IDEOLOGY, RELIGION, AND THE EVOLUTION OF COOPERATION: FIELD EXPERIMENTS ON ISRAELI KIBBUTZIM

Despite the putative importance of ideological commitments in the evolution of large-scale cooperation among unrelated individuals, evolutionary researchers have yet to examine empirically the relationship between ideology and cooperation. We conduct an experimental game on Israeli kibbutz members to evaluate whether: (1) differences in ideological commitment can explain variation in cooperation within and across kibbutzim; and (2) whether certain types of ideologies are better at promoting cooperation than others. We use the cooperative behavior of Israeli city residents as a baseline and show that members of collectivized kibbutzim are more cooperative than city residents, while members of kibbutzim that have abandoned socialist ideology (privatized kibbutzim) are no more cooperative than city residents. Our results further indicate that among collectivized kibbutzim, members of religious kibbutzim are more cooperative than their secular counterparts. Religious males who engage in thrice-daily communal prayer display the highest levels of cooperation of any subpopulation in our sample. We discuss how the performance of sanctified rituals serves to internalize religious ideological commitment, thus enhancing the ability of religious ideology to motivate cooperative behavior.