Showing posts with label hunter-gatherers. Show all posts
Showing posts with label hunter-gatherers. Show all posts

Thursday, June 23, 2022

Ancestral East Asians and adaptation to coronaviruses

 



Early farming village in China (Wikicommons – Xinyang City Museum, Gary Todd)

 

Respiratory viruses began to propagate more easily when hunting and gathering gave way to farming and as settlements grew larger. Humans may have then evolved to use coronaviruses as a natural vaccine against deadlier respiratory diseases, like tuberculosis and pneumonia.

 

 

A new genomic study has found that East Asians had to adapt to epidemics of coronaviruses some 25,000 years ago. The authors looked at gene variants for proteins that interact with coronaviruses in five East Asian populations: Han Chinese (Beijing); Han Chinese (South China); Dai (Yunnan, China); Japanese; and Vietnamese. There were three main findings:

 

·         Ancestral East Asians had to adapt to coronavirus epidemics around 25,000 years ago

·         They adapted by acquiring mutations that are close to genes that regulate the development of lung tissue and other tissues affected by COVID-19

·         Those mutations either promote or block infection by coronaviruses (Souilmi et al. 2021, p. 3505).

 

The last finding is puzzling. Did those ancestral East Asians become more vulnerable or less vulnerable to coronaviruses? The authors simply say that half of those mutations from 25,000 years ago have “anti- or proviral effects” versus 29% of all proteins that interact with coronaviruses (Souilmi et al. 2021, p. 3509). Fine. But how many of those mutations were antiviral and how many proviral?

 

It might seem strange that natural selection would actually make people more susceptible to coronavirus infections. Yet such susceptibility could be beneficial. A viral infection can boost immunity to other pathogens, including deadly ones that cause tuberculosis, pneumonia, or pneumonic plague. Until recently, coronaviruses were typically mild in their effects, producing what we call the “common cold.” They may thus act as a natural vaccine against deadlier respiratory diseases (Frost 2020).

 

Respiratory diseases are believed to have become serious for humans when hunting and gathering gave way to farming. People became sedentary and their settlements grew larger with time, thus providing respiratory viruses with better conditions for propagation (Comas et al. 2013). This theoretical model is in conflict, however, with the above finding that ancestral East Asians began adapting to coronaviruses some 25,000 years ago, long before they adopted farming and became sedentary. We’re thus left with the unlikely conclusion that coronavirus epidemics began among scattered bands of hunter-gatherers.

 

The estimate of 25,000 years ago is probably wrong. The authors arrived at that figure by calculating the latest date when the ancestors of the four East Asian groups were still a single population. But East Asians are not descended from a single population. Their origins are best described by the "Two-Layer" (TL) hypothesis:

 

·         Modern humans spread into East Asia through a northern route and a southern route.

·         The southerners were then replaced to varying degrees by northerners who spread out of northeast Asia and successively occupied northern China, southern China, and Southeast Asia (Oxenham and Buckley 2016; Xu et al. 2006).

·         Thus, as you go farther south in East Asia, the population has a greater admixture from the earlier southern “layer”—from hunter-gatherers who closely resemble the relic groups that still exist in parts of Southeast Asia, i.e., the Andaman Islanders, the Aeta of the Philippines and the Maniq and Semang of the Malayan Peninsula.

 

Admixture from that older southern substrate pushes back in time the latest common ancestors, who never existed. Adaptation to coronaviruses therefore happened at a later date, probably when the “northerners” pushed into what is now northern China and adopted farming. They then grew in population, pushed farther south, and intermixed with the hunter-gatherers who lived there. 

 

 

References

 

Comas, I., M. Coscolla, T. Luo, et al. (2013). Out-of-Africa migration and Neolithic coexpansion of Mycobacterium tuberculosis with modern humans. Nature Genetics 45: 1176–1182. https://doi.org/10.1038/ng.2744

 

Frost, P. (2020). Does a commensal relationship exist between coronaviruses and some human populations? Journal of Molecular Genetics 3(2): 1-2. https://researchopenworld.com/does-a-commensal-relationship-exist-between-coronaviruses-and-some-human-populations/

 

Frost, P. (2022). A natural vaccine. Evo and Proud, February 21 http://evoandproud.blogspot.com/2022/02/a-natural-vaccine.html

 

Oxenham, M., and H.R. Buckley. (2016). The population history of mainland and island Southeast Asia, in M. Oxenham and H.R. Buckley (eds) The Routledge Handbook of Bioarchaeology in Southeast Asia and the Pacific Islands. Routledge.

