Risk and Temptation: A Meta Study on Prisoner's Dilemma Games

This paper reports the results of a meta-study of 96 prisoner's dilemma studies comprising more than 3500 participants. We disentangle the role of “risk” (to cooperate unilaterally) and “temptation” (to defect against a cooperator) and find that (i) an index of risk best explains the variation in cooperation rates across one-shot games, while (ii) an index of temptation best explains the variation in finitely repeated games. Risk and temptation indices also affect gender comparisons. Women are more cooperative than the average man if risk is low and less cooperative if risk is high. There are no gender differences on average.