To be fair, even before the new research hit the scene, we had good reason to think that heritability involved many genes of small effect. One reason came from selective breeding experiments on other animals. In a classic study, psychologists bred one line of mice for a tendency to boldly explore open spaces, and another for a tendency to nervously avoid them (see the graph below). If the relevant behaviors came from just a handful of genes, the two lines would have separated in a few generations, then ceased to budge any further. Instead, they showed a steady, linear divergence across dozens of generations - exactly as we'd expect if the traits were shaped by a large number of genes with small effects.
– Steve Stewart-Williams, "Top 10 Most Replicable Findings from Behavior Genetics, Part 1"
So far as I’m aware, all the major controversies surrounding genes and intelligence since 1990 have concerned either race differences or dysgenics. In other words: those who’ve limited themselves purely to discussing individual differences have largely avoided scandal. The last three decades could thus be seen as the era behaviour genetics entered the mainstream.
So far as I’m aware, all the major controversies surrounding genes and intelligence since 1990 have concerned either race differences or dysgenics. In other words: those who’ve limited themselves purely to discussing individual differences have largely avoided scandal. The last three decades could thus be seen as the era behaviour genetics entered the mainstream.
Steve Pinker’s book The Blank Slate, which expertly debunked the myth that genes don’t matter for intelligence (and other psychological traits), was a finalist for the Pulitzer Prize – arguably the second most prestigious prize in writing. What’s more, both twin and genome-wide association studies studies of intelligence were routinely published in leading journals like Nature Genetics. It was in era in which you could mention in polite company that, actually sir, intelligence is a heritable trait.
That era may be coming to an end.
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Opposition to behaviour genetics ramped up further when Paige Harden’s book The Genetic Lottery was published last year. Unlike Plomin, who keeps his political cards close to his chest, Harden is an out-and-out progressive. Back in 2017, she co-authored an article in Vox denouncing Charles Murray for “peddling junk science about race and IQ”. (See here for a rebuttal.) And she denounced him once again in The Genetic Lottery. She also denounced the “racist” Arthur Jensen, and dedicated an entire chapter to what she calls “Anti-Eugenic Science and Policy”.
However, these attempts to mollify her progressive readers were not enough to save Harden from some equally hostile reviews. Marcus Feldman and Jessica Riskin’s 5,000 word review in the New York Review of Books was particularly unkind.
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Attacks on behaviour genetics have intensified in just the last month, following the mass shooting in Buffalo, New York. As I noted previously, the perpetrator of that mass shooting published a manifesto, which cited various papers from the field of behaviour genetics. This, in turn, prompted two viral Twitter threads suggesting that such papers “should not be published” and that “the current anti-eugenics discourse is not effective”.
It also led to a remarkable hit piece in the Daily Beast calling for nothing less than the “deplatforming” of behaviour genetics. According to the author, “The slow response to The Bell Curve has helped similar work live on today in the hands of others, like psychologist Stuart Ritchie … and behavioral geneticist Kathryn Paige Harden”. He focusses particular ire on the latter, who has supposedly helped to legitimise “crypto-race science”. Describing behaviour genetics as “ethically abhorrent”, the author says that publishers “should refuse to participate” and must recognise the field is “actively harming people”.
After amassing legions of evidence from twin studies, family studies and now genome-wide association studies, how has behaviour genetics found itself in this position? One factor is obviously the Great Awokening, which has empowered all manner of ideological science deniers. Another is the problem of “missing heritability” – the fact that h-squared estimates derived from SNP data are generally lower than those derived from twin and family studies.
But I would suggest there’s a more general problem. Anyone who takes the ideological objections to group differences research to their logical conclusions will end up opposing individual differences research as well.
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In other words, if you grant that scientific claims can be “racist” then you’ve opened the door to your scientific claims being called “racist”. And if you concede that “genes contribute to group differences in intelligence” implies some groups are “inferior”, then you can’t deny that “genes contribute to individual differences in intelligence” implies some individuals are “inferior”. Either statements about genes and intelligence are scientific, regardless of whether they pertain to groups or individuals, or they’re not.
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Harden’s position seems to be: hereditarianism isn’t racist; it’s just that anyone who’s ever argued for it is. This inconsistency illustrates the bind that she and her progressive colleagues have gotten themselves into. To deflect criticism and make safe their research funding, they’ve been telling activists what they want to hear: “Murray and Jensen are terrible, and our work has nothing to do with them”. Meanwhile, they’ve been continuing the same basic research tradition – gathering more and more evidence that genes matter for social inequality.
Drawing a distinction between “good” research on individual differences and “bad” research on race differences hasn’t worked. It’s time to abandon the idea that scientific claims can be “racist”, or that they’re really claims about “inferiority”, and just look at the data dispassionately.
I have an essay in Nature this week on how science has shaped human identity, part of their 8-part anniversary series on the history of science over the last 150 years. The response has been overwhelmingly positive — thank you!
There’s always a few cranks, though. What has stuck in some people’s craw is my distinction between science and scientism. Science is a set of practices to investigate…
The First Lawyer of Behavior Genetics Speaks Out Against Plomin's Blueprint
The First Lawyer of Behavior Genetics Speaks Out Against Plomin’s Blueprint
In his latest post, the behavioral psychologist Eric Turkheimer writes that in Blueprint, Robert Plomin appropriates his ideas without attribution and twists their meaning. You may have heard of the so-called First Law of Behavior Genetics: All human behavioral traits are heritable.” Turkheimer coined this and two further “laws” to point up ironies in the way behavior genetics was being…
Feasibility and Uncertainty in Behavior Genetics for the Nonhuman Primate
M. J. Adams International Journal of Primatology February 2014, Volume 35, Issue 1, pp 156-168 doi: 10.1007/s10764-013-9722-8
Nonhuman primates are good species to study for understand the genetic underpinnings of behavior, especially because their behaviors are so similar to our. One reason that primates are good to study is because they are individually identifiable and we tend to know which individuals are related (or we can discover this using genotyping).
However, studying primates offers several challenges. The main one is that when studying nonhuman primates the sample sizes (dozens or at most hundreds) are much smaller than what is typical in studies of humans (hundreds to tens of thousands). This small sample size diminishes statistical power and limits the types of questions that can be investigated.
I conducted some simulations to see just how gloomy the prospects are. I found that statistical power can be increased slightly by multiple measurements of each individual, something that is feasible since primates are long-lived.
Abstract
The analysis of phenotypic covariances among genetically related individuals is the basis for estimations of genetic and phenotypic effects on phenotypes. Beyond heritability, there are several other estimates that can be made with behavior genetic models of interest to primatologists. Some of these estimates are feasible with primate samples because they take advantage of the types of relatives available to compare in primate species and because most behaviors are expressed orders of magnitude more often and in a greater variety of contexts than morphological or life-history traits. The hypotheses that can be tested with these estimates are contrasted with hypotheses that will be difficult to achieve in primates because of sample size limitations. Feasible comparisons include the proportion of variance from interaction effects, the variation of genetic effects across environments, and the genetics of growth and development. Simulation shows that uncertainty of genetic parameters can be reduced by sampling each individual more than once. Because sample sizes are likely to remain relatively small in most primate behavior genetics, expressing uncertainty in parameter estimates is needed to move our inferences forward.
