Regory Cochran, Jason Hardy and Henry Harpending, co-authors of “Natural History of Ashkenazi Intelligence”, did not clearly address how disease genes could play a direct role in brain development. This theoretical gap and the societal implications of suggesting that a particular ethnic or religious group was genetically ‘smarter’ than others were controversial claims when their paper was published, and even more so today.
Not surprisingly, some prominent scientists have taken aim at this thesis, including eminent Harvard geneticist David Reich (who himself has come under fire for provocatively suggesting that “it is simply no longer possible to ignore average genetic differences among ‘races’”) and geneticist and science writer Adam Rutherford.
Reich argued in Who We Are and How We Got Herepublished in 2018, that genetic drift is the more likely reason for the higher rate of genetic diseases among Ashkenazi Jews.
Rutherford challenged the thesis from the beginning, and recently updated his critique based on the Norwich study findings. The Norwich researchers found genetic variants associated with diseases often seen in modern day Ashkenazi Jewish populations, such as a predisposition to certain cancers and delayed puberty. In a social media discussion of this “incredible” genetic research, Rutherford speculated that if these diseases were commonplace, it would throw doubt of categorizing them as so-called ‘Jewish diseases’ and linking them to the evolution of rising Jewish intelligence during the Middle Ages.
Since the surreally bad — but inexplicably popular — paper in  ‘Natural History of Ashkenazi Intelligence’ the assertion that higher frequency of the disease genes for Tay Sachs, Nieman Pick and Gaucher syndrome was a result of them bestowing heterozygous [survival] advantage. [The 2005 paper] suggested that this selection occurred during the last several centuries in response to the profession of money lending, which Jews were permitted to do. However, the new study shows that these disease genes were present much earlier … that there was a genetic bottleneck that predates the Norwich massacre, and that is much more likely to account for the higher frequency of disease genes. Genetics beats racism AGAIN.
Rutherford correctly points out that the Norwich study seems to raise questions about contemporaneously linking IQ and disease. He believes that a population bottleneck (“combined with endogamy”) is a much more parsimonious explanation than positive selection for the early presence and modern persistence of the relevant disease genes.
He makes a point, but it’s at least as speculative as the Jewish IQ thesis; the Jewish population could have (and likely did) suffer through numerous bottlenecks that tightened the relationship between these diseases and intelligence; in other words, the existing data do not rule out the Jewish intelligence thesis.
Rutherford, author of the controversial book “How to Argue With a Racist: What Our Genes Do (and Don’t) Say about Human Differences” also reveals his own ideological attitude in the odd statement that “genetics beats racism”. What does that mean exactly?
Selectively using ‘science facts’ to promote social and ideological values
The superficiality of Rutherford’s declaration can be seen by proposing a simple theoretical counterfactual: What if the Norwich skeletons hadn’t shown signs of modern Ashkenazi genetic disorders? Would such a finding have bolstered rather than ‘beaten’ racism? No — because scientific facts do not dictate values, such as racist or non-racist beliefs.
Genetic research can, of course, be used to support or refute beliefs that are based on factual (or supposedly factual) arguments. But the scientific data are independent of such social beliefs or values. In the case of racial prejudice, for instance, racists hold their bigoted opinions despite not because of scientific evidence. Importantly, however, this fact/value distinction also means that egalitarian values — notions of fairness, equality and the like — can be maintained irrespective of any facts of human biology.
And this is the problem with Rutherford’s position; in effect, he is tying egalitarian social ideals to scientific facts. But if the facts prove wrong, this undermines the egalitarian argument. Opposition to racial bigotry does not and should not depend on what science uncovers. Moral revulsion at the massacre of the Norwich Ashkenazim, for example, has nothing to do with what genetic science may tell us about the murdered Jews themselves. To repeat: evidence should not dictate values.
Yet the failure to clearly distinguish data from values goes a long way toward explaining some of the wider antipathy to evolutionary explanations of purported high Ashkenazi intelligence — that is, the erroneous belief that genetic evidence for enhanced cognitive abilities is simply a recipe for racism, which has led to determined efforts to discredit any such theories.
But what exactly is so threatening about the possibility of a genetic, population-based component to intelligence, whether in Ashkenazim or any other human group? Answering these questions in detail is beyond the scope of this discussion (although GLP’s Jon Entine and I addressed this issue at length elsewhere), so only a few remarks can be made below.
Human variation and difference
Human populations vary just as individual humans do. This is most obvious with skin color and other physical attributes. For instance, the Dutch are, on average, at the tallest end of the human height scale, the Inuit at the shortest. And just as the Inuit physique helps them cope with cold, so Tibetans’ physiology allows them to cope with extreme altitudes.
