Vernon Smith, Elizabeth Hoffman, and Kevin McCabe University of Arizona SBR-9510919 This proposal is to continue current experimental work designed to discover what factors lead subjects to play more cooperatively and to punish more aggressively than game theory and economic theory predict. The experiments the P.I.s propose to conduct will test a conjecture from evolutionary psychology that humans have evolved a predisposition to learn and use reciprocity in order to help foster cooperation. In certain situations, people behave according to learned rules of thumb that are not necessarily payoff-maximizing. The goal of these experiments is to find the environmental factors that trigger this behavior.
