Toward a (more) parsimonious account of the link between ‘dark’ personality and social decision-making in economic games

There are large individual differences in prosocial vs. antisocial behavior as studied via economic games. Prominent among the personality traits that have been considered as potential correlates are ‘dark’ traits (especially Machiavellianism, Narcissism, Psychopathy, and Sadism). However, although such traits should account for choices in games, the corresponding associations are weak and inconsistent, leading to a state of knowledge that lacks specificity and parsimony. We argue and demonstrate across 10 studies and 8 economic games (total N = 10,474) that a clearer picture emerges once (a) including games that (also) afford the expression of forgiveness (vs. retaliation) and/or (dis)trust and (b) considering the shared vs. unique aspects of dark traits. Specifically, we find that (i) the common core of all dark traits—the dark factor of personality, D—consistently predicts antisocial behavior in all games, (ii) dark traits also (though less strongly) predict antisocial behavior, and (iii) dark traits do so almost entirely due to D. We discuss the theoretical and methodological implications of these findings for the study of individual differences in pro- vs. antisocial behavior in economic games.