John Tooby and Leda Cosmides. Why not collaborate?

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. Thus, both social scientists and natural scientists have been enlisted in what has become a common enterprise: the resurrection of a barely disguised and archaic physical/mental, matter/spirit, nature/human dualism, in place of an integrated scientific monism. (Barkow, Cosmides, & Tooby, 1992)

In writing the above words, the evolutionary psychologists John Tooby and Leda Cosmides were denouncing an unwritten agreement that had let researchers study everything about our species in biological terms … except the human mind. Concretely, this modus vivendi denied ‘safe conduct’ to those who wanted to investigate genetic influences on the way the mind develops and functions, unless the creature in question was nonhuman.

While attacking these constraints on research, Tooby and Cosmides actually paved the way for a new set of constraints. Academics would be free to study genetic influences on the mind, as long as these influences did not differ from one human population to another. The two evolutionary psychologists saw no problem in this because, in their opinion, there were no population differences to study.

They justified this opinion on two grounds. First, the more complex the adaptation, the more genes it involves, and the more time needed to make all of the right changes to all of the right genes. Therefore, evolution has created only simple traits during the relatively recent presence of modern humans outside Africa (< 50,000 years):

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.

… For these and other reasons, the complex architecture of the human psyche can be expected to have assumed approximately modern form during the Pleistocene, in the process of adapting to Pleistocene conditions, and to have undergone only minor modifications since then (Tooby & Cosmides, 1989, p. 34).

There was a second justification for the new modus vivendi. Because the past fifty thousand years have seen our species diversify into a wide range of environments, recent traits would tend to be adaptive in some environments but not in others. And their underlying genetic variants would tend to proliferate in some populations but not in others. Yet such population specificity seems impossible. 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 (1972) concluded that 85% of our genetic variation exists only among individuals and not between ‘races.’

Tooby and Cosmides (1990, p. 35) explicitly referenced Lewontin’s paper when they argued this point:

Human groups do not differ substantially in the types of genes found, but instead only in the relative proportions of those alleles. … What this means is that the average genetic difference between one Peruvian farmer and his neighbor, or one Bornean horticulturist and her best friend, or one Swiss villager and his neighbor, is 12 times greater than the difference between the "average genotype" of the Swiss population and the "average genotype" of the Peruvian population (i.e., the within-group variance is 12 times greater than the between-group variance).

This is true but does not mean what one might think. The same genetic overlap exists not only between populations of one species, like our own, but also between related species, like canids.

[U]sing genetic and biochemical methods, researchers have shown domestic dogs to be virtually identical in many respects to other members of the genus. … there is less mtDNA difference between dogs, wolves and coyotes than there is between the various ethnic groups of human beings, which are recognized as belonging to a single species (Coppinger & Schneider, 1995, p. 32-33).

Nor is it true that genetic influences on behavior evolve over eons of time. As Henry Harpending and Gregory Cochran (2002) pointed out:

Even if 40 or 50 thousand years were too short a time for the evolutionary development of a truly new and highly complex mental adaptation, which is by no means certain, it is certainly long enough for some groups to lose such an adaptation, for some groups to develop a highly exaggerated version of an adaptation, or for changes in the triggers or timing of that adaptation to evolve. That is what we see in domesticated dogs, for example, who have entirely lost certain key behavioral adaptations of wolves such as paternal investment. Other wolf behaviors have been exaggerated or distorted.

The above points are so elementary that it’s a wonder they never crossed the mind of either John Tooby or Leda Cosmides. Or perhaps they did. I remember attending a talk where John Tooby expressed his skepticism about Lewontin’s 1972 paper, saying that within-population genetic variation was inflated by disease polymorphisms and other junk variability. In addition, he had a low opinion of Lewontin, as seen in this exchange in 2000 with Slate editor, Judith Shulevitz:

In the mid-1970's, for example, Gould, Lewontin, and a few others injected heavy-handed moralizing, easy denunciation, the attribution of dubious intellectual genealogies, and an ad hominem attack-style into scientific debate in an effort to settle intellectual disputes by other means.

… The most notorious tactic of Gould, Lewontin, and their allies during the early years was their attempt to drag the ideas they opposed under by manufacturing links to various repugnant doctrines. … More significantly, they did succeed in tarring the revolution in evolutionary biology in the eyes of nonbiologists, together with any serious attempt to think through the relationship between culture, human nature, and human evolution. This has perpetuated the antiquated status quo, during which social scientists have remained wary of the possibility of scientifically mapping human nature, and have remained almost totally ignorant of modern evolutionary biology. The cumulative harvest of suffering from this will not be small.

Why, then, did Tooby and Cosmides accept Lewontin’s findings so uncritically? Or was this acceptance simply window-dressing, an attempt to procure ‘safe conduct’ for their research?

Such a question has no easy answer. By the late 1970s, few academics wished to discuss whether or not human races exist, any more than people of another age wished to discuss whether or not Jesus had a biological father. There was only one acceptable view. The new academic environment thus allowed a lot of dubious ideas on this subject to go unchallenged because challenging them might lead to accusations of racism. Academics became used to having two sets of beliefs: those they really believed and those they believed for convenience sake. Over time, many lost the ability to distinguish between the two.

