Evolutionary theory reveals that punishment is effective in promoting cooperation and maintaining social norms …

organized before some of the games was used as an additional control. Our results show that the degree of cooperation is rather …

provide a zero return to their investors, even when they know that their investors had no role in imposing the threat. Our …

behavior. We propose that religious rituals promote in-group trust and cooperation that help to overcome collective …-action problems. We test this hypothesis on communal societies for whom mutual cooperation is a matter of survival. We design field …

. Despite its role in hiring decisions and job discrimination, negotiations, and conflict and competition between groups … societies, the Israeli kibbutz. The facts that kibbutz members have voluntarily chosen their lifestyle of cooperation and … cooperation when paired with anonymous kibbutz members than when paired with city residents. In fact, when paired with city …

provide a zero return to their investors, even when they know that their investors had no role in imposing the threat. Our …

We introduce a class of two-player cooperation games where each player faces a binary decision, enter or exit. These … exiting. When the game is repeated and players' values to entry are private, cooperation admits the form of either taking … optimal symmetric cutoff strategy. These games capture the nature of cooperation in many economic and social situations such …

of those gains. Incentive contracting in these environments does not crowd-out off- equilibrium cooperation, and at high … incentive levels cooperation is crowded in. …