 

Souilmi, Y., M.E. Lauterbur, R. Tobler, C.D. Huber, A.S. Johar, S.V. Moradi, W.A. Johnston, N.J. Krogan, K. Alexandrov, and D. Enard. (2021). An ancient viral epidemic involving host coronavirus interacting genes more than 20,000 years ago in East Asia. Current Biology 31(16), 3504–3514.e9. https://doi.org/10.1016/j.cub.2021.05.067

 

Xue, Y., T. Zerjal, W. Bao, S. Zhu, Q. Shu, J. Xu, R. Du, S. Fu., P. Li, M.E. Hurles, H. Yang, C. Tyler-Smith. (2006). Male demography in East Asia: A north-south contrast in human population expansion times. Genetics 172: 2431-2439, https://doi.org/10.1534/genetics.105.054270

Monday, June 13, 2022

Humans and the olfactory environment

 


Perfume burner, Egypt, c. 700-900 (Wikicommons, Musée du Louvre, Marie-Lan Nguyen)

 

We have sought to remake our environment in ever more appealing ways, including its smell. But the change hasn’t been one-way. By remaking our olfactory environment, we’ve ended up remaking ourselves.

 

 

I’ve published a new paper in Psych. When I wrote it, I had three aims:

 

·         Explain the concept of gene-culture coevolution

·         Provide a concrete example, i.e., how we have coevolved with the odors around us, not only in our ability to emit and sense them but also in our ability to represent them mentally

·         Develop the theoretical basis of gene-culture coevolution

 

Please feel free to comment. The following is the abstract:

 

 

As hunter-gatherers, humans used their sense of smell to identify plants and animals, to find their way within a foraging area, or to distinguish each other by gender, age, kinship, or social dominance. Because women gathered while men hunted, the sexes evolved different sensitivities to plant and animal odors. They also ended up emitting different odors. Male odors served to intimidate rival males or assert dominance. With the rise of farming and sedentism, humans no longer needed their sense of smell to find elusive food sources or to orient themselves within a large area. Odors now came from a narrower range of plants and animals. Meanwhile, body odor was removed through bathing to facilitate interactions in enclosed spaces. This new phenotype became the template for the evolution of a new genotype: less sensitivity to odors of wild plants and animals, lower emissions of male odors, and a more negative response to them. Further change came with the development of fragrances to reodorize the body and the home. This new olfactory environment coevolved with the ability to represent odors in the mind, notably for storage in memory, for vicarious re-experiencing, or for sharing with other people through speech and writing.

 

 

References

 

Frost, P. (2022). Humans and the olfactory environment: a case of gene-culture coevolution? Psych 4(2): 301-317. https://doi.org/10.3390/psych4020027  

 

Monday, March 28, 2022

Cognitive ability of indigenous Arctic peoples

 


In cold environments, human cognitive ability was an adaptation not to resource scarcity, as is often claimed, but to an abundance of resources that could be exploited only through a high level of planning, coordination, and tool development.

Caribou on Thelon River (Wikicommons – Cameron Hayne)

 

 

A reader has asked me, via Twitter: “Do you have any articles as to why the IQ of Siberian and Inuit peoples is lower than Northern Europeans despite similarly cold climate?”

 

Actually, indigenous Arctic peoples seem to be close to the global maximum of cognitive ability. It is also true, however, that the maximum is at more temperate latitudes, specifically within two broad regions:

 

·         East Asia – this is a “plateau” of populations with consistently high mean IQ, i.e., Chinese, Koreans, and Japanese. For Unz (2013), this plateau arose during the time of recorded history through the upper classes continually replacing the lower classes: “Each generation, the poorest disappeared, the less affluent failed to replenish their numbers, and all those lower rungs on the economic ladder were filled by the downwardly mobile children of the fecund wealthy.” A secondary cause was the imperial examination for civil-service jobs: "in China the proud family traditions would boast generations of top-scoring test-takers, along with the important government positions that they had received as a result."

 

·         Europe – this second plateau likewise arose during the time of recorded history, at first slowly during antiquity and then more rapidly during the late medieval to early modern period (Clark 2007; Woodley 2017). The latter increase was driven by expansion of the middle class, particularly by craftspeople who participated in the proto-industrial revolution of the 15th to early 19th centuries. There are thus “peaks” in the plateau, notably Ashkenazi Jews and the descendants of cottage-industry communities in Ulster, Lancashire, Yorkshire, Brittany, Flanders, Alsace, Westphalia, Saxony, the Zurich uplands, the Piedmont, and Lombardy (Cochran et al. 2006; Dunkel et al. 2019; Frost 2007; Piffer 2019; Seccombe 1992, pp. 205-217). Those communities contributed disproportionately to European population growth through early marriage and high childbearing, thus changing Europe’s cognitive landscape (Seccombe 1992, pp. 205-217). 


      The fatalism of serfs gave way to the rationalism of craftspeople: "The life-choices that structure family continuity through time had more predictable consequences; critical objectives could be achieved more regularly. Increasingly, the problem of uncontrolled randomness in life's fortunes was addressed through the calculus of probabilities, rather than through ritual, prayer, pleas for divine intercession, and stoicism ..." (Seccombe 1992, p. 212). 


There is another high-IQ peak among the Finns (Piffer 2019), for reasons that remain uncertain (Late transition from hunting to farming? Absence of serfdom?).

