One of the defining features of an antisocial personality is a lack of care and concern for the wellbeing of others. Intuitively, you’d probably guess that someone with an antisocial personality—known more commonly as a psychopath or sociopath—would be at a disadvantage when it comes to reproducing and passing along their genes. Because who wants to sleep with a psychopath?
As it turns out, this line of reasoning is all wrong: People with antisocial personalities actually seem to have a reproductive advantage over the rest of us, according to a new study led by a research team out of Amsterdam.
Scientists reached this conclusion by performing a complex genetic analysis on more than 31,000 individuals. Specifically, they looked at what’s called the genetic correlation between antisocial traits and reproductive outcomes (namely, age at first birth and total number of children born). In other words, what they were doing here was looking to see how much overlap there is between the genes linked to having an antisocial personality and the genes linked to reproducing early and often.
The results revealed significant genetic overlap, meaning that the genes associated with antisocial traits were correlated with the genes associated with reproducing earlier in life and having more children. Put another way, these findings suggest that whatever genes are responsible for a lack of empathy are the same genes that are responsible for greater reproductive output.
So what’s going on here? One way to make sense of these findings is to consider them in light of previous research, which has found that psychopaths are bigger risk-takers across the board. For instance, they drink more alcohol, use more drugs, and have more sexual partners, among other things.
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This is thought to stem from the fact that psychopaths have lower levels of self-control, which has been demonstrated, in part, by their tendency to favor short-term over long-term gains. For example, when asked if they’d rather have $100 today or $1,000 in a year, psychopaths are the kind of people who aren’t willing to wait for a payout. They want their money (and everything else) now.
The overall pattern we see here is that people with antisocial traits seem to lead a faster life than everyone else—they’re living for today, not tomorrow. In the end, this approach to life seems to confer a reproductive advantage in that the risks psychopaths take lead them to start reproducing earlier and in greater numbers.
These findings can help to explain why a socially undesirable trait like psychopathy hasn’t died out in the human population and, to the contrary, why it persists—and how it could theoretically even increase over time.
Evolution is a funny thing in the sense that the traits that get passed on aren’t necessarily the ones that we deem desirable or moral. As uncomfortable as the thought may be, it's the traits that assist in reproduction—regardless of their social value—that tend to get passed on.
Justin Lehmiller is a research fellow at The Kinsey Institute and author of the blog Sex and Psychology. His latest book is Tell Me What You Want: The Science of Sexual Desire and How It Can Help You Improve Your Sex Life. Follow him on Twitter @JustinLehmiller.