In defense of behavior genetics

Stuart Ritchie, the author of Intelligence: All That Matters and Science Fictions: How Fraud, Bias, Negligence, and Hype Undermine the Search for Truth, has written a trenchant critique of The New York Review of Books critique of The Genetic Lottery: Why DNA Matters for Social Equality at his Substack. Titled, Scientific Nihilism: A review of a review of Kathryn Paige Harden’s “The Genetic Lottery”, Ritchie goes into a lot of detail on why he disagrees with the critique. In the old blogosphere, we would call this a “fisking.”

Probably the most immediate issue I had with the review, and critiques of the science in The Genetic Lottery, is that the skepticism of the robustness of the inferences from the methods used in behavior genetics is so often lacking when it comes to the rest of the social sciences, in particular those areas that are normatively aligned with the views of the critics. For example, in the 1970’s some of the harshest critics of behavior genetics and later sociobiology were Marxists. Marxism of course purports to be scientific and based on a particular model of the universe. But the harsh skepticism that these Marxist scientists applied to the behavioral sciences that might utilize genetics they seem to have no use for in their own personal commitments.

Interestingly, Ritchie highlights something I missed, a Q & A with the co-authors of the review, where the historian of science Jessica Riskin says the following:

JR: I’m writing a book about the history of evolutionary theory focusing on the life and career of the French naturalist Jean-Baptiste Lamarck, in which I’ll follow the fortunes of Lamarck’s science from his lifetime up to the present. His ideas were foundational to modern biology—in fact, he coined the term “biology” in 1802, defining the science of life as a discrete field, and he also proposed the first theory of species change, or what we now call evolution. The emblem of Lamarckism became the giraffe, who, in stretching to reach high branches, lengthened its neck and forelegs by tiny amounts; these incremental changes, Lamarck proposed, added together over many generations, produced the giraffe’s distinctive form. Lamarck’s theory languished in exile for over a century, from roughly the 1880s until the 1990s, when the possibility that organisms might transform themselves heritably began re-entering mainstream biology in areas such as epigenetics.

Inter-generational heritability of epigenetic marks is a controversial area. It isn’t pseudo-science, but its validity seems to be tenuous in most cases, and most people who work in epigenetics don’t accept that it occurs in humans despite a paper or two that suggests that it does (I know this because I ask them this in private to get their candid view). The conflation of epigenetics as a pretty standard part of molecular genetic processes with what is basically neo-Lamcarkianism has made it so that many epigeneticists don’t even want to define themselves as such. Riskin’s allusion to the inter-generational heritability of epigenetic forces is certainly eyebrow-raising and makes me wonder at the variation in her epistemological standards…

Finally, Stuart Ritchie is a friend. You should support his Substack with your money if you can afford it. He believes the truth is important.

The twilight of American behavior genetics

Many people, including some prominent scientists, have emailed me about the review of K. Paige Harden’s book The Genetic Lottery in The New York Review of BooksWhy Biology Is Not Destiny – In The Genetic Lottery, Kathryn Harden disguises her radically subjective view of biological essentialism as an objective fact. It’s a pretty intense review. I thought it was mostly unfair, but even I winced at the punches that it got in. Give the devil his due?

There are two authors, M.W. Feldman and Jessica Riskin. I don’t know Riskin, but Feldman is an extremely eminent population geneticist whose influence is felt in others fields. He was an early founder of the field of cultural evolution, writing Cultural Transmission and Evolution with L. L. Cavalli-Sforza. From what I know, Peter Richerson attended classes on the topic taught by Feldman in the 1980s, and Richerson was Robert Boyd’s advisor, who was Joe Henrich’s advisor.

Indirectly Feldman is arguably the father of much of contemporary cultural evolution and cliodynamics.

As for what’s unfair in the piece, I think the below passage illustrates the method well:

“This polygenic index will be normally distributed,” Harden continues, now disguising an assumption—that there are intrinsic cognitive and personality traits whose distribution in a population follows a bell-shaped curve, a founding axiom of eugenics—as an objective fact.

Eugenics aimed to be an applied branch of hereditary science, and before the emergence of Mendelism, it was driven by ‘biometric’ thinking about continuous quantitative traits (though Francis Galton himself believed in “sports” and other noncontinuous changes). So the connection between eugenics and the normal distribution does exist…but the fact is that the normal (Gaussian) distribution is ubiquitous in science, and emerges out of the central limit theorem. Anyone with a cursory background in quantitative sciences won’t really associate the normal distribution with eugenics. How exactly was Harden going to write a book on behavior genetics without mentioning the normal distribution?

