The Dark Triad and framing effects predict selfish behavior in a one-shot Prisoner's Dilemma.

What causes us to display selfish behaviors? We explored the extent to which Dark Triad traits (sub-clinical psychopathy, narcissism, and Machiavellianism) support a selfish behavioral strategy. We related performance on a hypothetical Prisoner's Dilemma (an economic game that simulates a two-person social dilemma) to participants' (N = 1400) Dark Triad scores. Because contextual factors also impact selfish behaviors, we tested how framing (gain vs. loss; and social vs. nonsocial) shaped performance in the Prisoner's Dilemma. Participants with high Dark Triad scores were more likely to behave selfishly in the Prisoner's Dilemma. Participants were also most likely to betray their partner in loss-framed and non-socially framed contexts. These effects did not interact with Dark Triad scores. Our data are consistent with the view that seemingly negative personality traits (like those associated with the Dark Triad traits) that persist in the population may serve as evolutionarily adaptive behavioral strategies.