Win-stay, lose-shift strategies in repeated games are based on an aspiration level. Amove is repeated if and only if the outcome, in the previous round, was satisficing in the sense that the payoff was at least as high as the aspiration level. We investigate the conditions under which adaptive...

This report deals with two questions concerning the emergence of cooperative strategies in repeated games. The first part is concerned with the Perfect Folk Theorem and presents a vast class of equilibrium solutions based on Markovian strategies. Simple strategies, called equalizers, are...

The question of cooperation is crucial for understanding Darwinian evolution. Theories of cooperation have been based on kin selection, group selection, and reciprocal altruism. The idea of reciprocal altruism usually involves direct reciprocity: repeated encounters between the same individuals...