Psychopathy and Evolution
– by Kristopher Brazil
What kind of characteristics come to mind when you think of a “psychopath?” Callous, cruel, calculating? Ruthless, reckless, remorseless? Daring, dominant, disaffiliated? No doubt, many readers will indicate these characteristics, and likely many others besides, possibly even with terms that have an ancient ring to modern ears that describe conspecifics who might do us harm—“cold-blooded,” “predatory,” “evil.” Despite the poignant descriptors of psychopathy that seem to disqualify it from humanity, evolutionary thinkers have wondered whether its characteristics might reveal an alternative “way of being human” that is a result of selection having formed it over generations and by which it finds itself amongst the variety of adaptive phenotypes available to human nature.
Research on psychopathy and evolutionary psychology, however, have not grown together over the last several decades, which prompted the need for a recent review in Evolution and Human Behavior in which I examined the two fields with a focus on their integration. Three aims of the review were to (1) get precise about the content domain of the phenotype that is proposed to be adaptive (i.e., clinical psychopathy), (2) address lingering assumptions that evolutionary analyses of psychopathy have maintained about the nature of psychopathy that are no longer tenable from contemporary psychopathy research, and (3) document specific hypotheses that stake a claim on how psychopathy might have been selected for its features.
What is Clinical Psychopathy?
Psychopathy is not a single trait—it isn’t a synonym for callousness, impulsivity, or fearlessness, even though it does encompass these traits. Clinically, it is defined by a constellation of multiple trait dimensions falling into domains of Interpersonal (e.g., dominant, manipulative), Affective (e.g., disaffiliated, remorseless), and Behavioral (e.g., disinhibited, risk-taking) functioning. The distinctiveness of clinical psychopathy may be most clearly grasped when we see the multiple features co-occurring within a person. Imagine three hypothetical 21-year-old men—Vincenzo, Markus, and Cassius. Vincenzo is charming and bold and has a great many ambitions to acquire power and influence. To achieve his goals, he sees manipulation of people and things as one useful tactic among many. But Vincenzo is not aggressive nor is he callous; he wants to win and is calculating—taking his time thinking through things and not acting in the moment—but he tries to minimize the harm done to others because it doesn’t “feel right” and it may negatively impact his reputation. He also places enormous pressure on himself to achieve great things to be able to provide for those he cares about. Markus is aggressive and impulsive, easily angered by others and often finds himself in the same old arguments and fights with other men time and time again. Deep down, he is soft-hearted and cares deeply about those closest to him, but he has been known to have angry outbursts even with close family and friends, often followed by feelings of guilt and shame. Cassius enjoys lying to others and pushing people to the edge because he finds it fun and entertaining. He often tries to express sincerity and concern for others to “change things up” or to get something out of them despite “not actually giving a shit about them.” Cassius never backs down from a fight or shouting match with other men and he has a reputation among acquaintances for being the most daring S.O.B. around (e.g., playing Russian roulette for a pack of smokes). He is never seen with family or the same friends, and he is often seen hitting on women—even when he or they are in a relationship.
Although Vincenzo and Markus exhibit some personality characteristics that are included in the broader psychopathy concept—especially interpersonal and behavioral traits, respectively—it is Cassius who exhibits all of the personality characteristics that make up the concept of psychopathy—interpersonal (e.g., insincerity), affective (e.g., disaffiliated), and behavioral (e.g., risk-taking). The evolutionary question is whether people like Cassius who exhibit all characteristics of psychopathy (a rare phenomenon; Lilienfeld et al., 2019) can be said to reflect an adaptive phenotype that has been selected.
Lingering Assumptions About Psychopathy
Evolutionary ideas of psychopathy were first budding in the 1970s and 1980s, so they are not new. But after Robert Hare catalyzed the field with a reliable and valid clinical measure of psychopathy (Hare, 1980, 1991), the field has progressed enormously. Despite progress in psychopathy research, however, several assumptions about psychopathy have held sway in evolutionary circles that have not kept up with contemporary research on it.