Well, so Tooby and Cosmides fudged their beliefs a bit. Wasn’t it worth it? Hasn’t the academic environment become much less hostile to research on “the relationship between culture, human nature, and human evolution”?

The answer to the last question is ‘yes’. It’s less clear, however, whether Tooby and Cosmides had anything to do with the improved academic environment. The last quarter of a century has seen broader societal changes that are probably more relevant.

One was the decline of the far left. In the early 1980s, every college in my city had a Marxist-Leninist club. By the end of the decade, they had all disappeared. Marxists had become few and far between even at the university.

A related factor was the aging of the baby-boomer generation. In the early 1980s, every social science department was flush with young people who often had no idea why they were there. By the end of the decade, the baby boomers were gone and enrolment in the social sciences had fallen by over a half. Students also now tended to be more cynical about politics and more narrowly focused on their studies.

Finally, in the mid-1990s, there was the rise of the Internet. It became possible to discuss ideas outside the normal channels of conferences, peer-reviewed journals, and university publishing houses. This freer academic environment gradually replaced the one that had arisen back in the mid-1970s when ideas flowed through fewer channels and were more easily controlled.

I suspect that Tooby and Cosmides deceived themselves in thinking they could obtain a ‘safe conduct’ for their research from the likes of Lewontin and Gould. The only real-world effect of this self-deception has been to make evolutionary psychology subservient to ideas that are, at best, dubious.

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.

Coppinger, R., & R. Schneider, Evolution of working dogs, in: J. Serpell (Ed.), The Domestic Dog: Its Evolution, Behaviour and Interactions with People, Cambridge University Press, Cambridge, 1995, pp. 21-47.

Harpending, H. & G. Cochran. (2002). In our genes, Proceedings of the National Academy of Sciences USA, 99(1), 10-12.

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

Tooby, T. & L. Cosmides. (1990). On the universality of human nature and the uniqueness of the individual: the role of genetics and adaptation, Journal of Personality, 58, 17-67.

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

Claude Lévi-Strauss. The refusal to collaborate

French anthropologist Claude Lévi-Strauss is remembered as one of the leading postwar figures of antiracism. He personally encountered racism in 1940 when his Jewish origins cost him his teaching post. As an anthropologist in Brazil, he saw first-hand the dispossession of native peoples in the name of progress. In a UNESCO booklet, Race and History (1952), he pleaded for the preservation of all human cultures, saying that even the most ‘primitive’ ones deserved to survive.

This is the Lévi-Strauss we remember. There was, however, a later stage in his intellectual development that remains largely unknown to most of us, if only because little came of it.

We can see hints of these later views in his 1952 publication, which shows him already deviating from the postwar antiracist consensus:

There are [cultural] contributions that are systemic in character, i.e., corresponding to the specific way each society has chosen to express and satisfy human aspirations as a whole. These ways of life are undeniably original and irreplaceable, but since they represent so many different choices that are exclusive [to each society] it is hard to see how a civilization could benefit from another one’s way of life, unless it renounced being itself.

By the early 1970s, he had become convinced that the emerging world system would eventually liquidate all cultures, and not simply those of the upper Amazon. He also felt that antiracism was moving away from its role of defending the dispossessed and the politically marginalized. In fact, it was becoming the very thing it used to denounce.

These ideas found their way into a lecture he gave to UNESCO in 1971, ironically to launch the International Year for Action to Combat Racism. In this lecture, he attacked the idea that “the spread of knowledge and the development of communication among human beings will some day let them live in harmony, accepting and respecting their diversity ”:

Nothing indicates that race prejudices are decreasing, and everything suggests that after brief local lulls, they resurge elsewhere with increased intensity. Hence the need felt by UNESCO to periodically restart a fight whose outcome seems at the very least uncertain.

But are we so sure that the racial form of intolerance results primarily from false ideas that such or such a population has about the dependence of cultural evolution on biological evolution? Don’t these ideas simply provide an ideological cover for more real conflicts based on the desire to subordinate and on the relative strengths of competing groups (rapports de force)?

In addition, he argued that cultural intermixture is advantageous only if a certain distance is kept between cultures:

[Humanity] will have to relearn that all true creation implies some deafness to the call of other values, which may reach the point of rejecting or even negating them. One cannot at the same time melt away in the enjoyment of the Other, identify oneself with the Other, and keep oneself different. If fully successful, complete communication with the Other will doom its creative originality and my own in more or less short time. The great creative ages were those when communication had increased to the point that distant partners stimulated each other but not so often and rapidly that the indispensable obstacles between individuals, and likewise between groups, dwindled to the point that excessively easy exchanges would equalize and blend away their diversity.

He also maintained that many cultural differences have, over time, produced biological differences:

We cannot insist too much on one fact: although [natural] selection has allowed living species to adapt to the natural environment or to better resist its transformations, with humans the environment has ceased to be primarily natural. Humans derive their distinctive characteristics from technical, economic, social, and mental conditions that, through the operation of culture, create an environment specific to each human group.

