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Our evolved psychology includes some conspicuous paradoxes. For instance, if people generally prefer romantic and social partners who are warm, kind, and other-oriented, then why is the world filled with so many jerks?*

We don’t like jerks. Simply stated, we like nice people. As a result, having a reputation as being nice can lead someone to experience various beneficial outcomes, such as earning promotions at work or winning elections. Being nice, then, is adaptive in both the colloquial and evolutionary senses of the term.1 So how did selfishness become so prevalent in human populations?  

When it comes to human behavior, there is rarely a single approach that is used by all. The evolutionary perspective on social strategies can be understood in terms of strategic pluralism2, the idea that multiple behavioral strategies can evolve alongside one another, leading to adaptive benefits via different paths.

A cutting-edge trend in the field of evolutionary psychology that focuses on one particular social strategy is found at work in the Dark Triad3, three personality traits that, in combination, facilitate self-interested behavioral strategies. These traits include narcissism (an excessive focus on oneself), Machiavellianism (a proclivity to manipulate others for one’s own gain), and psychopathy (a full-out disregard for the feelings of others).

While being a classic nice guy can lead to a positive reputation that corresponds to social success, approaching the social world in a dark, self-interested manner can also lead to various successes. Being a self-interested jerk will, like it or not, lead to advances in one’s own lot. So being selfish, then, can be adaptive.

From an evolutionary perspective, we can understand the fact that people come in both conspicuously altruistic and repulsively self-centered varieties by employing this concept of strategic pluralism.

Recently, the Dark Triad has emerged as something of a game-changer in the study of individual differences. This is partly because measures of the Dark Triad have demonstrated exceptional predictive validity, which exists when a measure of some concept demonstrates the ability to predict various outcomes that are conceptually related to that attribute. Measures of the Dark Triad strongly predict a broad suite of outcomes, suggesting that the Dark Triad is something of a ubiquitous feature of our evolved psychology.

To put a face to this idea, below are several examples of cutting-edge research on the Dark Triad.

Scoring high on measures of the Dark Triad corresponds to being relatively promiscuous in one’s attitudes and behaviors.

Various studies have documented a positive correlation between measures of the Dark Triad and measures of sociosexuality, which roughly corresponds to a proclivity toward promiscuity.4 Behavioral scientists divide sociosexuality into attitudinal, desire-based, and behavioral sub-facets. Someone can score as having relatively promiscuous attitudes (as in being accepting of casual sex), relatively promiscuous fantasies or desires, and/or relatively promiscuous behaviors, such as engaging in one-night stands.

People who score high in the Dark Triad tend to score on high in sociosexuality5. This connection has been found as particularly strong for narcissism. In a study on the sexuality of thousands of young adults from across the globe, David Schmitt of Brunel University and his colleagues found, in addition to scoring high in sociosexuality, narcissists across the globe tend to report relatively high interest in casual sex. They are also relatively likely to engage in mate poaching, meaning they are likely to steal someone else’s partner. Further, relative to others, in most regions, those high in narcissism are relatively likely to engage in HIV-risk-taking behaviors.

Women who score high on the Dark Triad are relatively likely to report having a backup boyfriend.

In a recent study from our lab, graduate student Nicole Wedberg was interested in the factors that predict whether a woman in a long-term dating relationship was likely to have a backup boyfriend (a guy that she keeps waiting in the wings). In this study of over 300 young adult heterosexual women, 20 percent of participants admitted to having a backup boyfriend.6 In addition to a measure of the Dark Triad7, this research included a measure of life history strategy (whether someone utilizes a relatively fast approach to life, focusing on mating relatively early in life with various partners, or a relatively slow approach to life, focusing on mating relatively late in life and a general tendency toward monogamy)8, and a measure of the Big Five trait dimensions of extraversion, emotional stability, open-mindedness, agreeableness, and conscientiousness9. The Dark Triad was the best predictor of whether a woman has a backup boyfriend.

Those who score high on the Dark Triad have a high number of estrangements in their social world.