There is a lot of that sort of guilt-by-association and verbal sleight of hand. I think most fair-minded scientists will see what they did, but that’s not how the typical reader of The New York Review of Books will read the piece. Rather, they’ll see one hard-hitting salvo after another from two Stanford academics, one of whom is one of the most accomplished population geneticists of our day. How are they going to know about the ubiquity of the normal distribution and its centrality to much of modern statistics? Instead, most readers will experience an incredibly erudite and magnificent demolition of The Genetic Lottery and its presuppositions and implications.

Just to show you what I mean, let’s look at this passage. I’m going to add numbers that will help in the exegesis:

Harden condemns Jensen’s racism and rejects his assertion that social interventions are futile, but she doesn’t question his basic claim that genetic differences produce an [1] innate hierarchy of scholastic achievement. She also doesn’t acknowledge his dependence on fraudulent data from a 1966 paper by the English psychologist and geneticist Cyril Burt purporting to compare identical twins raised together and apart [2]. And nowhere does she cite the Princeton psychologist Leon Kamin’s 1974 devastating debunking of Jensen and Burt or engage with the critical problems Kamin raised there regarding twin studies in general, because of the impossibility of isolating genetic factors from environmental ones [3].

First, [1], there’s nowhere in the book that I recall Harden talking about “innate hierarchy.” One can see why Feldman and Riskin use this term, but the concept is repeated so often in the review that I believe most readers will believe this is exactly what Harden talked about in the book. No, it’s their interpretation and imputation. But repeated enough the allusive imputation becomes the literal fact.

As for [2], the Cyril Burt controversy continues down to the last I checked. He may have committed fraud, or he may not have. Feldman and Riskin take it as a given that the initial accusations of fraud were correct and not disputed. The reader won’t know the controversy about the controversy. As for [3], the reader will be unaware that in the 1970’s Kamin actually floated the position that the heritability of intelligence was ~0, severely undermining his credibility as a sagacious researcher. Second, the implication that there is an impossibility of isolating genetic factors from environmental ones is coherent in light of all the complexities of…complex traits. But this applies to many behavioral and nonbehavioral traits that are polygenic. Should we entertain the possibility that we can’t adduce the genetic aspect of schizophrenia due to philosophical quibbles about causality? (it’s very heritable)

If you want to know more about behavior genetics and genomics, I recommend this interview I did with James Lee, or this one from the fall with Alexander Young. As for Harden and The Genetic Lottery, I’m glum about the prospects for any project like this in this country. Though Harden is a tenured academic and comes out of a pretty good lineage (her advisor is Eric Turkheimer), ever since the bizarre piece in The New Yorker her reputation in many biological academic circles has taken a hit. From everything I know, she is sincere, earnest and a legitimate political progressive/liberal. But you wouldn’t know that from what some people say, and the lie repeated often enough becomes the truth. In 2006 I interviewed the famed population geneticist James F. Crow, and he stated that he felt “strongly that we should not discourage a line of research because someone might not like a possible outcome.” Crow died in 2012 at the age of 96, and from what I can see this sort of stance is mostly held by older academics.

A different wind blows in the future. Harden has tenure, and a band of her fellow travelers will continue to exist in American academia, but more and more they will be pariahs. Why? I’m not progressive so that’s beyond my pay grade. But there are other countries out there, so there will be places this sort of research continues.

The truth is what it is. No matter what the flock says.

Addendum: Bert Hölldobler, a long-time collaborator of E. O. Wilson has written a defense of him. Richard Lewontin was a great population geneticist, but I think his biggest impact will turn out to be the style of intellectual pugilism he promoted. It’s normative now among many younger academics. Here’s a section that jumped out at me:

It was a point that Dick Lewontin himself acknowledged when he showed up at my office the next day, apparently eager to soften what he had said. Although I respected Lewontin as a scientist and colleague at Harvard, I did not appreciate his ideologically driven “sand box Marxism.” When I asked why he so blithely distorted some of Ed’s writings he responded: “Bert, you do not understand, it is a political battle in the United States. All means are justified to win this battle.”…

Genetic correlation between friends

There is an interesting, and sexy, line of research which suggests that people who are non-related friends are genetically more similar than you’d expect. For years people have been telling me privately that this is not likely to be robust, and probably just really really subtle structure (friends of mine). But most of these were private gripes. Now a group has written a preprint outlining the basis from skepticism, No evidence for social genetic effects or genetic similarity among friends beyond that due to population stratification: a reappraisal of Domingue et al (2018):