 

If cold climates select for cognitive ability, why do we find maximum cognitive ability at temperate latitudes? This is the apparent contradiction I address in my 2019 paper. In short, I argue that cold climates selected for cognitive ability only when humans were hunter-gatherers. This selection was driven not by resource scarcity, as is often claimed, but rather by an abundance of resources that could be exploited only through a high level of planning, coordination, and tool development (Frost 2019). With the advent of farming, and increasing social complexity, the pressure of selection shifted southward to environments that imposed new cognitive challenges: literacy and numeracy, state formation, laws and law enforcement, social stratification, expansion of the built environment, growth of music, literature, and the fine arts, development of religious beliefs and practices, construction of roads and other infrastructures, and so on.

 

This cognitive evolution initially went farther in the Middle East. Then, sometime around the 16th century, that region seemed to hit a ceiling as the pace of social complexification slowed down. The slowdown had several causes. First, there was demographic stagnation and loss of food production, due to the cumulative effects of erosion, salinization, and overgrazing. Second, there were ideological constraints. Although Islam was not alone in seeking to limit the free expression of ideas, it was more effective than Christianity in preventing the rise of a secular intellectual class that could spur progress in science and technology. Third, a true market economy failed to develop in the Middle East. The concept of trade was widely understood, but production of goods and services remained mostly within the household, i.e., family members, servants and, more broadly, relatives and in-laws. As a result, the market could not replace kinship as the main organizing principle of society.

 

Finally, and perhaps most importantly, cognitive evolution continued in Europe and East Asia because their lower classes were continually replaced, demographically, by their middle and upper classes. This process, described by Gregory Clark for England and Ron Unz for China, has three key elements:

 

1. Social class correlates positively with IQ.

 

2. Social class correlates positively with reproductive success. Lower classes fail to reproduce themselves, whereas higher classes more than reproduce themselves.

 

3. There are no barriers to downward social mobility. Lower classes are thus continually replaced by the demographic overflow of higher classes (Clark 2007; Unz 2013).

 

These three elements are not universal. Hunter-gatherers and simple farming societies have little or no social stratification. Other societies are stratified but have no State that can monopolize the use of violence. There is instead an ongoing free-for-all that selects for ruthlessness, charisma, and the ability to mobilize male violence. Finally, some societies are so stratified that downward mobility is impossible. Social classes are permanent “castes.”

 

In sum, cognitive evolution was initially driven by cold climate at higher latitudes and later by increasing social complexity at lower latitudes. Some higher-latitude groups then moved south to exploit the opportunities being created by increased social complexity. Those groups were not the ones who initiated the transition to farming, sedentism, and social complexity. Instead, they arrived after the fact, being cognitively pre-adapted for the opportunities that others had created and thus better able to pursue this evolutionary trajectory (Frost 2019).

 

Studies of cognitive ability in Arctic peoples

 

To return to the original question, indigenous Arctic peoples seem to be close to the global maximum of cognitive ability, but the evidence is limited and questionable. This situation has three causes:

 

·         Difficulties in administering IQ tests to people who are unfamiliar not only with modern concepts but also with the modern question-and-answer paradigm. Traditionally, indigenous Arctic people learn not by asking questions but by observing a “master” and then copying whatever he or she does. Asking questions can also be impolite, especially if too many are asked in rapid succession. I should point out that the same difficulties used to exist in Western societies. People in Britain and North America were unfamiliar with standardized written tests until the rise of publicly funded schools and competitive civil-service exams in the late 19th century (Wikipedia 2022). It wasn’t because people got smarter that mean IQ rose during the 20th century. They just got better at taking tests.

 

·         Ideological constraints. IQ research was discouraged in the Soviet Union, partly because of the dominant belief in environmental determinism and partly because of a desire to avoid stigmatizing certain national groups. A ban on intelligence testing was thus imposed in 1936 and gradually lifted only in the 1960s and early 1970s (Grigoriev and Lynn 2009).

 

·         Lack of research on alleles associated with educational attainment. This avenue of research offers a better measure of innate cognitive ability but is still in its infancy with respect to Arctic peoples. I know of only one relevant study. Piffer (2013) found that the Met allele at COMT, a gene linked to executive function, working memory, and intelligence, is more frequent in farming societies than in hunter-gatherers, with one interesting exception: "hunter-gatherers living at high latitudes (Inuit) show high frequencies of the Met allele, possibly due to the higher pressure on technological skills and planning abilities posed by the adverse climatic conditions near the North Pole."

 

 

Siberia (Evenk, Altai, Yakuts)

 

In Siberia, IQ tests were conducted in 1929 and later in 2015-17. The first period saw testing among the Evenk of the northeast and the Altai of the south.

 

When a Binet test was administered to 5 Evenk children 7 to 19 years old, the mean score was 70.16. The study’s author reported that the children had trouble understanding units of measurement and number.

