At N.Y.U., Conley kept getting into disagreements with geneticists, arguing that their methods were dangerously naïve. It seemed to him implausible that studying only twins — the gold standard of genetics research — was enough to teach us the difference between nature and nurture. But over time, he decided that it wasn’t enough to just argue. Conley is an academic, and even within that tortured group he is something of a masochist. At that time he was a tenured professor, the kind of gig most people see as the endgame of an academic career, and yet he decided to go back and grind out another Ph.D., this time in genetics. He went into his program believing that our social environment is largely the cause of our outcomes, and that biology is usually the dependent variable. By the end of his time, he says, the causal arrow in his mind had pretty much flipped the other way: “I tried to show for a range of outcomes that the genetic models were overstating the impact of genetics because of their crazy assumptions.” He sighs. “But I ended up showing that they’re right.”
Now he says he’s convinced the benefits of studying polygenic scores are worth the risks. “I still have some queasiness about what can be done with this research, how politically explosive it can be,” he says. “But as someone who wants to drill down into human behavior, I don’t think we can ignore it anymore.”