Using data from 5,500 adolescents from the National Longitudinal Study of Adolescent to Adult Health, Domingue et al. (2018) claimed to show that friends are genetically more similar to one another than randomly selected peers, beyond the confounding effects of population stratification by ancestry. The authors also claimed to show ‘social-genetic’ effects, whereby individuals’ educational attainment (EA) is influenced by their friends’ genes. Neither claim is justified by the data. Mathematically we show that 1) although similarity at causal variants is expected under assortment, the genome-wide relationship between friends (and similarly between mates) is extremely small (an effect that could be explained by subtle population stratification) and 2) significant association between individuals’ EA and their friends’ polygenic score for EA is expected under homophily with no socio-genetic effects.

Almost no one is a genetic determinist except in your Communist imagination

Next summer I’m going to be giving a talk at the ISIR meeting. I’m a little bemused about this since, to be honest, I don’t talk much about behavior genetics and intelligence anymore.

Until August of 1998, I had rather conventional views for someone of my education and social background on psychometrics. Then I read Chris Chabris’ article in Commentary. From that, I began to conclude the “orthodoxy” that was presented in the elite media really wasn’t representative of what was going on in the field of psychometrics. It’s kind of like thinking that you get a balanced view of the Arab-Israeli conflict from reading Commentary.

Over the next few years, I read some books, review papers, and updated my views. Every few years I read a book or checked out a paper to see if anything had changed…and usually not to my eye as someone who is not in the field. About a decade ago I read What Is Intelligence?: Beyond the Flynn Effect. More recently I read Stuart Ritchie’s Intelligence and Richard Haier’s The Neuroscience of Intelligence. And other things here and there.

I’ll be reviewing Blueprint: How DNA Makes Us Who We Are, but I do wonder if it’s nothing more than an incremental improvement upon The Nurture Assumption: Why Children Turn Out the Way They Do.

Incrementalism isn’t a problem. I am a big fan of genomics. But its impact has been variable. And frankly in some fields less than you might think. I don’t believe it has changed our understanding of evolutionary process qualitatively (rather, it has allowed a finer-grained resolution to certain arguments around particular hypotheses). Educational attainment 3 is great. But does it change how heritable I think intelligence is in a qualitative sense? Not really. We already knew it was a heritable trait, and we’ve known it for a long time.

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Applying intelligence to genes for intelligence

Carl Zimmer has an excellent write up on the new new Nature study of the variants associated with IQ, In ‘Enormous Success,’ Scientists Tie 52 Genes to Human Intelligence.

The issue with intelligence is that it’s a highly polygenic trait for which measurement is not always trivial. You need really large sample sizes. It’s about ten times less tractable than height as a quantitative trait. There are still many arguments about its genetic nature (though a majority position that it’s not rare variants of large effect seems to be emerging).

But all in good time.

Science is divided into many different fiefdoms, and people don’t always talk to each other. For example I know a fair number of population genomicists, and I know behavior geneticists who utilize quantitative genomic methods. The two are distinct and disparate groups. But the logic of cheap sequencing and big data is impacting both fields.

Unfortunately when you talk to population genomicists many are not familiar much with psychology, let alone psychometrics. When it comes to the behavior geneticists many come out of psychology backgrounds, so they are not conversant in aspects of genetic theory which harbor no utility for their tasks at hand. This leads to all sorts of problems, especially when journalists go to get comments from researchers who are really opining out of domain.

Some writers, such as Carl Zimmer, are very punctilious about the details. Getting things right. But we have to be cautious, because many journalists prefer a truth-themed story to the truth retold in a story format. And, some journalists are basically propagandists.

Over the next five years you will see many “gene and IQ” studies come out, with progressively greater and greater power. Read the write-ups in The New York TimesScience, and Nature. But to my many readers with technical skills this is what you should really do:

  1. pull down the data.
  2. re-analyze it.

My plain words are this: do not trust, and always verify.

I’m a big fan of people educating themselves on topics which they have opinions on (see: population genetics). If intelligence is of some interest to you, you should read some things. Arthur Jensen’s classic The g Factor: The Science of Mental Ability can be quite spendy (though used copies less so). But Stuart Ritchie’s Intelligence: All That Matters and Richard Haier’s The Neuroscience of Intelligence are both good, and cheaper and shorter. They hit all the basics which educated people should know if they want to talk about the topic of intelligence in an analytical way.