Is genetics “dark”?

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At the excellent Integrating Genetics and the Social Sciences conference on Thursday and Friday, a late discussion raised an awkward issue: when you say you study the genetics of behaviour, eyebrows get raised. People don’t always like what we do. Now, academics are a quite conformist bunch, and their desire to be liked is particularly unfortunate in the social sciences, where there is always a temptation to tell the paymasters what they want to hear. Still, it is true that doing genetics, especially social science genetics, can feel like juggling with dynamite.

Is there a reason for that? Do the public have reason to fear our results? Is genetics… dark?

It certainly has a dark history. But it is not obvious that the advanced genomics of today has much in common with the eugenics of the 1930s. No sane or influential people are calling for compulsory sterilization programs.[1]

Perhaps, though, genetics could be dark today. One idea that seems to worry many people is: what if geneticists discover genetic differences between ethnic groups? Couldn’t that legitimize discrimination? Leftwingers who fervently oppose this kind of research seem to agree on one thing with neonazis: if we find such genetic differences, well, that would make racism fine.

I am unconvinced. Take a simple analogy. We already know that income and wealth are highly heritable, i.e. that genetic differences exist between rich and poor.[2] This is not scientifically controversial among people who know the literature; Paige Harden, a progressive, has written a book about it; I’d guess that many reasonably informed people now understand it. So what? One reasonable response to the idea that rich and poor people might have different inborn talents is “OK, maybe that well-paid guy deserves his salary”. Another reasonable response, Harden’s one perhaps, is that nobody deserves their genetic luck, so we should do some redistribution to even things out. Calling for the renewal of serfdom is not a reasonable response, and nobody’s done it.

(I dunno. Probably some internet loonbug has done it.)

The analogy goes straight over to any group differences. We might discover them! But if we do, the sensible response will still be “let’s judge individuals as they are, not by their group”. This is just how we respond to environmentally caused differences between groups, which uncontroversially exist.

I’ll take the chance to make my own views clear, because I think honesty is important here. First, we may well discover such genetic differences. In fact, some are known already, like the differences that make people from parts of Africa and India more likely to have sickle cell disease; or the genes that may make Peruvians shorter than others. Second, if we discover them, they’ll be complex, multifaceted, surprising, and interact interestingly with environments; and third, they will ultimately lead us to a richer and deeper appreciation of humanity.

If this happens, and you’ve staked your version of liberalism on the idea that all humans are empirically the same, then that might be awkward for you! (Harden again: “Building a commitment to egalitarianism on our genetic uniformity is building a house on sand.”) And people interpreting intergroup differences as caused by discrimination might have to work harder to prove their case.[3] So yeah, that’ll be disruptive! But this is ultimately an argument between two groups of intellectuals. One side losing isn’t dark, it’s just awkward for them.

So, is genetics dark?

Another candidate is work on contemporary natural selection. Regular readers of my substack will know about our paper on this, and also that it faced some pushback. (Short version: genetics linked to lower earnings are being selected for; effects on inequality might be substantive.) My experience is that on Twitter, people like to blame the modern welfare state for these results. References to the film Idiocracy do get made. Sure, the welfare state could be to blame; that’s a story that could be true. But we don’t see much evidence for it. Indeed, across two-thirds of the twentieth century, even as the welfare state grew considerably, the strength of natural selection seems to stay roughly constant.

There is a darker idea lurking in the wings, which I didn’t think about until I read this paper on random mutations. From the abstract:

Disruptive, damaging ultra-rare variants in highly constrained genes are enriched in individuals with neurodevelopmental disorders. In the general population, this class of variants was associated with a decrease in years of education (YOE)…. Disruptive, damaging ultra-rare variants in highly constrained genes influence the determinants of YOE in the general population.

In other words, rare mutations can lower your chances of making it through school or to university. But “rare” here means that each individual mutation is rare, not that they’re rare collectively. Quite a lot of people have at least one such mutation — about 25% of the sample.[4] Among the most severe mutations which are expressed in the brain, a single mutation costs half a year of education on average.

The dark idea is that natural selection might be like a bicycle: if you don’t keep moving, you fall off. That is, if natural selection doesn’t operate in a population, then deleterious mutations accumulate by chance.

Imagine a society where, if anyone works hard enough, they can make a living and raise a family. That is not a very extreme vision of a welfare state! It is more or less shared between mainstream left and right. Boris Johnson, Theresa May and David Cameron could all get on board with this, and so could Tony Blair or Gordon Brown. But that society might not be sustainable in the long run: its population might get unhealthier, or less intelligent, or less psychologically stable.

Is that dark?

One response is that in the long run, it is no big deal. New gene-editing technologies like CRISPR will put power over our genome back in our hands. We’ve already seen human embryos being selected for polygenic scores; in future, babies’ DNA could be not just checked, but changed. Traditional reproduction was like medieval scholars copying manuscripts, introducing errors all the time into the genetic source; by comparison, the mechanically assisted reproduction of the future could be as accurate as the printing press. That would stop harmful mutations accumulating.

The problem with this solution is that it is not obvious where it ends. Suppose that, by gene-editing, we could get rid of horrible genetic diseases caused by mutations. The ethical arguments for this are strong. But then why not also reduce the chance of more common illnesses too? And why not low intelligence? If heart disease is bad — well, is it fun to be dumb, in our knowledge-based society? These arguments may seem compelling in the near future. If so, we might start to create ever-improved beings, far from traditional, flawed humanity.

A dilemma of human progress, then, is that we might have to choose between remaking ourselves so completely that we are no longer recognizably human; or staying as ourselves, but slowly coming to be the only dysfunctional, unreliable part of a perfectly engineered machine.

Yeah, that seems dark, a little bit.

[1] At least not in the West. China, which has its own history of interest in eugenics, may be different.

[2] For example:
Tambs, Kristian, Jon Martin Sundet, Per Magnus, and Kåre Berg. 1989. “Genetic and Environmental Contributions to the Covariance Between Occupational Status, Educational Attainment, and IQ: A Study of Twins.” Behavior Genetics 19 (2): 209–22. https://​​​​10.1007/​​bf01065905.
Trzaskowski, Maciej, Nicole Harlaar, Rosalind Arden, Eva Krapohl, Kaili Rimfeld, Andrew McMillan, Philip S. Dale, and Robert Plomin. 2014. “Genetic Influence on Family Socioeconomic Status and Childrens Intelligence.” Intelligence 42 (January): 83–88. https://​​​​10.1016/​​j.intell.2013.11.002.
Rimfeld, Kaili, Eva Krapohl, Maciej Trzaskowski, Jonathan R. I. Coleman, Saskia Selzam, Philip S. Dale, Tonu Esko, Andres Metspalu, and Robert Plomin. 2018. “Genetic Influence on Social Outcomes During and After the Soviet Era in Estonia.” Nature Human Behaviour 2 (4): 269–75. https://​​​​10.1038/​​s41562-018-0332-5.

[3] But not always, right? For example, resume experiments will still work. Evidence of differences between groups might change how that discrimination is interpreted — e.g. by pushing towards statistical discrimination rather than taste-based discrimination. But in that regard, genetic differences are no different from environmental differences.

[4] The sample had some cases selected for a previous schizophrenia diagnosis, and some controls. So maybe all of the ultra-rare variants were among the cases. This wasn’t clear from the paper as I read it. It seems that there were also many ultra-rare variants among the Estonian subsample, though, which appears not to have been selected for risk of schizophrenia.