In another study in our lab, we explored the correlates associated with having a relatively high number of estrangements. That is, we asked more than 300 adults to report how many people in the world are “dead to them,” and we examined which personality traits are most strongly related to this variable10. We found the average number of estrangements to be just under four. That is, most people had about four people in the world whom they described as “dead to them.” We then had participants complete various personality measures, including measures of the Dark Triad. The results were consistent with Nicole Wedberg’s backup-boyfriend research: The Dark Triad emerged as critically and significantly predictive of the number of estrangements someone has in their world. 

Those who score high on the Dark Triad respond very negatively when being insulted, often plotting revenge.

In another study in our lab, we were interested in factors associated with how people respond to being insulted. More than 200 adult participants were presented with various hypothetical scenarios in which a good friend insulted them11. These insults varied across conditions in terms of such factors as how severe they were and whether an apology was given. Outcomes measured included how betrayed they would feel, how likely they would be to forgive, and how likely they would be to plot revenge. In one analysis, we examined how various personality measures predicted these outcomes. The Dark Triad emerged as the strongest dispositional predictor of all of these outcomes. Those high in the Dark Triad reported feeling exceptionally betrayed, they reported that they were unlikely to forgive the transgressor, and they reported that they would plot revenge. 

Bottom Line

When it comes to how we interact with others, there are lots of different approaches out there. From an evolutionary perspective, we can divide these styles into other-oriented (positive) versus self-promotional (dark) approaches. Via dramatically different means, each of these broad social strategies can lead to success in life. Sitting at the junction of self-absorption, manipulativeness, and a genuine disregard for others, the Dark Triad captures the essence of a self-promotional, dark approach to dealing with others.

In a species in which goodness and self-sacrifice are regularly underscored, why are there so many selfish individuals who use their power to step on and intimidate others? More often than not, such individuals show the hallmarks of the Dark Triad. Understanding this behavioral approach in evolutionary perspective gives us a bird's-eye view of the self-promotional, dark approach to life. And this big-picture perspective can go a long way in helping us understand people in our own social worlds who take a dark approach to living.

*Note: Some of the content for this post was developed as part of my brainstorming for a solicited article on the same topic that was published in The Wall Street Journal here.

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1Geher, G., Di Santo, J., & Planke, J. (2019). Social reputation. In T. Shackelford (Ed.), Encyclopedia of Evolutionary Science. New York: Springer.

2Gangestad, S.W., & Simpson, J. A. (2000). The evolution of human mating: Trade-offs and strategic pluralism. Behavioral and Brain Sciences, 23, 573–644.

3Jonason, P. K., Kaufman, S. B., Webster, G. D, & Geher, G. (2013). What lies beneath the Dark Triad Dirty Dozen: Varied relations with the Big Five. Individual Differences Research, 11, 81-90.

4Schmitt, D. P. (2005). Sociosexuality from Argentina to Zimbabwe: A 48-nation study of sex, culture, and strategies of human mating. Behavioral and Brain Sciences, 28, 247-311.

5Schmitt, D. P., …. Geher, G., … Hearns, K. et al. (2017). Narcissism and the Strategic Pursuit of Short-Term Mating: Universal Links across 11 World Regions of the International Sexuality Description Project-2. Psychological Topics, 26, 89-137.

6Wedberg, N. (2016). Partner insurance: Women may have backup romantic partners as a mating strategy. A thesis submitted in partial fulfillment of the Master’s degree in psychology. State University of New York at New Paltz.

7Jonason, P.K., & Webster, G.D. (2010). The Dirty Dozen: A concise measure of the Dark Triad. Psychological Assessment, 22, 420-432

8Figueredo, A. J., Vásquez, G., Brumbach B. H., Sefcek, J. A., Kirsner, B. R., & Jacobs, W.J. (2005). The K-factor: Individual differences in life history strategy. Personality and Individual Differences, 39, 1349- 1360.

9Gosling, S. D., Rentfrow, P. J., & Swann, W. B., Jr. (2003). A Very Brief Measure of the Big Five Personality Domains. Journal of Research in Personality, 37, 504-528.

10, 11Geher, G., & Wedberg, N. A. (2019). Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life. New York: Oxford University Press.