In finitely repeated prisoner dilemma games, two-person teams start out with significantly less cooperation than individuals, consistent with results reported in the social psychology literature. However, safety concerns quickly give way to teams cooperating significantly more than individuals....

We examine behavior in one-shot appropriation games with deterministic and probabilistic degradation externalities, where the marginal net benefit from appropriation is endogenous, dependent on individuals' expectations of group appropriation. The experimental design involves a menu of games...