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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.

3 thoughts on “In defense of behavior genetics

  1. Intergenerational epigenetic inheritance is wildly exaggerated, but lifetime epigenetic effects from childhood experience are probably common. The problem isn’t the mechanism. The problem is people making up specific claims about it, usually to push a political agenda. If a giraffe has trouble reaching high branches, what (genetically evolved) switch does this trigger? So many possibilities.

  2. Nice review article on epigenetics (although from 2014 rather old) is at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4020004/

    A skeptical July 2018 paper can be found at https://pubmed.ncbi.nlm.nih.gov/30061690/ with an abstract stating:

    “Transgenerational epigenetic inheritance refers to the transmission of epigenetic information through the germline. While it has been observed in plants, nematodes and fruit flies, its occurrence in mammals-and humans in particular-is the matter of controversial debate, mostly because the study of transgenerational epigenetic inheritance is confounded by genetic, ecological and cultural inheritance. In this comment, I discuss the phenomenon of transgenerational epigenetic inheritance and the difficulty of providing conclusive proof for it in experimental and observational studies.”

    More upbeat from 2019 is this review and meta-analysis https://pubmed.ncbi.nlm.nih.gov/31374565/ which states in part of the abstract: “We found strong evidence supporting the role of DNA methylation patterns, histone modifications and even non-protein-coding RNA in altering the epigenetic composition of individuals and producing stable epigenetic effects that were transmitted from parents to offspring, in both humans and rodent species.”

    I would agree that it is a less important mechanism than many non-experts assume, but it does seem that there is at least some real phenomena out there, and the fact that it is undisputedly common in plants and found in other animals certainly makes the concept less far fetched than it might be otherwise.

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