 

He reported that when Evenk children were questioned about devices for measurement, they did not have the concept of an absolute unit of measurement. They thought that the unit changed with the material measured. Bulanow [the author] reported further that when he asked Evenk adults how many children they had “It was difficult, almost impossible, to get from parents precise information as to how many of their children were alive, how many of their children had died, what was the age of their children, and so on.” (Grigoriev and Lynn 2009, p. 449)

 

When a Binet test was administered to 52 Altai children 8 to 20 years old, the mean score was 66.9. Again, the subjects had problems with units of measurement: “when they were questioned about the length of a meter, the Altai would often ask: “Which meter?” They thought that the meter in one shop could be longer than in another” (Grigoriev and Lynn 2009, p. 450). Nonetheless, adult Altai showed remarkable aptitudes in other areas of life:

 

Although adult Altai performed calculations poorly at the time of study, they showed a remarkable ability for visual estimation of large quantities. A herdsman, who could count only to 20–30, noticed very well the absence of one horse, cow or sheep in a herd of many hundreds. He looked at a huge herd and noted that a particular cow was absent. Another example of the great visualization ability of the Altai was that they could remember and showed the way through wild territory, where they had been only once many years previously (Grigoriev and Lynn 2009, p. 450)

 

In recent years, there has been a renewed effort to study cognitive ability among indigenous Siberian peoples:

 

·         Shibaev and Lynn (2015) tested 29 Evenk children and found a mean score of 80. Also tested were 13 ethnic Russian children, who had grown up under similar conditions. Their mean score was 85.

·         Shibaev and Lynn (2017) tested 287 Yakut children and 52 ethnic Russian children from eastern Siberia. The mean score was 97.0 for the Yakuts and 97.9 for the ethnic Russians.

·         Shibaev et al. (2020) tested 518 Yakut children and 956 ethnic Russian children. The age range was wider than in previous studies, and the IQ difference between the two groups seemed, in general, to be greater at younger ages than at older ones. At 9 years of age the Russians had a 3 point advantage over the Yakuts, whereas at 17 this advantage was zero. Yakut children may have a slower rate of cognitive maturation. There is also some doubt as to the comparability of the two groups, since the Russians came largely from a city (Tomsk), while the Yakuts came from a city (Yakutsk) and a small town (Vilyuysk).

 

The authors note that the differences between ethnic Russians and indigenous Siberians can be largely explained by an urban-rural divide:

 

[…] for both Russians and Yakuts the IQs of the city samples were higher than the IQs of the village samples. For the Russians, there was a difference of 10.5 IQ points between the combined city samples and the village sample, while for the Yakuts the difference was 4.4 points. The higher IQs of the city samples is a common result found in many previous studies reporting that urban populations typically obtain higher IQs than rural populations. (Shibaev and Lynn 2017)

 

Shibaev and Lynn (2017) attribute this urban-rural divide to differential migration: smarter people move to the city, and dumber people stay home in the village. I would argue that villagers are less familiar with modern concepts and the modern question-and-answer paradigm.

 

Arctic North America (Inuit)

 

Like indigenous Siberians, the Inuit (Eskimos) display an unusual ability to find their way across vast expanses of territory, a task that requires remembering huge amounts of visuospatial data. Adults are reported to have an "extraordinary ability to find their way through what appears to be a featureless terrain by remembering visual configurations [...]. According to some reports, such memories persist for long periods of time. Elderly hunters have succeeded in guiding parties through terrain seen only in their youth" (Kleinfeld 1973, p. 344)

 

Nonetheless, Inuit have done poorly in most IQ studies, especially in older studies of traditional Inuit. Kleinfeld (1973) cites several reasons:

 

Unfamiliarity with test-taking:


Eskimos' performance on standardized tests may be lowered because of their unfamiliarity with test-taking conventions and because of cultural biases of the tests. Eskimos, for example, may find it difficult to view a trivial, pointless task such as copying a design or running through a finger maze as worthy of serious concentration and maximum effort.

 

Racial context of test-taking


Eskimos, especially young males, have become increasingly antagonistic to any sort of testing and research, which they view as another form of White exploitation. Co-operation, if given at all, may be perfunctory, resulting in extremely low test scores.

 

Extreme caution during test-taking


Eskimos, especially males, have been socialized into extreme caution before making a judgment. The hunter is taught never to take risks, never to call out a hasty evaluation because the penalty can be swift death not only for himself but also for others who rely on his decision. […] Especially more traditional Eskimos tend to have a slow, cautious response style which may depress their scores on speeded figural tests.

 

Slower rate of cognitive maturation


[There is] some evidence that Eskimos' peak performance on figural tests occurs later than that of Western groups. [This] raises the possibility of a slower rate of cognitive maturation among Eskimos which would be consistent with their somewhat slower rate of physical maturation […]. If this is the case, the usual age-matched comparisons between Western and Eskimo children on figural tests may be misleading.

