Time-consuming and costly religious rituals pose a puzzle for economists committed to rational choice theories of human 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...

The in-group-out-group bias is among the most well documented and widely observed phenomenon in the social sciences. Despite its role in hiring decisions and job discrimination, negotiations, and conflict and competition between groups, economists have heretofore ignored the in- group-out-group...

Unlike individuals living in capitalist economies, members of collective societies depend on mutual cooperation to achieve their economic goals. We study the cooperative behavior of one of the most successful and best-known modern collective societies, the Israeli kibbutz. The facts that kibbutz...