Scientists in Belgrade have found evidence that manipulative and deceitful personality traits allow psychopaths to achieve reproductive success in unpleasant environments.

“Our research team is generally interested in adaptive outcomes of behavior in biological (evolutionary) sense. This means that we conduct our research in the intersection of two scientific fields: behavioral ecology and evolutionary psychology,” explained study author, Janko Međedović of the Institute of Criminological and Sociological Research.

“Psychopathy is an interesting phenomenon in general, because it has detrimental consequences for society and especially for individuals who end up as victims of psychopathic manipulation,” he told PsyPost. “Psychopathy is often considered as a personality disorder, or some kind of mental/behavioral dysfunction. In evolutionary sense, that would mean that natural selection acts against the gene alleles which contribute to psychopathy.”

“However, the existing literature suggest that psychopathy may have adaptive consequences as well, especially in certain environments,” Međedović said. “We tested these contrasted hypotheses. Our criterion measure was the number of children, as a major evolutionary fitness component (the number of offspring you have is directly proportional to the frequency of your genes in the next generation, which makes it the main carrier of evolution).”

The study, which was published in the journal Evolutionary Psychological Science, examined 181 male convicts from two penal institutions in Serbia. The researchers found that inmates who scored higher on a test of psychopathy tended to have more children.

“The obtained findings showed that manipulative and grandiose psychopathy traits were positively related to reproductive success, while affective callousness and coldness was positively related to evolutionary fitness only in individuals who lived in a harsh environment,” Međedović explained. “This means that natural selection may propagate the genes which contribute to these two psychopathy traits.”

The findings suggest that psychopathy could be favored by natural selection in some circumstances.

“We learned something about the evolution of psychopathy,” Međedović told PsyPost. “It may describe adaptive variance in behavior, probably it is an alternative behavioral strategy that may enhance evolutionary fitness, at least under certain conditions (I say ‘alternative’ because the majority of individuals in the population are trustful, cooperative and show reciprocal altruism).”

“Note that when we say adaptive we mean that it could be adaptive for psychopathic individuals – it is still deeply immoral behavior with detrimental consequences for other individuals. But we believe (and this is my subjective belief) that we should not treat psychopathy as a mental illness – something which positively contributes to evolutionary fitness should not be viewed as a psychological dysfunction.”

The study has some limitations.

“The criterion measure is not a lifetime reproduction success, so we must be careful in the interpretation of the results,” Međedović acknowledged. “Furthermore, the research sample was not representative for a population, which limits generalizability of the findings.”

“Still, it is an interesting information which should facilitate further research in the evolutionary explanations of psychopathy. Probably the most important question is: what processes contribute to the maintenance of genetic and phenotypic variance in psychopathy – or simply put, why individuals differ in psychopathy traits in the first place, why some are more, while others are less psychopathic?”

“Our hypothesis is that psychopathy shows evolutionary trade-offs: it may elevate some evolutionary fitness components (e.g. reproductive success) but decrease some other evolutionary fitness components (e.g. longevity or parental investment). If both low and high psychopathy may have adaptive consequences, this may maintain the variance in psychopathy traits,” Međedović added.

The study, “Interpersonal and Affective Psychopathy Traits Can Enhance Human Fitness“, was co-authored by Boban Petrović Jelena Želeskov-Đorić and Maja Savić.