 

In their reviews of the literature, Kleinfeld (1973) and Taylor and Skanes (1976) note that Inuit generally outperform Whites on visual discrimination and spatial tests. Interestingly, Inuit children do almost as well as non-Inuit children on English spelling tests while doing poorly in other aspects of English, perhaps because they memorize the shapes of words. On the other hand, they underperform White children on verbal-educational and inductive reasoning tests. The latter finding may reflect lack of familiarity with English in earlier studies. When Taylor and Skanes (1976a) tested Inuit and White first graders for vocabulary and arithmetic, using the Wechsler Pre-School and Primary Scale of Intelligence, they found no significant differences between the two groups in spatial, verbal-educational, and inductive reasoning abilities. When the same researchers tested a larger sample of Inuit and White children from different age groups, using a series of digit span tests and Raven’s progressive matrices, they found that the Inuit children caught up with the White children with increasing age on the digit span tests and that the Inuit children outperformed the White children on the Raven’s progressive matrices (Taylor and Skanes 1976b).

 

Wright et al. (1996) tested the IQ of Inuit children in Arctic Quebec during the first two grades of school, using Coloured Progressive Matrices (CPM). Mean scores were consistently higher than age-appropriate U.S. norms and were comparable with data for White children in southern Quebec. In addition, the scores of children with two Inuit parents did not differ significantly from those of children with mixed Inuit/White heritage. 

 

Nonetheless, Inuit children do worse at school than other children, having not only lower rates of academic achievement but also higher dropout and suicide rates. For Clifton and Roberts (1988), the reason is inferior self-perception of their ability and less active involvement in the educational process. This mindset may be rooted in the traditional Inuit attitude toward education, where the “student” simply observes and copies the “master.”

 

In sum, the Inuit seem to have about the same level of cognitive ability as people of European origin, with perhaps some interesting differences: superior visuospatial skills, higher risk aversion, slower cognitive maturation, and a more imitative and less inquisitive approach to learning. It is still unclear whether they have lower verbal-educational and inductive reasoning abilities. In their review, McShane and Berry (1988, p. 392) conclude that indigenous Arctic peoples do well relative to Euroamerican norms, showing “high performance on both piagetian and psychometric tests of visually based spatial, analytic, disembedding, and inductive abilities.” The two researchers attribute reports of lower verbal ability to second-language familiarity with the test language. Clearly, more research is needed, if only to adapt the northern educational system to Inuit needs.

 

It must be said that the Inuit are ill-suited to the Western model of education and, more broadly, to the Western model of sedentism, individualism, and asociality. Young Inuit feel useless in that kind of society, and all too many end up committing suicide.

 

Conclusion and discussion

 

We have only a few studies of cognitive ability among indigenous Arctic peoples. This paucity is due only in part to methodological problems. In the Soviet Union, all IQ research ceased between 1936 and the 1960s. It has recommenced among indigenous Arctic peoples only over the past decade. Meanwhile, similar research in Canada and the U.S. has been nonexistent since the 1990s.

 

If we look at the existing research, we may doubt whether the subjects were fully familiar with test-taking and the modern question-and-answer paradigm. Another problem is that indigenous Arctic children seem to have a slower rate of cognitive maturation. If Yakut subjects are still catching up to Russian subjects at the age of 17, it might be more appropriate to compare the two groups at an older age. In practice, this would be difficult because young adults start following different life paths after 17. Finally, indigenous Arctic peoples may allocate their mental capacities differently, being better, for instance, at processing visuospatial data than other kinds of information. Since IQ tests have been designed for Western children, the test design may not correspond to the mental tasks that some non-Western groups prioritize.

 

Yes, dear reader, I hear you. If people do well on one cognitive task, they should do well on all others, shouldn’t they? Isn’t that what the g factor is all about? In other words, people will tap into the same mental capacity for any cognitive task.

 

The relative strength of the g factor, however, has been calculated from subjects in Western or Westernized societies. Does it have the same strength across different mental domains among people who until recently were nomadic hunters? Anthropologists, like John Berry, have argued that hunters allocate much more of their mental capacity to visuospatial orientation:

 

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)

 

It would be interesting to find out whether these skills have become hardwired to some degree through gene-culture coevolution. Are hunting peoples inherently better at orienting themselves in space? Did vast expanses of land favor the success of people who could more easily find their way across vast expanses of land? To answer that question, John Berry launched a project in the late 1980s with the geneticist L.L. Cavalli-Sforza. They wished to recruit participants among the Inuit of northern Canada and use aptitude for soapstone carving as a means to measure visuospatial skills:

 

With most individuals having had a reasonably fair chance and stimulation to become artists, one is in a better condition to study possible genetic factors contributing to artistic talent, if any. Another great advantage of carrying out this study among the Inuit is the frequency with which adoptions (also early ones, at birth) occur in this population. Frequencies of adoptions reported during the meeting varied from 15% to 30%. Adoptions allow one to distinguish cultural from biological inheritance by studying correlations of adopted children with foster relatives on one hand and biological relatives on the other. (Berry and Cavalli-Sforza 1986)

 

Cavalli-Sforza was thinking, here, along the lines of gene-culture coevolution. He had in fact been one of the founders of that paradigm, although he preferred the term “dual inheritance theory.” Now, he would have a chance to investigate it in the field.