… Among early humans, biological evolution may have selected for pre-cultural traits like capability to stand upright, manual dexterity, sociability, symbolic thinking, and ability to vocalize and communicate. It was culture, however, once it came into being, that consolidated these traits and propagated them. When cultures specialize, they consolidate and favor other traits, like resistance to cold or heat for societies that have willingly or unwillingly had to adapt to extreme climates, like dispositions to aggressiveness or contemplation, like technical ingenuity, and so on. In the form these traits appear to us on the cultural level, none can be clearly linked to a genetic basis, but we cannot exclude that they are sometimes linked partially and distantly via intermediate linkages. In this case, it would be true to say that each culture selects for genetic aptitudes that, via a feedback loop, influence the culture that had initially helped to strengthen them.

His lecture ended on a grim note. The population explosion, combined with competition for increasingly scarce resources, will push diverse populations together under conditions less than optimal for peaceful coexistence. Meanwhile, governments will continue to respond with an “ideological struggle against racism”, in the naïve belief that the rising level of tension is being caused by a rising level of ignorance.

… the path that mankind is going down is building up tensions such that racial hatreds provide a pretty poor picture of the regime of heightened intolerance that may become established tomorrow, without even having ethnic differences to serve as a pretext. To circumvent these perils, those of today and those, ever more redoubtable, in the near future, we must persuade ourselves that their causes are much deeper-rooted than those causes that may simply be put down to ignorance and prejudice. We can place our hope only in a change in the course of history, which is much harder to bring about than progress in the course of ideas.

He pursued this line of reasoning during the discussions that followed, as this account makes clear:

Lévi-Strauss felt that UNESCO was going astray by wanting to reconcile two opposed tendencies: civilising progress leads to growth in populations, which encourages cultural exchanges, but the latter lead to the obliteration of cultural diversity, while at the same time demographic saturation causes its inevitable share of intolerance and hostility towards peoples that have become rivals. In this situation, Lévi-Strauss came to maintain the right of every culture to remain deaf to the values of the Other, or even to contest them. This amounted to replacing the conception – defended by UNESCO – of humans spontaneously open to the Other and brought to cooperate with their fellow humans, by a conception of humans naturally inclined to be if not hostile, then at least reserved towards the Other.

Xenophobia – in the very moderate form that Lévi-Strauss gave to it, that of insensitivity to the values of the Other – is here transformed from a fact of modifiable culture into a fact of ineradicable nature. As a result, for Lévi-Strauss the UNESCO project became partially ineffectual, as one cannot hope to change unalterable human nature by action taken on its social element, through education and the fight against prejudice.

These words shocked the listeners. One can easily imagine how disconcerted UNESCO employees were, who, meeting Lévi-Strauss in the corridor after the lecture, expressed their disappointment at hearing the institutional articles of faith to which they thought they had the merit of adhering called into question. René Maheu, the Director General of UNESCO, who had invited Lévi-Strauss to give this lecture, seemed upset. (Stoczkowski, 2008)

Eight years later, Lévi-Strauss recalled this event at another conference. He spoke even more candidly this time, calling antiracism a “trap”:

I believe we have fallen into traps. I remember, if you will let me inject a personal note into this debate, that in 1952 I produced at UNESCO’s request a small booklet called Race and History in which I exalted collaboration between cultures, and in which I showed that it was only to the extent that cultures collaborated with each other willingly or unwillingly that larger, more solid ensembles would arise.

When UNESCO organized in 1971 the year against racism, I was asked to deliver the opening speech. So I said to myself: “No, all the same it’s not possible. We can’t go on year after year repeating nice sentiments and telling ourselves we’re going to further the progress of humanity this way.” And so instead of doing the same thing, like what I had done in 1952, I decided, and I assure you with no ulterior political motive, that I was going to do the opposite. I was going to show that the problems of nature and nurture were, after all, problems that existed, that it was not absolutely forbidden to look into them, and that it was not by affirming in the most sterile way that there were no differences between human groups and individuals that we would further the progress of humanity.

I need not tell you that this set off a huge scandal but I had no feeling of doing anything different from what I had done nearly twenty years before. I wanted to show that we were facing difficult problems and that for me to stick my head in the sand and refuse to look at them was no way to solve them (Lévi-Strauss, 1985, pp. 43-44)

Lévi-Strauss stressed the need for a new paradigm. Through it, we would be better able to examine the reality of human differences and thus be better positioned to face the oncoming “difficult problems.” As his other remarks at the conference make clear, he believed it would be developed by British and American evolutionary biologists, particularly those associated with the nascent field of sociobiology. In line with his 1971 lecture, he spelled out the form of this new paradigm: gene-culture co-evolution.

But it was not to be. I suspect he had been taken in by the sociobiology-bashing of the late 1970s. In reality, very few sociobiologists were interested in the subject, and most studiously avoided it. This avoidance became an article of faith for John Tooby and Leda Cosmides, who would form the vanguard of this field of study. They considered “implausible the notion that different humans have fundamentally different and competing cognitive programs” (Tooby & Cosmides, 1990, p. 30). After all, Richard Lewontin had proven that human racial variation was nonexistent, or almost so:

Human groups do not differ substantially in the types of genes found, but instead only in the relative proportions of those alleles. … What this means is that the average genetic difference between one Peruvian farmer and his neighbor, or one Bornean horticulturist and her best friend, or one Swiss villager and his neighbor, is 12 times greater than the difference between the "average genotype" of the Swiss population and the "average genotype" of the Peruvian population (i.e., the within-group variance is 12 times greater than the between-group variance) (Tooby & Cosmides, 1990, p. 35).

