ABSTRACT
Social dilemmas are collective situations in which egoistic incentives yield individually dominating strategies that converge on deficient equilibria—that is, on outcomes that are less preferred by the choosers than are alternative outcomes. (The best-known example is the two-person prisoner's dilemma.) The widespread existence of such situations in contexts of interacting individuals provides normative and descriptive challenges to both classical (Western) economic/political theory and to evolutionary theory based on sociobiological assumptions. The normative challenge arises because both theories maintain that beneficent consequences (e.g., economic growth and evolutionary change) follow from responding wholly to egoistic incentives. The descriptive challenge arises because people (and other organisms) often refrain from choosing what appear to be dominating strategies in social dilemma contexts, instead opting for strategies that have more benign collective consequences.