 

Then, suddenly, he backed out of the project. For “health reasons.” Yet neither his biography nor his autobiography mentions any health problems during that period of his life.

 

 

References

 

Berry, J.W. (2008). Models of Ecocultural Adaptation and Cultural Transmission: The Example of Inuit Art, paper presented at the conference Adaptation et socialisation des minoritiés culturelles en région, June 3-4, Quebec City.

 

Berry, J.W., and L.L. Cavalli-Sforza. (1986). Cultural and Genetic Influences on Inuit Art. Report to the Social Sciences and Humanities Research Council of Canada, Ottawa.

 

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

 

Clifton, R.A. and L.W. Roberts. (1988). Social psychological dispositions and academic achievement of Inuit and non-Inuit students. Alberta Journal of Educational Research 34(4): 332–343.

 

Cochran, G., J. Hardy, and H. Harpending. (2006). Natural history of Ashkenazi intelligence. Journal of Biosocial Science 38(5): 659–693. https://doi.org/10.1017/S0021932005027069

 

Dunkel, C.S., M.A. Woodley of Menie, J. Pallesen, and E.O.W. Kirkegaard.  (2019). Polygenic scores mediate the Jewish phenotypic advantage in educational attainment and cognitive ability compared with Catholics and Lutherans. Evolutionary Behavioral Sciences 13(4): 366-375.  https://psycnet.apa.org/doi/10.1037/ebs0000158

 

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  

 

Frost, P. (2019). The Original Industrial Revolution. Did Cold Winters Select for Cognitive Ability? Psych 1(1): 166-18. https://doi.org/10.3390/psych1010012  

 

Grigoriev, A, and R. Lynn. (2009). Studies of socioeconomic and ethnic differences in intelligence in the former Soviet Union in the early twentieth century. Intelligence 37: 447-452, https://doi.org/10.1016/j.intell.2009.05.005  

 

Kleinfeld, J.S. (1973). Intellectual Strengths in Culturally Different Groups: An Eskimo Illustration. Review of Educational Research 43(3): 341-359.

https://doi.org/10.3102%2F00346543043003341  

 

McShane, D., and J.W. Berry. (1988). “Native North Americans: Indian and Inuit Abilities.” In: S.H. Irvine and J.W. Berry (eds.) Human Abilities in Cultural Context (pp. 385-426), Cambridge: Cambridge University Press.

 

Piffer, D. (2013). Correlation of the COMT Val158Met polymorphism with latitude and a hunter-gather lifestyle suggests culture-gene coevolution and selective pressure on cognition genes due to climate. Anthropological Science 121(3): 161-171. https://doi.org/10.1537/ase.130731  

 

Piffer, D. (2019). Evidence for Recent Polygenic Selection on Educational Attainment and Intelligence Inferred from Gwas Hits: A Replication of Previous Findings Using Recent Data. Psych 1(1): 55-75. https://doi.org/10.3390/psych1010005    

 

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

 

Shibaev, V., A. Grigoriev, E. Valueva, and A. Karlin. (2020). Differential Item Functioning on Raven’s SPM+ Amongst Two Convenience Samples of Yakuts and Russians. Psych 2(1):44-51. https://doi.org/10.3390/psych2010005

 

Shibaev, V. and R. Lynn. (2015). The Intelligence of the Evenk/Tungus of the Russian Far East. Mankind Quarterly 56(2): 202-207. http://doi.org/10.46469/mq.2015.56.2.7  

 

Shibaev, V. and R. Lynn. (2017). The Intelligence of Yakuts and Ethnic Russians in Yakutia. Mankind Quarterly 57(4): 680-686. http://doi.org/10.46469/mq.2017.57.4.11  

 

Taylor, L.J., and G.R. Skanes. (1976a). Cognitive abilities in Inuit and White children from similar environments. Canadian Journal of Behavioural Science 8(1): 1-8.

https://psycnet.apa.org/doi/10.1037/h0081930  

 

Taylor, L.J., and G.R. Skanes. (1976b). Level I and level II intelligence in Inuit and White children from Similar Environments. Journal of Cross-Cultural Psychology 7(2): 157-168.

https://doi.org/10.1177%2F002202217672004

 

Unz, R. (2013). How Social Darwinism made modern China, The American Conservative, March/April, 16-27. https://www.theamericanconservative.com/articles/how-social-darwinism-made-modern-china-248/  

 

Wikipedia (2022). Test (assessment). https://en.wikipedia.org/wiki/Test_(assessment)#West  

 

Woodley, M.A., S. Younuskunju, B. Balan, and D. Piffer. (2017). Holocene selection for variants associated with general cognitive ability: comparing ancient and modern genomes. Twin Research and Human Genetics 20: 271-280. https://doi.org/10.1017/thg.2017.37   

 

Wright, S.C., D.M. Taylor, and K.M. Ruggiero. (1996). Examining the Potential for Academic Achievement among Inuit Children: Comparisons on the Raven Coloured Progressive Matrices. Journal of Cross-Cultural Psychology 27(6): 733-753.

https://doi.org/10.1177%2F0022022196276006  

Tuesday, March 24, 2020

The myth of selective neutrality



Paleolithic tent (Wikicommons - Michal Mañas). Did Europeans lose haplogroup U because they were replaced by farmers from the south? Or because they needed less energy for body heat?