In sport, East Africans dominate long distance running, those of primarily West African descent sprinting, and Eurasians weightlifting. (It should be noted that Rutherford challenges many of the genetic explanations for observed racial differences in sporting abilities, an issue also examined by Jon Entine in Taboo: Why Black Athletes Dominate Sports and Why We’re Afraid to Talk about It.)
Some physical variation is genetic (eg, skin color or Tibetans’ adaptation to altitude), some environmental (eg, diet), and some a combination of both genes and environment — but none of this variation, these differencesautomatically provides grounds for racial discrimination or prejudice.
Yet if physical variation exists between individuals and populations, as for example David Reich has asserted, so too we should expect population-based variation in cognitive abilities (the human brain is, after all, as much a product of evolutionary forces as the human body ).
This argument should be banal: as the late EO Wilson once remarked: “Given that humankind is a biological species, it should come as no shock to find that populations are to some extent genetically diverse in the physical and mental properties underlying social behavior.”
Yet for many liberal-minded people, including Rutherford, such an argument is not unremarkable but, rather, remarkably dangerous. Why? Essentially, their fear is that if ‘intelligence’ is genetically influenced, then any social inequalities resulting from differences in cognitive abilities will be fixed and unchangeable. The more politically comforting view, therefore, is that cognitive differences are solely the result of existing social conditions — and, if so, ameliorative changes to the social environment can bring about desired changes to social inequality.
The natural selection of ‘intelligence’?
In the foreword to his Pulitzer Prize-winning Guns, Germs and Steel, biogeographer Jared Diamond provides an evolutionary explanation for possible differences in cognitive abilities in different human populations. The populations Diamond has in mind are Papua New Guineans and Europeans, but — in a twist to earlier, racist beliefs — he argues that natural selection would have favored greater intelligence among the former rather than the latter.
According to Diamond, features of the historical New Guinea environment (eg, chronic tribal warfare, difficulties in food procurement, rugged terrain, accidents and the like) would have created constant selective pressure for greater intelligence. In European societies, by contrast, selective pressures on cognitive abilities would have eased after the advent of agriculture, as sedentary lifestyles and greater political centralization reduced the impact of natural environmental hazards. Diamond concludes (though without evidence) that “modern ‘Stone Age’ peoples [such as Aboriginal Australians and New Guineans] are on the average probably more intelligent, not less intelligent, than industrialized peoples”.
Diamond’s thesis is tentative and likely mistaken. Yet so too is a similar argument presented by Cochrane and Harpending in The 10,000 Year Explosion (which also includes discussion of the Ashkenazi intelligence hypothesis). In Cochrane’s and Harpending’s view, post-agricultural lifestyles in Eurasia would have impacted human psychology, with selective pressures ‘domesticating’ or ‘taming’ human behavior to cope with the novel demands of increasingly dense populations. Hence, the evolved psychologies of different human groups likely vary due to differences in these groups’ evolutionary history. Controversially, Cochrane and Harpending go on to suggest that non-agricultural human populations may struggle to adjust to the (psychological) demands of modern urban life.
From a liberal political perspective, of course, Diamond’s evolutionary speculation (which elevates the ‘have nots’ of human history) is far more palatable than Cochrane’s and Harpending’s evolutionary account (which centers the ‘haves’). Yet this would mean that political biases — that is, political values — determine whether we accept or reject a particular evolutionary hypothesis.
The same appears to be the case with the Ashkenazi intelligence theory; that it can’t be correct because it offends liberal values. Yet again, this ignores the distinction between evidence (or putative facts) and values; Whether there are genetic factors to observed differences in cognitive ability, this in no way diminishes the egalitarian commitment to equality and respect for all of humanity.
The millennia long nightmare of Jewish persecution, epitomized by the medieval Norwich massacre and culminating in the horrors of the Holocaust, was driven by hatred and prejudice; that is, by warped human values not by the obvious fact that human populations differ both culturally and biologically.
Affirming human freedom and dignity
This discussion of the politicization of science should not overshadow the truly incredible genetic research on human remains from medieval Norwich. But I have done so in the hope of drawing the political poison from our ever-increasing knowledge of human evolution and biology. In the narrower case of human intelligence, there are many research and health reasons to examine and understand possible genetic influences on our brains, including cognitive abilities, and thus direct our social and educational policies in ways that best allow all individuals to flourish without discrimination. The alternative — to dismiss the very idea of a genetic component to intelligence — could perpetuate the very social inequality of which egalitarians rightly denounce.
EO Wilson said, thoughtfully, that “hope and pride and not despair are the ultimate legacy of genetic diversity”. That is how we should respond to the stunning findings about human history and origins made possible by modern genetic and genomic techniques — not with fearful misgivings, but with hope and pride.
Patrick Whittle has a PhD in philosophy and is a freelance writer with a particular interest in the social and political implications of modern biological science. Follow him on his website patrickmichaelwhittle.com or on Twitter @WhittlePM