Ironically, Tooby and Cosmides were skeptical about Lewontin’s findings. I remember attending a talk where John Tooby argued that genetic variation within human groups was greatly inflated by disease polymorphisms and other junk variability. But none of this left a paper trail, probably because that was how they wanted it. They dreamed of getting tenure-track positions and didn’t want trouble. In any case, they had no idea that people like Lévi-Strauss were willing to step forward and take the flak with them.

Eventually, in the late 1990s, a small group of anthropologists began to propound something similar to what Lévi-Strauss had predicted. The term ‘race realism’ was bandied about and it seems to have stuck.

But by then Lévi-Strauss could do little to help. He was nearing his 90th birthday and needed assistance just to go to the bathroom.

References

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.

Lévi-Strauss, C. (1996). Race, histoire et culture, http://www.unesco.org/courier/2001_12/fr/droits2.htm

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

Stoczkowski, W. (2008). Claude Lévi-Strauss and UNESCO, The UNESCO Courrier, no. 5, pp. 5-8.
http://portal.unesco.org/en/ev.php-URL_ID=41820&URL_DO=DO_TOPIC&URL_SECTION=201.html

Tooby, T. & L. Cosmides. (1990). On the universality of human nature and the uniqueness of the individual: the role of genetics and adaptation, Journal of Personality, 58, 17-67.

Richard Dawkins. The price of collaboration?

One of my readers asks whether the renowned evolutionist Richard Dawkins has ever written on the subject of human races. Do they exist? And, if so, did this process of biological diversification stop a long time ago? Or did it actually accelerate when cultural evolution began to accelerate some ten thousand years ago?

Yes, he did address this subject six years ago in the essay “Race and Creation” (Dawkins, 2004). The essay starts off by acknowledging Richard Lewontin’s finding that human genes vary much more within races than between them. In fact, ‘races’ account for only 6 to 15% of all human genetic variation.

Yet this leads to an apparent paradox. According to Lewontin, the data tell us that any two human groups will overlap genetically to a high degree. Our eyes, however, tell a different story:

Well, suppose we took full-face photographs of 20 randomly chosen natives of each of the following countries: Japan, Uganda, Iceland, Sri Lanka, Papua New Guinea and Egypt. If we presented 120 people with all 120 photographs, my guess is that every single one of them would achieve 100 per cent success in sorting them into six different categories.

This paradox has been noticed by others. I remember one who claimed that ‘racism’ prevented us from seeing the genetic overlap between Danes and Congolese. Actually, the same overlap exists between many species that are nonetheless anatomically and behaviorally distinct (see previous post). It isn’t racism that creates the discrepancy between the data and our lying eyes. It’s just that most genes are weakly influenced by natural selection, especially the ‘structural genes’ that Lewontin and other population geneticists love to study. Such genes tell us very little about the strong selection pressures that have sculpted human differences in anatomy and many other traits.

It is fallacious to assume, as Lewontin did, that all genes contribute equally to real functional differences between populations, whether species or races. In fact, most genes have little selective value, being often little more than ‘junk DNA’. Even when a gene clearly is functionally significant, the difference between one allele and another may be like that between Coke and Pepsi. It is also fallacious to assume that genes with low selective value vary between populations in the same way as genes with high selective value. In fact, the more a gene has selective value, the likelier it will vary across a boundary between two different population, since such boundaries usually coincide with geographical/ecological barriers that separate different adaptive landscapes and, hence, different selection pressures.

Dawkins uses ‘Lewontin’s paradox’ to show that races do exist. But how relevant are they to recent human evolution? Hasn’t cultural evolution replaced genetic evolution in our species? On this point, Dawkins argues that the former has actually stimulated the latter. He draws an analogy with sympatric speciation in insects:

Some people think the initial separation has to be geographical, while others, especially entomologists, emphasise so-called sympatric speciation, meaning that the initial separation, whatever it is, is not geographical. Many herbivorous insects eat only one species of plant. They meet their mates and lay their eggs on the preferred plants. Their larvae then apparently “imprint” on the plant that they grow up eating, and they choose, when adult, the same species of plant to lay their own eggs.

… In the case of these insects, you can see that, in a single generation, gene flow with the parental type could be abruptly cut off. A new species is theoretically free to come into being without the need for geographical isolation. Or, another way of putting it, the difference between two kinds of food plant is, for these insects, equivalent to a mountain range or a river for other animals. I am suggesting that human culture—with its tendency to distinguish between in-groups and out-groups—also provides a special way in which gene flow can find itself blocked, which is somewhat analogous to the insect scenario I have just outlined above.

In the insect case, plant preferences are handed down from parent to offspring by the twin circumstances of larvae fixating on their food plant, and adults mating and laying eggs on the same food plants. In effect, lineages establish “traditions” that travel longitudinally down generations. Human traditions are similar, if more elaborate. Examples are languages, religions and social manners or conventions. Children usually adopt the language and the religion of their parents although, just as with the insects and the food plants, there are enough “mistakes” to make life interesting. Again, as with the insects mating in the vicinity of their preferred food plants, people tend to mate with others speaking the same language and praying to the same gods. So different languages and religions can play the role of food plants, or of mountain ranges in traditional geographical speciation. Different languages, religions and social customs can serve as barriers to gene flow. From here, according to the weak form of our theory, random genetic differences simply accumulate on opposite sides of a language or religion barrier, just as they might on opposite sides of a mountain range. Subsequently, according to the strong version of the theory, the genetic differences that build up are reinforced as people use conspicuous differences in appearance as additional labels of discrimination in mate choice, supplementing the cultural barriers that provided the original separation.