Blood group systems have long been used to reconstruct prehistory. A good example is the Diego antigen. One of its alleles, DI*A, has helped us chart the prehistory of indigenous peoples in the Americas. Among other things, we have learned that most of them originated in Siberia some 12,000 years ago. This is not the case with the Eskimo-Aleut and Na-Dene peoples, who seem to have entered North America later. 

It’s assumed here that the Diego antigen has mutated at a steady rate and that the mutations have displaced earlier ones at a steady rate. So this antigen can act as a clock. If two populations have separated from each other, we can estimate their time of separation by measuring the mean genetic difference between them at the Diego antigen.

The "clock" assumption has its limitations. Diego mutations are neither kept nor lost at a constant rate. Both processes can be slowed down or speeded up by natural selection: 

Our study also revealed a significant correlation between DI*A allele frequency and warm tropical conditions, domesticated crop type, and presence of disease-carrying vector species. The circumscribed areas defined by these factors compose a mosaic of specific biocenoses and pathocenoses. It is thus reasonable to consider natural selection in the distribution of human genetic polymorphisms. (Bégat et al. 2015)

It's widely believed that all blood groups have the same survival value, so differences between them should be "selectively neutral." That belief is mistaken. In fact, nothing in the genome is truly of neutral value, not even noncoding genes that supposedly do nothing. Even if a gene doesn't code for anything, it still affects the spatial configuration of genes on the chromosome, thus altering how one gene may regulate another. 

According to a recent study, 80% of our genome has some kind of function, even noncoding genes (The ENCODE Project Consortium 2012). Indeed, such genes may have disproportionately contributed to human evolution. Comparison of our genome with other primate genomes has shown that almost all human-specific deletions are in noncoding regions (Bae et al. 2015). Furthermore, DNA is mostly noncoding in human accelerated regions (HARs)—genomic regions that have been well conserved throughout vertebrate evolution but are strikingly different in humans, perhaps in ways that alter how coding genes regulate each other (Bae et al. 2015). This would be consistent with the belief that our ancestors evolved largely through new ways of regulating existing systems, particularly the pace and timing of development (King and Wilson 1975).


Loss of haplogroup U: population replacement or change in natural selection?

Let's now look at haplogroup U. This, too, is assumed to be "selectively neutral" and is used to reconstruct prehistory, specifically the replacement of hunter-gatherers by farmers in Europe. Haplogroup U is a group of mitochondrial genes that was widespread among Mesolithic hunter-gatherers throughout Europe and is now common only among the Sami of Finland and the Mansi of northwestern Siberia, both of whom were hunter-gatherers until recently (Derbeneva et al. 2002). Indeed, according to ancient mtDNA from central and western Europe, the population frequency of haplogroup U shows a sharp break at the time boundary between late hunter-gatherers and early farmers (Bramanti et al. 2009). That break strongly suggests that European hunter-gatherers were largely replaced by farmers spreading into Europe from the Middle East.

Yet things are not always as they seem. In Denmark, haplogroup U persisted at high frequencies long after the transition to farming, in fact as late as the Early Iron Age (Melchior et al. 2010). In Latvia and Ukraine it persisted into Neolithic times (Jones et al. 2017).

Perhaps haplogroup U disappeared because it ceased to be adaptive and was removed by natural selection. This haplogroup shifts the energy balance away from ATP synthesis and toward production of body heat—a useful cold adaptation for hunter-gatherers, who had to sleep in makeshift shelters and pursue game animals in all kinds of weather (Balloux et al. 2009; Montiel-Sosa et al. 2006). Farmers slept in a warmer environment and could more easily plan their outdoor activities.

This being said, the loss of haplogroup U was not the only genetic change across the Mesolithic-Neolithic divide. Were those other changes due to natives being replaced by farmers from the Middle East? Or was natural selection again responsible? Researchers have tried to exclude the second cause by examining how noncoding genes changed across the divide, on the assumption that such genes are generally non-functional and make no difference to one’s chances of survival and reproduction. As we've seen, that assumption is unfounded.

Clearly, some of this genetic change was due to natural selection. I mentioned the shift in energy balance, but there were others. Farmers had less need for odor recognition, monotony avoidance, and sensation seeking (Majid and Kruspe 2018; Zuckerman 2008). They also had to process reciprocal obligations with a larger number of people while interacting less, on average, with each person. All in all, farming did not impose the same demands on mind and body. Going from one way of life to the other required many physiological adjustments.

