A new study shows that people with pathological personality traits tend to be more interested in casual sex than long-term relationships.
The findings, published in The Journal of Sex Research, are among the few on the intersection of pathological personalities and sex preferences.
“There is a considerable amount of research on how ‘normal’ personality traits relate to various aspects of sex and relationship preferences, but there is much less on how ostensible pathologies of personality relate to them,” study author Peter Karl Jonason of Western Sydney University told PsyPost.
Jonason and his colleagues approached the study with two goals: to further explore this little-studied area of psychology, and to do so through the lens of evolutionary psychology without making any moral assumptions or judgments.
In the study, the researchers surveyed 702 undergraduates about their personality traits, life history, and sociosexuality. The results showed that people who displayed more pathological personality traits—like detachment, antagonism, disinhibition, and psychoticism—were more interested in casual sex relative to other participants.
“Generally speaking, people with personality pathologies are interested in casual sex more than serious relationships,” Jonason told PsyPost.
“Men are more interested in casual sex than women are and women are more interested in long-term relationships than men are, but the sexes do not differ in the amount prior sexual experiences they have had.”
Jonason said these differences are partially driven by pathology.
“Importantly, these effects (and more) appear to be a function of what is called, someone’s life history speed, which is how they express tradeoffs between long-term, prosocial interests and short-term, selfish interests; a variable of prime importance in modern evolutionary psychology derived from the robust evolutionary biology and behavioral ecology literatures.”
The researchers interpreted the results through life history theory, a theory of biological evolution sometimes employed by evolutionary psychologists that analyzes and “predicts how natural selection should shape the way organisms parcel their resources into making babies,” as professor of biology David Reznick wrote in 2010. The theory argues that our early life experiences influence how we view relationships and sex as we grow older.
From an evolutionary perspective, it would make sense that people who live unpredictable or dangerous childhoods would be drawn to a fast life strategy, which is to say have children earlier in life or have sex with many different partners. The main reason is because they might not expect to live a long life.
In contrast, people who come from a stable upbringing might be less disposed to personality pathologies and more inclined to invest for the future and have children later in life—a slow life strategy.
Still, the results of the study are speculative.
“The most important caveats are related. Because the data is cross-sectional, we cannot know if the order we propose is best. For instance, it is possible, albeit unlikely based on theory, that certain sexual behaviors lead to these pathological personality traits,” Jonason told PsyPost.
“It would be far superior to do some sort of manipulation, but manipulating people into disorders would be unethical and if we could easily change people’s pathologies with some experimental treatment this would be a boon for clinical practice. As such, all we can say is that there are associations here and interpret them through the theoretical lense of life history theory to understand them.”