At this point, Dawkins winds up his essay, arguing that cultural differences in mate choice may explain many anatomical differences among human populations.

Fine. One point, though. Is mate choice the only human behavior that differs culturally? No, there are also differences in “languages, religions and social manners or conventions.” Wouldn’t these other differences generate selection pressures that likewise differ from one population to the next? And wouldn’t these selection pressures influence not only anatomy but also any trait with a substantial genetic component, including a wide range of behavioral predispositions, mental aptitudes, and personality factors? This would all follow logically from Dawkins’ reasoning. Indeed, he seems to hint at this when he states that “traditions” are no less part of our adaptive landscape than food plants. Having dropped the hint, he goes no further. End of essay.

It’s not as if I’m alone in making the above point. Claude Lévi-Strauss—hardly a rabid sociobiologist—brought it up in a lecture he gave in 1979:

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)

But Lévi-Strauss was never afraid to spell out what he thought. He was a public intellectual in the true sense of the word. In contrast, Richard Dawkins just hints, and hints, and hints … in the hope that someone else will pick up the ball and run with it.

Pathetic.

References

Dawkins, R. (2004). Race and Creation, Prospect Magazine (103), Oct. 23, 2004

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.

Cavalli-Sforza - The price of collaboration?

In a previous post, I noted certain discrepancies between Luca Cavalli-Sforza’s current stand on the race concept and his earlier one. This reversal seems to have occurred between his 1976 book Genetics, Evolution, and Man and his 1994 opus The History and Geography of Human Genes (whose cover map is curiously at odds with his statement that human genetic variation does not cluster into racial groups).

Such a change of heart is all the more puzzling because the case against the race concept had already been made in 1972, when Richard Lewontin showed that genetic differences within human races greatly exceed genetic differences between human races. That was—and still is—the main argument for race denialism. If this argument failed to convince Cavalli-Sforza in 1976, what happened to make it more convincing in 1994?

This is all the more puzzling because several authors since 1972 have challenged Lewontin’s argument. Mitton (1977) and (1978) showed that within-race variation exceeds between-race variation only if one gene is examined at a time. The pattern reverses if several genes are examined at the same time. Another flaw in Lewontin's argument is that he used genetic data from genes that code for enzymes, blood groups, and various building blocks of human tissue. Yet these ‘structural’ genes appear to have been marginal to human evolutionary change. As Stephen J. Gould (1977, p. 406) noted:

The most important event in evolutionary biology during the past decade has been the development of electrophoretic techniques for the routine measurement of genetic variation in natural populations. Yet this imposing edifice of new data and interpretation rests upon the shaky foundation of its concentration on structural genes alone. (faute de mieux, to be sure; it is notoriously difficult to measure differences in genes that vary only in the timing and amount of their products in ontogeny, while genes that code for stable proteins are easily assessed).

Indeed, if we look at differences in structural genes we see a high degree of overlap not only between human populations but also between morphologically distinct species (see previous post).

So why did Cavalli-Sforza change his mind? A cynical answer was provided to me by one anthropologist: “I don't think our perception of the general patterns of genetic variation changed much from '76 to '94, but the intellectual climate that geneticists operate in sure did.”

Some light has been shed on this question by Sesardic (2010). Aside from being an excellent rebuttal of race denialism, this paper also quotes an unpublished manuscript by one of Cavalli-Sforza’s collaborators A.W.F. Edwards. The manuscript describes the following episode:

When in the 1960s I started working on the problem of reconstructing the course of human evolution from data on the frequencies of blood-group genes my colleague Luca Cavalli-Sforza and I sometimes unconsciously used the word ‘race’ interchangeably with ‘population’ in our publications. In one popular account, I wrote naturally of ‘the present races of man’. Quite recently I quoted the passage in an Italian publication, so it needed translating. Sensitive to the modern misgivings over the use of the word ‘race’, Cavalli-Sforza suggested I change it to ‘population’. At first I was reluctant to do so on the grounds that quotations should be accurate and not altered to meet contemporary sensibilities. But he pointed out that, as the original author, I was the only person who could possibly object.

References

Bodmer, W.F. & L.L. Cavalli-Sforza. (1976). Genetics, Evolution, and Man. WH Freeman and Company, San Francisco. pp 563-572.

Cavalli-Sforza, L.L., Menozzi, P. & Piazza, A. (1994). The History and Geography of Human Genes. Princeton: Princeton University Press.

Gould, S.J. (1977). Ontogeny and Phylogeny, Belknap Press: Cambridge (Mass.).

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

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, Biol. Philos. early view.

Are empires bad for your health?

Do empires provide a higher standard of living? In theory, this might seem so. Empires allow goods, capital, and labor to circulate within a much larger land area, thus creating economies of scale and matching supply and demand more efficiently. Empires can also build public works—roads, canals, aqueducts, etc.—that are beyond the reach of smaller territorial entities.