To explain the genetic divide between hunter-gatherers and farmers, we should also allow for founder effects. When bands of hunter-gatherers are given the opportunity, only a few will choose to become farmers. Because this minority is a small sample of the hunter-gatherer gene pool, the new farming population will differ genetically from the previous one in many random ways.


Conclusion

When reconstructing the past, particularly the transition from hunting and gathering to farming, we shouldn't interpret genetic change solely in terms of one population replacing another. Some of the change may also be due to a new regime of natural selection, as well as founder effects.

I once made this point to Greg Cochran, and his reply was that changes in natural selection couldn't possibly account for all of the genetic change we see in ancient DNA between late hunter-gatherers and early farmers. True, but that's not my point. Some population replacement did happen, but its magnitude is exaggerated by a methodology that attributes all genetic change to that one factor alone. 


Interview with Grégoire Canlorbe

I was recently interviewed by Grégoire Canlorbe, a young French author and scholar. The interview covers a variety of topics and can be read in its entirety (in two parts) at American Renaissance:

https://www.amren.com/features/2020/03/how-did-whites-get-their-appearance/ 
https://www.amren.com/features/2020/03/why-are-human-groups-so-different/

Une traduction française est disponible sur le site Evopsy de Philippe Gouillou :

http://www.evopsy.com/concepts/coevolution-frost.html
http://www.evopsy.com/concepts/hbd-frost.html


References

Bae, B-I., D. Jayaraman, and C.A. Walsh. (2015). Genetic changes shaping the human brain. Developmental Cell 32: 423-434. 
https://www.sciencedirect.com/science/article/pii/S1534580715000787

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 of the Royal Society B. Biological Sciences 276: 3447-3455. 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2817182/

Bégat, C., Bailly, P., Chiaroni, J., & Mazières, S. (2015). Revisiting the Diego Blood Group System in Amerindians: Evidence for Gene-Culture Comigration. PloS one 10(7), e0132211.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4493026/

Bramanti, B., M.G. Thomas, W. Haak, M. Unterlaender, P. Jores, K. Tambets, I. Antanaitis-Jacobs, M.N. Haidle, R. Jankauskas, C.J. Kind, et al. (2009). Genetic discontinuity between local hunter-gatherers and Central Europe's first farmers. Science 326: 137-140.
http://roceeh.mediatis.de/fileadmin/download/Publications/Bramanti_Sci09_Meso_Neo.pdf

Derbeneva, O.A., E.B. Starikovskaya, D.C. Wallace, and R.I. Sukernik, (2002). Traces of early Eurasians in the Mansi of Northwest Siberia revealed by mitochondrial DNA analysis. American Journal of Human Genetics 70: 1009-1014. 
https://www.sciencedirect.com/science/article/pii/S0002929707603085

Jones, E.R., G. Zarina, V. Moiseyev, E. Lightfoot, P.R. Nigst, A. Manica, et al. (2017). The Neolithic transition in the Baltic was not driven by admixture with early European farmers. Current Biology 27(4): 576-582.
https://www.sciencedirect.com/science/article/pii/S0960982216315421

King, M-C, and A.C. Wilson. (1975). Evolution at two levels in humans and chimpanzees. Science 188: 107-116.
http://hydrodictyon.eeb.uconn.edu/people/schwenk/KingWilsonHumansChimps75.pdf

Majid, A., and N. Kruspe. (2018). Hunter-gatherer olfaction is special. Current Biology 28: R108-R110. 
https://www.sciencedirect.com/science/article/pii/S0960982217316160

Melchior, L., N. Lynnerup, H.R. Siegismund, T. Kivisild, and J. Dissing. (2010). Genetic diversity among ancient Nordic populations. PLoS One 5(7): e11898
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912848/

Montiel-Sosa, F., E. Ruiz-Pesini, J.A. Enriquez, A. Marcuello, C. Diez-Sanchez, J. Montoya, D.J. Wallace, and M.J. López-Pérez, (2006). Differences of sperm motility in mitochondrial DNA haplogroup U sublineages. Gene 368: 21-27.
http://cnc.cj.uc.pt/BEB/private/pdfs/2007-2008/RepBiology/ExtraBibliog/MontielSosa2006.pdf

The ENCODE Project Consortium. (2012). An integrated encyclopedia of DNA elements in the human genome. Nature 489: 57-74 
https://www.nature.com/articles/nature11247

Zuckerman, M. (2008). Genetics of Sensation Seeking. In J. Benjamin, R.P. Ebstein, and R.H. Belmaker (Eds) Molecular Genetics and the Human Personality, (pp. 193-210). Washington D.C.: American Psychiatric Publishing Inc.
https://books.google.ca/books?id=mfANqS-SnwgC&printsec=frontcover&hl=fr&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false