Schools matter, but they don’t make a difference

From Is Sociogenomics Racist? by Toby Young, a book review of Blueprint: How DNA Makes Us Who We Are by Robert Plomin. Sociogenomics, closely related to sociobiology, is

the field of research that examines why and how different social factors and processes (e.g., social stress, conflict, isolation, attachment, etc.) affect the activity of the genome.

Though that is not quite right. It is not just the affect of social factors on the genome but also the affect of the genome on social factors.

It is a relatively recent field and nothing can be concluded with great certainty but I have to acknowledge that the weight of evidence has been trending towards the sociogenomicists for some time.

The field is controversial on two fronts. For people (such as myself) for whom free will is an integral element of their world view, a naive interpretation of sociogenomics suggests that there is little true free will. We are all subject to our genome and it is easy to slip into an interpretation that genomes are deterministic. We are our genes and there is little or nothing we can do about it. Genes are deterministic is the sorry conclusion.

For people for whom postmodernism and critical theory (and in particular critical race theory) are an important element of their world view, a naive interpretation of sociogenomics suggests that there is a racial hierarchy of ability (especially in terms of IQ) and that sociogenomics as a field threatens to revive eugenics and racism.

Both are fair concerns but it is important that the implications are not inherent in the research of sociogenomics itself. They are concerns about interpretation and application. In other words, facts are facts, independent of how you choose to interpret those facts and what you choose to do about them.

Young tackles both these issues. On determinism (the gentleman Comfort referenced is another reviewer who has raised such concerns about Plomin's work):

It should be obvious from the above that polygenic scores are probabilistic not deterministic, but in case that isn’t clear Plomin belabours the point: “Genetic influences are probabilistic propensities, not predetermined programming” (p.43); “Polygenic scores are useful for individual prediction only as long as we keep in mind that the prediction is probabilistic, not a certainty” (p.145); “Polygenic scores will always be probabilistic, not deterministic, because their ceiling is heritability, which is usually about 50 per cent” (p.150); “It is worth reiterating the mantra that polygenic scores are inherently probabilistic, not deterministic” (p.151); “It is important that parents are not fatalistic about their children, because polygenic scores are probabilistic not deterministic” (p.154); etc. How Comfort can accuse Plomin of “genetic determinism,” or of believing that “genes alone control human nature,” given his constant repetition of this “mantra,” is a mystery.

What seems to have convinced Comfort that Blueprint is “insidious” is Plomin’s claim that “genetics is the main systematic force in life.” What Plomin means by this is that while most human traits are no more than 50 percent heritable—that is to say, no more than half the phenotypic variance is linked to genetic variance—the salient aspects of the environment are not those experiences we share with our siblings, such as our parents’ socio-economic status, their approach to parenting, the neighborhood we’re brought up in or the schools we go to. Plomin has assembled a mass of research evidence, based on twin, adoption and family studies, showing just how little effect the shared environment has. “The astonishing implication from this research is that we would be just as similar to our parents and our siblings even if we had been adopted apart at birth and reared in different families,” he writes in Chapter Seven (‘Why children raised in the same family are so different’).1 In his most recent research, he has incorporated polygenic scores into the study designs. For instance, he worked on a study involving a U.K.-representative sample of 4,814 students that showed the type of school British children attend accounts for less than one percent of the variance in their exam results once you control for general cognitive ability, prior attainment, parental socio-economic status and polygenic score for EduYears. (Full disclosure: I was one of the co-authors of that study.)

Families and schools are what we think of as “nurture” and one interpretation of Blueprint is to see it as a salvo in the ongoing nature-nurture debate—a devastating, war-winning salvo. But it doesn’t follow that Plomin thinks the environment, as distinct from nurture, has no effect on the way people turn out. The environmental inputs that matter most, according to him, are what he calls our “non-shared” experiences—“unsystematic, idiosyncratic, or serendipitous events,” often mediated by our genetic predispositions. So when Plomin says genetics is by far the greatest systematic force in making us who we are, he isn’t saying the environment has no effect. It’s just that the environmental inputs that do have an impact are, for the most part, unsystematic.

“We now know that DNA differences are the major systematic source of psychological differences between us,” he writes in the ‘Prologue.’ “Environmental effects are important but what we have learned in recent years is that they are mostly random—unsystematic and unstable—which means that we cannot do much about them.”

This has far-reaching implications, many of which threaten to lay waste to vast areas of intellectual endeavor. Freudian psychoanalysis, for instance, is clearly bunk, as is most child psychology (unless it’s Judith Rich Harris patiently explaining why parents have little effect on the way children turn out). Parenting manuals? Not worth the paper they’re printed on.

What about education reform? That’s a tough one for me because I’ve devoted nearly a fifth of my life to trying to improve English public education, including co-founding four schools. But the implication of Plomin’s research is that it’s extremely hard, not to say impossible, for governmental agencies and charitable bodies to design systematic interventions, whether in early childhood or adolescence, that will reduce the attainment gap—which may explain why nearly all such attempts have failed. In fact, if you drive up standards in under-performing schools, the effect would be to increase the overall variation in attainment due to genes since if you equalize the environment you will increase the influence of genes, making exam results more, not less, heritable.

The most generous thing Plomin can bring himself to say about schools is that they matter, but they don’t make a difference. Don’t make a difference. There go the last 10 years of my life—poof. To paraphrase another scientist called Robert, Plomin is like Vishnu, a destroyer of worlds.

I think Young is making an important point with which I agree, but it is a guarded solace. Polygenic scores are indeed only probabilistic; they are not deterministic. That said, they are far more predictive than I would have wished from a normative perspective.