This is still the view in much scholarly writing on the Roman Empire. Yet it is inconsistent with what physical anthropologists are discovering through analysis of skeletal remains. The latest of these studies concerns child burials from 3rd to 5th century Roman Dorchester, in southern England. The children show high levels of malnutrition and trauma: 38.5% had cribra orbitalia—a sign of iron or vitamin B12 deficiency; 12.5% had rickets—a sign of vitamin D deficiency; 4.8% had scurvy—a sign of vitamin C deficiency; and 5.4% had broken ribs (Lewis, 2010).

These rates are much higher than those for medieval England and point to a very poor diet. The incidence of rickets is interesting, since we see a similar high prevalence in industrial England (18th – early 20th centuries). The latter rickets epidemic is usually attributed to industrial smog that blocked UVB radiation and thus impaired vitamin-D synthesis in the skin. A likelier culprit is a diet made up almost wholly of bread, whose high content of phytic acid increases vitamin-D requirements by binding to calcium and phosphorus in the body, thus making these elements unusable (Lindeberg, 1997). This is also probably the cause of Roman-era rickets.

Lewis (2010) cites similar findings from other Roman sites:

Many questions remain about what impact the introduction of urban centers and the gradual economic decline at the end of the Roman Empire had on the local population. Some Roman scholars argue that “Romanization” brought about improvements to the health of the people (Mattingly, 2006, p. 323), with the writing of Roman architects such as Vitruvius conjuring up images of planned Roman cities, with marbled surfaces and flowing water, providing extensive facilities for the comfort and health of the inhabitants (Morley, 2005). Diametrically opposed is the argument that urbanization widened the divide between the rich and the poor, with many suffering hardships of poverty, social unrest, and subservience to the conquering population. The city of Rome itself is seen as overcrowded and filthy, with dogs and muggers prowling the streets, whereas the archaeological evidence calls into question the organization of the water supply and levels of sanitation, with latrines discovered near kitchen areas (Laurence, 1997; Morley, 2005). Garnsey (1999) has hypothesized that undernutrition was endemic in the urban communities of the Greco-Roman world …

Although the Roman Empire brought about an increase in economic wealth, much of this increase seems to have been either siphoned off by the elite or consumed by the large standing army. There is very little evidence that the average citizens were better off under imperial rule, and much suggests that they were worse off.

Why? One reason may be ‘diseconomies of scale.’ Empires tend to liquidate smaller communal entities that more efficiently deliver collective goods, such as community policing, high-trust social networks (for exchange of services and sharing of scarce goods), and support for family formation and child care. This is particularly evident in the Roman Empire’s high infantile mortality rate and low birth rate, with the result that natural increase became negative in late imperial times.

These smaller communal entities were liquidated by the tendency of individuals to migrate from one part of the Empire to another, either on their own or through resettlement of legionnaire veterans. This process of liquidation was also assisted by the State itself, which saw private collectivities as sources of conspiracy or rebellion. In fact, only a limited number of non-State associations were allowed, such as guilds, burial clubs, and officially recognized religions. The persecution of Christians was part of this tendency to see smaller collectivities as threats to the Empire.

Many of us, living in countries where for several centuries we have had fair liberty of association, may not realize just how recent such freedom is but realize that a civilization in which states fear their own citizens is one that recognizes its own inhumanity. Thus it cannot surprise us that in Antiquity most noncommercial associations were forbidden: the authorities realized that any social club might be a center for opposition to the régime. (source)

Empires also make life worse for the average person by fostering dependence on long-distance economic relationships that may collapse if one link in the supply chain disappears. When barbarian invasion disrupted grain shipments between North Africa and Italy in the 5th century, urban populations were suddenly without food. In general, empires create relationships between people who have no commitment to each other beyond short-term economic interest. When a crisis happens, these same people will give priority to their kinfolk … thus leaving in the cold any atomized individuals with no kinship networks to fall back on. When the Roman Empire collapsed, the latter were the ones who suffered the most.

References

Lewis, M.E. (2010). Life and death in a civitas capital: metabolic disease and trauma in the children from late Roman Dorchester, Dorset, American Journal of Physical Anthropology, early view.

Lindeberg, S. (1997), Cereal grains, Paleolithic Diet Symposium List, http://www.paleodiet.com/phytic.txt

Predictions for 2010

This year, look for advances in the following areas:

Brain growth genes

Back in 2005, it was found that human populations vary considerably at two genes, ASPM and microcephalin, that control the growth of brain tissue. The finding seemed to be ‘huge’ in its implications. Then, it all fizzled out. No correlation could be found between variation at either gene and differences in mental ability or head circumference (Mekel-Bobrov et al., 2007; Rushton et al., 2007).

A recent study has now shown that ASPM and several other genes (MCPH1, CDK5RAP2, CENPJ) do in fact influence growth of brain tissue, specifically cortical tissue. Moreover, this influence seems to be strongest for the regulatory regions of these genes, i.e., the portions that regulate the behavior of other genes. But why did earlier studies fail to find anything? One reason is that the software at the time was not sophisticated enough to calculate cortical surface area (as opposed to overall brain volume). Another reason is that earlier studies focused on the non-regulatory regions of these genes.

