the development of markets. Men are more willing to work at raising cash rather than traditional subsistence crops. However, since most cash crops are not food crops, women continue to do the subsistence farming, for which cash conversion is less possible, and they work even harder, since the men are busy with cash crops and have even less time for periodic help in the family gardens at clearing and harvest time (Obbo 1980; Whiting 1977; Kelley 1981). Characteristically, men do not return their earnings from cash crops to the household economy. This money is held separately and spent by men on their own projects (Vellenga 1983; Abu 1983; Bryson 1981). (Draper, 1989, p. 152)

As Africans migrate to other parts of the world, they tend to recreate the African marriage system in their host countries by using local people and institutions as “surrogate kin” Draper describes the situation in England, where young African couples often place their children in foster homes:

As might be expected, the outcome for all concerned does not work in the way it is expected to in West Africa. The foster parents interpret the infrequent visiting of their wards’ “real” parents as signs of parental neglect and become strongly attached to the foster children. This sometimes results in legal suits for transfer of custody to the foster parents (Ellis 1977). Meanwhile, the African parents make no comparable assumption that the delegation of care means they have surrendered formal rights in children. They consider that by having made safe and reliable arrangements for the care of children and by regular payment of fees, they are dispatching their immediate responsibility. (Draper, 1989, p. 164)

Ironically, when infertile Western couples go to Africa to adopt, as is increasingly the case, the adopted child evokes a degree of parental attachment that it would not normally evoke from its natural parents—even in the best of circumstances.

Reference

Draper, P. (1989). African marriage systems: Perspectives from evolutionary ecology, Ethology and Sociobiology, 10, 145–169.

http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1007&context=anthropologyfacpub

Are African women oppressed?

2011-04-01T14:19:00.016-05:00

Guess who does the farmwork? In sub-Saharan Africa, women do most of the labor. On the other hand, they have more control over the fruits of their labor.

Are African women oppressed? For many, the answer is ‘yes’:

Much popular writing and many popular ideas about gender in Africa continue to rest on the belief that women in all societies in the entire world are oppressed and that African women are particularly oppressed. Even in scholarly studies, the assumption of universal male dominance of African social and economic relations persists. (Saidi, 2010, p. 12)

It’s true that women do most of the labor in sub-Saharan Africa. They are, in fact, largely self-reliant in providing for themselves and their children:

In sub-Saharan Africa, the labor of women was usually the work of daily subsistence. […] Hunting and warfare, usually the activities of men, could in contrast produce either a big windfall or nothing at all in terms of male production. […] Therefore, in a very simplistic way, it can be argued that female labor was the necessary labor—the labor from which surplus could be derived—whereas male labor could produce the luxury items, the status items. (Saidi, 2010, p. 15)

This argument ignores, however, the greater power of African women over the fruits of their labor. Often, this power was totally in the hands of women, typically older matriarchs:

The labor of young women, and young men, for that matter, in many East-Central African societies, particularly among the Sabi-speaking group of peoples, was historically controlled by the older female matrilineal kin of the young women, not by men at all. (Saidi, 2010, p. 16)

Indeed, one could argue that African men tended to occupy a peripheral role within the family:

Poewe found in her fieldwork that the marriage institution was highly flexible and discouraged strong, intense, or lasting solidarity between husband and wife. The male in these matrilineal societies did not produce for his progeny or for himself, but usually for a matriclan with whom he might or might not reside. His role, as husband, was to sexually satisfy and impregnate his wife and to take care of her during her pregnancies, but under no circumstances should a man be the object of “exclusive emotional investment or focus of attention. Instead, women are socialized to invest their emotions and material wealth in their respective matrilineages.” (Saidi, 2010, p. 16).

This situation has changed since the colonial era, largely under the impact of Christianity and Islam. Efforts have been made to restructure the African family, specifically to make the marriage bond monogamous, exclusive, and longer-lasting and to increase paternal investment in offspring.

Interestingly, there is evidence that this trend actually began some two centuries before the colonial era. Previously, the African family had been even more matrilineal, matrilocal, and matriarchal:

Murdock proves beyond reasonable doubt that the most ancient form of unilineal descent among the Niger-Congo, and therefore among the Bantu-speaking peoples (whose languages belong to the Niger-Congo family), was matriliny. He specifically reconstructs this feature for the proto-Bantu. He demonstrates it through his mapping of the scattered, relict preservation of matriliny all across the Niger-Congo-speaking regions, even in the Kordofanian branch of the Niger-Congo languages, which is spoken far away from the rest of the family in Sudan.

[…] The oral traditions of the Kanyok, who belong to the Central Savanna Bantu subgroup, still remember their shift from matrilineal to patrilineal descent a number of centuries ago, as John Yoder reveals. Most telling of all, the founders of the clans of the Gikuyu of Kenya are female, even though today the Gikuyu are strongly patrilineal. By definition, matrilineal clans must have female founders; therefore, this is undisputed evidence for prior matriliny among the Bantu-speaking peoples of the eastern Kenya highlands.

[…] The historical priority of matriliny among the Niger-Congo peoples in general—as well as among peoples speaking languages of the Bantu subgroup of Niger-Congo—is extensively and convincingly demonstrated by the comparative ethnographic evidence. Recent work in linguistic reconstruction directly supports the view that the early Bantu communities, who established themselves successively more widely in the rainforest and then in the southern savannas and eastern Africa during the last three thousand years BCE, observed unilineal descent in the form of matrilineages and/or matriclans. (Saidi, 2010, pp. 13-14)

According to Saidi (2010, pp. 12-19), sub-Saharan Africa saw a relative shift of power from women to men from around 1500 onward—apparently as a result of warfare induced by the slave trade. On the one hand, war enhanced the prestige of men through the plundered wealth they brought to their communities. On the other, women looked to men for protection during times of war.

Was there previously, then, a golden age of non-oppression? And are African women now oppressed? In truth, words like ‘oppression’ are easily abused in a context where the goal of life is not self-maximization. Yes, African women produce far beyond their own needs, but the economic surplus goes primarily to their children. If anyone is getting something for nothing, it is surely the children.

But that’s not how Africans themselves see it—or for that matter humans in any traditional society. Children are literally seen as the ‘after-life.’ It’s not out of masochism that African mothers make sacrifices for them. It’s out of a profound belief that “no one gets out of here alive”—other than one’s children and their descendents.

Reference

Saidi, C. (2010). Women’s Authority and Society in Early East-Central Africa, University of Rochester Press.