The influence of psychopathic traits and strategic harshness on point gain and cooperation rate in the Prisoner's Dilemma

Abstract In a sample of 158 undergraduates, we investigated social cooperation in the fearless dominance (FD) and impulsive antisociality (IA) factors of psychopathy using iterated Prisoner's Dilemma games with eight computer opponents that employed strategies varying in harshness/leniency. We analyzed rates of cooperation during each game, participants' total points gained, and the difference in points earned between participant and opponent (competitive point gain) both in the experiment overall and in subsequent trials after cooperation or defection choices as well as after participant or computer choices. IA correlated with reduced competitive point gain, whereas FD correlated with greater competitive point gains in the very lenient condition but reduced total point gains in the harsh conditions. In subsequent trial analyses, FD correlated with greater competitive point gain in response to participants' own choices. In contrast, after any cooperation on the previous trial, IA correlated positively with cooperation but negatively with competitive point gain.