In 2010, we’ll probably see further developments in this area. Stay tuned …

Early modern human genome

Scientists have retrieved mtDNA from a 30,000 year-old hunter-gatherer from Kostenki, Russia. This seems to be part of a trend to study the genome of early modern humans. The challenge now will be to reconstruct not only the mtDNA but also the nuclear DNA—a serious problem because contamination from contemporary human sources cannot easily be ruled out. Significantly, Prof. Paabo has discovered several ways to minimize contamination.

Population differences in vitamin D metabolism

This year will see further evidence that natural selection has caused differences in metabolism among different human populations, including vitamin D metabolism.

For instance, many populations have long been established at latitudes where vitamin-D synthesis is impossible for most of the year. Some of these populations can get vitamin D from dietary sources (e.g., fatty fish) but most cannot. In these circumstances, natural selection seems to have adjusted their metabolism to reduce their vitamin-D requirements. We know that the Inuit have compensated for lower production of vitamin D by converting more of this vitamin to its most active form (Rejnmark et al., 2004). They also seem to absorb calcium more efficiently, perhaps because of a different vitamin-D receptor genotype (Sellers et al., 2003). Even outside the Arctic zone, there seem to be differences in vitamin-D metabolism from one population to another. In particular, vitamin-D levels seem to be generally lower in darker-skinned populations (Frost, 2009).

These findings will force us to revisit the vitamin-D hypothesis of European skin color. According to this hypothesis, Europeans are white-skinned because their ancestors had to maintain the same level of vitamin-D synthesis at latitudes where UVB radiation is much weaker. This leaves unexplained the much darker skin of indigenous peoples at similar latitudes in northern Asia and North America. More importantly, it posits vitamin-D metabolism as a ‘given’ that human skin color has to adjust to, when in fact this metabolic pathway is just as amenable to natural selection as everything else.

There probably is a causal link between white skin and European vitamin-D metabolism, but the sequence of cause and effect may run in the opposite direction:

1. European skin whitened for an unrelated reason, probably sexual selection.

2. Because this depigmentation ensured abundant vitamin-D synthesis in the skin, there was a relaxation of selection pressure on vitamin-D metabolism. This would explain why, in comparison to other populations, Europeans convert less of it to its most active form and why it binds less effectively to the type of vitamin-D receptor that is most common among Europeans.

Unfortunately, our norms for adequate vitamin intake are based on subjects or populations of European origin. We are thus diagnosing vitamin-D deficiency in non-European individuals who are, in fact, perfectly normal. This is particularly true for African Americans, nearly half of whom are classified as vitamin-D deficient, even though few show signs of calcium deficiency—which would be a logical outcome. Indeed, this population has less osteoporosis, fewer fractures, and a higher bone mineral density than do Euro-Americans, who generally produce and ingest more vitamin D (Frost, 2009).

By pathologizing non-Europeans as being vitamin-D deficient, modern medicine is paving the way for programs that are well intentioned but ultimately tragic in their consequences: mass vitamin-D supplementation to be dispensed through the school system and awareness campaigns. Such public health programs have already been proposed for African Americans and northern indigenous peoples.

What will be the outcome of raising vitamin-D levels in these populations? Keep in mind that we are really talking about a hormone, not a vitamin. This hormone interacts with the chromosomes and gradually shortens their telomeres if concentrations are either too low or too high. Tuohimaa (2009) argues that optimal levels may lie in the range of 40-60 nmol/L. In non-European populations the range is probably lower. It may also be narrower in those of tropical origin, since their bodies have not adapted to the wide seasonal variation of non-tropical humans.

If this optimal range is continually exceeded, the long-term effects may look like those of aging:

Recent studies using genetically modified mice, such as FGF23-/- and Klotho-/- mice that exhibit altered mineral homeostasis due to a high vitamin D activity showed features of premature aging that include retarded growth, osteoporosis, atherosclerosis, ectopic calcification, immunological deficiency, skin and general organ atrophy, hypogonadism and short lifespan.

… after the Second World War in Europe especially in Germany and DDR, children received extremely high oral doses of vitamin D and suffered hypercalcemia, early aging, cardiovascular complications and early death suggesting that hypervitaminosis D can accelerate aging. (Tuohimaa 2009)

References

Frost, P. (2009). Black-White differences in cancer risk and the vitamin-D hypothesis, Journal of the National Medical Association, 101, 1310-1313.

Mekel-Bobrov, N., Posthuma D., Gilbert S.L., et al. (2007). The ongoing adaptive evolution of ASPM and Microcephalin is not explained by increased intelligence. Hum Mole Genet, 16, 600–8.

Rejnmark L, Jørgensen ME, Pedersen MB, et al. (2004). Vitamin D insufficiency in Greenlanders on a Westernized fare: ethnic differences in calcitropic hormones between Greenlanders and Danes, Calcif Tissue Int, 74, 255-263.

Rushton, J.P., Vernon, PA.., Bons, T.A. (2007). No evidence that polymorphisms of brain regulator genes Microcephalin and ASPM are associated with general mental ability, head circumference or altruism. Biology Letters-UK, 3, 157–60.

