What is ‘genetic nurture’ and how does it impact educational achievement?

The phrase “Look down your nose” comes from a time when aristocrats were taller than commoners due to their superior nutrition. European elites would literally look down on their inferiors. So it shouldn’t be hard to imagine the shock 19th-century aristocrats experienced, across the Atlantic, encountering well-fed American laborers, artisans, and farmers, who would look at their betters eye-to-eye. In societies where nutrition varies a great deal and correlates with socioeconomic status, like in England during the Industrial Revolution, tall people tend to be of higher socioeconomic status.

Genes play a role, too, of course. Height, as researchers say, is 80 percent “heritable.” Heritability is the variation of a trait in a population—in this case, height—that you can attribute to variation in genes. When height’s heritability, a summary of innumerable complex biological pathways that lay down bone, drops below 80 percent, socioeconomic heritability increases. The elites weren’t taller because of their genes—the commoners were just shorter out of deprivation. The outcomes of this interplay between our genes and our environments, what many refer to as the consequences of nature versus nurture, is being more and more precisely traced and quantified using classical and modern genomic methods. Even for the seemingly more abstract traits that we really care about.

Take educational attainment, or how much schooling a person has (primary, secondary, etc). It’s a common metric used in social genomics, a field that looks at the relationship between genes and individual and societal outcomes. Compared to height, educational attainment has a more complex set of layers mediating its expression. There’s the raw computational power your brain has. Your personality (how conscientious are you?) As well as the myriad social, political, and cultural forces which buffet the choices you make in terms of when and if to obtain further education. Interestingly, the genes that shape how educated you eventually become don’t necessarily have to be passed on to you.

A paper, published in the American Journal of Human Genetics, highlights the fact that genes your parents didn’t transmit to you still matter—the phenomenon known as  “genetic nurture.” A team of researchers based in the United Kingdom conducted a systematic review and meta-analysis of 12 studies with nearly 40,000 parent-offspring comparisons. The genetic nurture effect for years of education, they found, is about 50 percent of the value of direct genetic effects. “Empirical studies,” they write, “have indicated that genetic nurture effects are particularly relevant to the intergenerational transmission of risk for child educational outcomes, which are, in turn, associated with major psychological and health milestones throughout the life course.” Genetic nurture is clearly not a factor you can ignore.

How does it work? Some parents may have personalities that have them prioritizing the short-term over the long-term. Rather than investing in their offspring’s educational outcome, by investing in a college fund, say, they may prefer spending the money on vacations to Europe, which have a great deal of short-term utility. The child may have somewhat different preferences, but this would be irrelevant, as these sorts of decisions are usually made by parents. The same is true in the converse situation, where parents make decisions that would increase the likelihood of their offspring going to college. This is a situation where the offspring may not have inherited the gene (or cluster of genes) that gives their parents the long-term vision, but they themselves benefit from that disposition.