There are three assumptions no longer tenable given contemporary advances in psychopathy research. Assumption 1 is that “psychopaths” are a distinct category where someone is either a “psychopath” or not. An overwhelming number of studies now show measures of psychopathy are dimensional, including clinical measures (Hare, 2003). People differ on psychopathy as a matter of degree, not kind; it is not clearly a taxon as is biological sex or a condition like trisomy 21. Assumption 2 is that the structure of psychopathy consists of a core personality factor (Factor 1) and a deviant behavior factor (Factor 2) that might each warrant an evolutionary explanation. Recent conceptual and statistical modeling, however, now show the structure of psychopathy to exist along three separable personality domains (interpersonal, affective, and behavioral) and an antisociality domain more cleanly identifying its link to “deviance” (e.g., early onset antisocial behavior, criminal versatility). Lastly, Assumption 3 is that some psychopaths are genetically determined whereas others are environmentally caused phenocopies. Developmental and behavior genetic research in psychopathy has grown in recent decades, instead showing that all expressions of psychopathy likely involve gene x environment interactions, even in those who appear to have high genetic risk.
What Ancestral Problem Might Psychopathy Function to Solve?
Synthesizing across research on psychopathy from an evolutionary perspective, the review paper identifies six unique hypotheses (not necessarily mutually exclusive) that offer some suggestion about how psychopathy might have been selected for its features over evolutionary time. These are:
- Cheater strategy: social strategy that fills a niche of defecting in social relationships.
- Cheater-hawk strategy: social strategy that combines defection and aggression in social relationships.
- Mating effort strategy (male only): mate competition strategy that obtains access to mates through deception, competing, and appealing to female mate choice.
- Sexual coercion strategy (male only): mate competition strategy to obtain access to mates through using force and doing so at a young age.
- Fast life history strategy: part of an adaptive phenotypic response that speeds up reproduction because of cues to mortality in early life years.
- Conditional strategy: part of an adaptive phenotype response to adverse environments that increase the odds of reproductive viability in that environment.
The six hypotheses can further be granulated into fitting one of two selection pathways that precisely claim how psychopathy might have evolved. First, psychopathy may afford males some reproductive success by exploiting male reproductive tactics of acquiring mates, including through deception, charm, and aggression. Here, psychopathy may have been an adaptive solution to mate competition among males. Cassius exhibits psychopathy because male ancestors who had similar patterns of personality succeeded in acquiring mates and reproducing with them, which he may also be “trying” to do. Second, psychopathy may afford people in general some reproductive success by exploiting others in the population out of their resources and gaining status, thereby increasing their chances of survival and gaining reproductive opportunities. Psychopathy here may have been an adaptive solution to social competition. Cassius exhibits psychopathy because ancestors who had similar patterns of personality succeeded in acquiring resources and status that then enabled them to reproduce, which he may also be “trying” to do. To further examine which of these two—or both or neither—selection pathways might be most plausible, research on the evolution of psychopathy will benefit from adaptationist thinking (Lukaszewski et al., 2020) as well as more cross-pollination between the fields of evolutionary psychology (Buss, 2016) and psychopathy (Patrick, 2018).
References
- Buss, D. M. (Ed.). (2016). The handbook of evolutionary psychology. John Wiley & Sons.
- Hare, R. D. (1980). A research scale for the assessment of psychopathy in criminal populations. Personality and Individual Differences, 1(2), 111–119. https://doi.org/10.1016/0191-8869(80)90028-8
- Hare, R. D. (1991). The Hare Psychopathy Checklist Revised. Multi-Health Systems.
- Hare, R. D. (2003). The Hare Psychopathy Checklist Revised (2nd ed.). Multi-Health Systems.
- Lilienfeld, S. O., Watts, A. L., Murphy, B., Costello, T. H., Bowes, S. M., Smith, S. F., Latzman, R. D., Haslam, N., & Tabb, K. (2019). Personality disorders as emergent interpersonal syndromes: Psychopathic personality as a case example. Journal of Personality Disorders, 33(5), 577–622. https://doi.org/10.1521/pedi.2019.33.5.577
- Lukaszewski, A. W., Lewis, D. M. G., Durkee, P. K., Sell, A. N., Sznycer, D., & Buss, D. M. (2020). An adaptationist framework for personality science. European Journal of Personality, 34(6), 1151–1174. https://doi.org/10.1002/per.2292
- Patrick, C. J. (Ed.). (2018). Handbook of psychopathy (2nd ed.). Guilford.