Sellers EAC, Sharma A, Rodd C. (2003). Adaptation of Inuit children to a low-calcium diet, Canadian Medical Association Journal, 168, 1141-1143.

Tuohimaa, P. (2009). Vitamin D and aging, Journal of Steroid Biochemistry and Molecular Biology, 114, 78-84.

Review of 2009

Before I make my predictions for 2010, let me review the ones I made for 2009:

The Neanderthal genome will be fully sequenced. There will be no evidence of interbreeding with modern humans (although proponents of the multiregional model will remain unconvinced). By comparing this genome with ours, we may reconstruct the genome of archaic humans who lived almost a million years ago and who were ancestral to Neanderthals and modern humans.

The Neanderthal genome was not fully sequenced this year. Because much of the reconstructed DNA turned out to be contamination from modern humans, the researchers had to start over. So far, there is no sign of Neanderthal admixture in the modern European genome, including the European variant of the microcephalin gene (which some had thought to have been of Neanderthal origin).

Meanwhile, work will begin on sequencing the genome of early modern humans (10,000 – 40,000 years ago). This project should ultimately prove to be more interesting by showing us how much modern humans have evolved during their relatively short existence. We will probably find out that John Hawks erred on the low side in concluding that natural selection had changed 7% of the human genome over the past 40,000 years.

The work has begun, at least for European populations, but it’s raising more questions than answers. The big question is the fate of the hunter-gatherers who inhabited Upper Paleolithic and Mesolithic Europe. Were they ancestral to present-day Europeans? Or were they replaced by a farming population from the Middle East? To date, the data indicate little genetic continuity between late hunter-gatherers and early farmers. On the other hand, the same data show little continuity between early farmers and present-day Europeans.

Perhaps founder effects are muddling the picture. Whenever some hunter-gatherers adopted agriculture, they and their descendants probably expanded considerably at the expense of neighboring groups. Early farmers would thus come from a very unrepresentative sample of late hunter-gatherers. The transition may have been just as bumpy between early farmers and later populations. Thus, the lack of genetic continuity could be more apparent than real.

In any case, paleo-geneticists should be looking not only at junk DNA but also at genes that have real-world effects. When did ancestral Europeans come to look the way they do now? Was it a gradual process that began when modern humans arrived in Europe some 35,000 years ago? Or did it happen rapidly?

We should also examine genes that regulate growth of brain tissue (like the aforementioned microcephalin variant). How intelligent were Europeans 30,000 years ago, 15,000 years ago, 5,000 years ago?

With the 150th anniversary of The Origin of Species, much will appear in 2009 about Charles Darwin and his life. We already know how he came up with his theory of evolution (Darwin salted away almost everything he wrote), although a few questions remain unanswered. What would he have done if he had lived longer? What did he have in mind for future projects?

Nothing really new has turned up. In 2009, historians questioned the view that Darwin deliberately held back his theory for two decades out of fear of a religious backlash. In fact, he was more afraid of not being taken seriously. He wished to build up his academic reputation before tackling the issue of evolution:

To use the modern jargon, he had to have the papers on the table to prove his worth. … Evolutionary ideas had emerged sensationally in the anonymously published Vestiges of the Natural History of Creation (1844), which could be pooh-poohed by the orthodox scientists of the day as a mishmash of half-baked ideas from the pen of a pseudo-scientist (it was subsequently revealed as the work of the antiquarian and publisher Robert Chambers). Darwin would not want to be taken lightly or dismissed as a mountebank: he was evidently a realist when it came to his career. (Fortey, 2009)

The Second Great Depression will not begin in 2009. In any case, what scares me is not the prospect of a sudden drop in the standard of living. Rather, it’s that of a gradual decline to almost half its current value. That scenario is scarier and likelier. And it’s probably already started. For the past fifteen years, median wages have stagnated despite decent economic growth. What will happen when growth stays in the 0-2% range?

The current recession is drawing to a close, but this should be no cause for self-congratulation. The coming decade will likely bring us stagflation, i.e., declining incomes and rising prices, especially for the basics of life (food, housing, oil, and most other commodities).

The cause? Globalization. The playing field is being leveled, and we’re competing more and more with the rest of the world for the basics of life. With free circulation of capital, goods, and labor—and that seems to be where our elites wish to go—incomes everywhere will tend to gravitate to the same level. There will still be income disparity within each country, perhaps even more (as in Latin America), but the average income level will be similar around the world, except for those countries that opt out of the globalist project.

Things might not be so bad for us if the world’s resources could be increased indefinitely. Our incomes could then stagnate while everyone else catches up (unlikely, though, since much of the world lacks the necessary social capital and political stability). In any case, even that scenario seems unrealistic. Demand is starting to outstrip supply for a number of key commodities, and not just oil. This is what the Club of Rome predicted back in 1972 in its report The Limits to Growth. Unfortunately, this pessimism seemed to be proven wrong when commodity prices fell into a long-term slump after the 1982 recession.

I suspect that warnings about peak oil are going unheeded now because similar warnings were made over thirty years ago. Just more of the same doom and gloom. Or so many think.

References

Endersby, J. (2009). Creative designs? How Darwin's Origin caused the Victorian crisis of faith, and other myths, TLS 7.3.16.

Fortey, R.A. (2009). How Darwin evolved, TLS 6.1.1.