Psychopathy associated with complex reproductive success trade-offs and harsh childhood environments

A series of recently published studies provides evidence that psychopathy is an adaptation to harsh environments. The new research indicates that psychopathic personality traits have complex trade-offs for reproductive success in humans.

“I was interested in evolutionary ecology of personality in general — stable patterns of behavior differentially expressed among individuals. A mere fact that there are vast differences in behavior between individuals is absolutely fascinating and exciting,” said researcher Janko Međedović of the Institute of Criminological and Sociological Research in Serbia.

“Certainly, individuals differ in their biological (including genetic) characteristics, they live in different environments and experience different things throughout their lifetime — these factors must affect their behavior as well, so they are partially responsible for the existence of individual differences. But is there more than that?”

“We are interested in evolutionary forces which may maintain differences in behavior in a population, both genetic and phenotypic: this is one of major goals of the field of behavioral ecology of human personality or shortened, human personality ecology. Among many personality traits which can be studied from behavioral ecological framework, psychopathy turned out to be a great example of how evolutionary forces may shape behavior,” the author of the studies explained.

“Psychopathy is puzzling and provocative per se: it is a syndrome of behavioral traits consisted of lack of empathy, emotional coldness, ruthless manipulation and deception. So, we asked are there some evolutionary processes which may explain why some people are more psychopathic than others. What evolutionary factors maintain the inter-individual differences in psychopathy?”

In a study published in Personality and Individual Differences, Međedović had 320 parents of psychology undergraduates complete measures of psychopathy, mate seeking behavior, parenting effort, and childhood environmental harshness.

“We found out that psychopathy is positively related to some fitness components (mating effort) but negatively to others (parental effort — care for biological children in this case). This means that highly psychopathic individuals may achieve high fitness by investing in mating (but we should be cautious here — mating cannot be directly translated to reproductive success in modern humans) but low psychopathic individuals may increase fitness by having elevated parental investment,” Međedović told PsyPost.

In other words, participants high in psychopathy were more likely to agree with statements such as “I would like to find a new romantic/sexual partner soon” but less likely to agree with statements such as “I often think about how I could stop bad things from happening to my children.”

The researchers also found a relationship between childhood environmental harshness and psychopathy. The results are in line with another study of 196 female undergraduate students, published in Evolutionary Psychological Science, where Međedović found that dysfunctional family relations and poverty in childhood were linked to psychopathic traits.

“We found that adaptive benefits of psychopathy are more expressed in harsh, depriving and stressful environments — individuals from these environments with elevated psychopathy traits had particularly high mating effort. This suggests that psychopathy may be an adaptation for harsh, hostile and challenging environments. These results, although novel, are in line with previous empirical findings and existing evolutionary theories of psychopathy,” Međedović explained.

“Psychopathy probably evolves in contemporary humans (to be absolutely sure we need to find genetic correlations between psychopathy and fitness). There are evolutionary forces which maintain differences in behavior even in the behavioral traits such as psychopathy.”

“Psychopathy is immoral, frequently antisocial set of traits, and thus, it is detrimental for society. However, it seems that psychopathic individuals may achieve some adaptive benefits in biological sense, especially in certain kind of environments. These benefits maintain psychopathic traits in the human population,” he added.

In yet another study published in Evolutionary Psychological Science, Međedović found that psychopathic traits were positively related to the number of children a person had — but also positively associated with problems in physical health in participants’ offspring. People high in psychopathy also tended to have less grandchildren.

“Although our research is focused on the evolutionary ecology of psychopathy, our findings have societal significance as well. We found that psychopathy is related to diminished care for own children. This is congruent with our other findings of reduced parental investment in psychopathy and even with the positive relations between psychopathy and the presence of physical illness in offspring,” Međedović told PsyPost.

“Apparently, parental psychopathy is related to various negative outcomes in children. This is another motivation for psychologists to work on programs aimed at reducing or preventing psychopathy, but to other services dedicated to child welfare as well.”

But the studies — like all research — include some limitations.

“Some methodological limitations are almost always present in our research and this study is not an exception. The sample, although it had an adequate size, was one of convenience. Hence, it is not representative for a population which buffers generalization of findings. Our designs are mostly cross-sectional, which prevents us from establishing causal relations between the measures we collected,” Međedović explained.

“Finally, I am not completely satisfied with the quality of our measures. This refers particularly to the measure of parental effort: self-report measures are not the best one when you want to capture parental investment.”

“However, we still believe that our findings are valid since the results from our other studies showed that psychopathy was negatively related to parental investment even when it was rated by offspring, not the parents themselves. Nevertheless, we should use more objective information both for parental investment and environmental conditions anytime we can,” Međedović said.

“It is fascinating and exciting to study the contemporary evolution of human behavioral traits. These studies will enrich our knowledge of why there is personality in the first place — more precisely, how individuals use behavior to adapt to ecological conditions and how behavior is diversified in the populations.”

“This line of research is only beginning to develop – this is not an easy task since the phenomena in question are complex and sometimes hard to empirically capture in a scientifically sound manner. Furthermore, human behavioral ecology is an interdisciplinary field par excellence, which imposes another challenge upon the researchers: the task of learning about other fields of science and incorporating them in a research (this is especially hard if you lack resources or funding),” Međedović added.

“However, all these obstacles and challenges make the knowledge which is obtained even more appealing. I believe that this is a promising research program and that we will see many interesting findings in near future.”

The studies were titled: “Harsh environment facilitates psychopathy’s involvement in mating-parenting trade-off“, “Exploring the Links Between Psychopathy and Life History in a Sample of College Females: a Behavioral Ecological Approach“, and “Complex Relations Between Psychopathy and Fitness May Indicate Adaptive Trade-Offs“.