Did humanity evolve to have psychopaths?
Psychopaths are manipulative, violent, impulsive, and lack empathy — but research suggests that psychopathy may be an evolutionary strategy rather than a disorder.
- It's tempting to think of psychopathy as a kind of aberrant mental condition, but several studies suggest that it may be an evolutionary strategy.
- A study compared the genetic profiles of psychopaths with individuals who were more likely to have children younger and more frequently and found significant overlap.
- This suggests that the qualities that bring about psychopathy are also qualities that encourage more frequent reproduction, making psychopathy an advantageous strategy.
From an evolutionary perspective, it seems odd that we would have psychopaths among our numbers at all. A great deal of what's made humanity a successful species is our social cohesiveness, our empathy toward one another, and our understanding of right and wrong. What benefit could there be for individuals to simply lack these socially binding qualities and to feel a tendency toward violence to boot? The evolutionary role of psychopaths becomes even stranger when you consider the fact that psychopaths are at higher risk for becoming disabled or dying early owing to their impulsivity and reckless behavior.
It's tempting to say that psychopathy is simply the result of a short circuit in the complicated wiring that makes up our brains. However, it may be the case that psychopaths are simply employing a different reproductive strategy than the rest of us. At least, that's what Jorim Tielbeek and colleagues argue.
Looking at the genome
While psychopathy is believed to have some environmental causes, much of what brings it about is genetic. We know that there are certain mutations that encourage psychopathic personalities. Tielbeek and colleagues were curious as to whether these mutations also conferred some other kind of benefit. So, they looked at two large databases containing genotypic data on over 31,000 individuals. A prior study had also uncovered the genetic profiles of individuals who were more likely to have children younger and to have more children overall. By looking at the overlap of these two genetic profiles, the research team was able to see whether there was any correlation between the two sets.
They found that there was, indeed, a fairly significant overlap. The genes associated with having children earlier and more often are also associated with the genes that give psychopaths the characteristics that make them psychopathic, like a lack of empathy.
Why psychopathy exists
It seems counterintuitive, but this finding fits well with what we understand about psychopaths. Previous research has found that psychopaths are often superficially charming, which enables them to attract others in the short term. In the long term, though, this façade crumbles over time. Psychopaths are also prone to greater disinhibition than others, meaning they have problems with impulse control and tend to seek immediate gratification. Combined, these traits would make psychopaths sexually promiscuous, and their disregard for social norms makes them more prone to poaching others' mates or sexual assault, a theory that has been supported by a number of other studies.
But if psychopathy can be a way to have more offspring, why aren't there more psychopaths? After all, Tielbeek and his colleagues' study showed that psychopaths are more likely to have more children, and we know that there is a significant genetic component in psychopathy. Wouldn't the psychopathic gene out-reproduce the non-psychopathic gene?
Why we aren't all psychopaths
One theory is that there's a kind of balancing act going on in the human genome. Highly psychopathic individuals make up about 1 percent of the human population. According to this theory, this number is so low because psychopaths are a kind of social parasite that can only thrive in groups predominantly made up of people who can be taken advantage of; that is, environments made up of moral, empathetic, socially-minded individuals. In groups like these, its easier to take advantage of others' trust to gain resources, like access to sexual partners. If there were too many psychopaths, then this system wouldn't work, and a given social group might become stricter about enforcing group norms. It should be noted that this a difficult theory to test directly.
There's also the idea that the "fast" lifestyles of psychopathic individuals may encourage them to reproduce more frequently, but it doesn't encourage them to invest any of themselves in their offspring's success. Individuals with "slow" lifestyles have fewer children but tend to stick around to make sure their children develop into healthy, competent, and successful adults. The psychopath wouldn't care about that — they demand instant gratification and aren't particularly attracted to the promise of future rewards. In this way, fewer offspring with the psychopathic genome would go on to be in a position to reproduce.
Evolution doesn't have a perspective or an opinion on things. It's a neutral process that selects what works. What these studies show is that, at least when it comes to human evolution, psychopathy is more of a feature than a bug.
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