Group cooperation under uncertainty

Previous research has shown an 'interindividual-inter-group discontinuity effect': inter-group interactions generally lead to less cooperative outcomes than interindividual interactions. In this dissertation, I replicate the discontinuity effect in the deterministic prisoner's dilemma, but find that groups are more cooperative than individuals in a stochastic version of the game.;Three major factors that underlie the usual discontinuity effect, were reduced in the stochastic environment: greed, fear, and persuasion power. Two group mechanisms are proposed to explain the reversed discontinuity effect: the motivation to avoid guilt and blame when making decisions that affect others' welfare, and the social pressure to conform to certain norms when one is in a group setting. Follow-up studies reject the social pressure mechanism, but confirm that guilt aversion and blame avoidance drive groups to be more risk concerned than individuals and more likely to invest to reduce risks when uncertainty is present. There is also evidence that uncertainty reduces inter-group distrust that usually exists in group interactions, and may even increases inter-group trust to be higher than inter-individual trust.