Project summary: This project is aimed at understanding the dynamics of cooperation on Israeli secular and religious kibbutzim. We also sought to compare cooperation on the kibbutz with cooperation elsewhere in Israel, and how kibbutz members cooperated with fellow members and non-kibbutz members. Over 1000 common-pool resource experiments designed to measure cooperation were conducted in over 30 kibbutzim and 7 Israeli cities. I have also lived and conducted fieldwork on three kibbutzim in northern Israel.

Funding: Pinhas Sapir Center for Development, University of Connecticut, U.S.-Israel Binational Science Foundation, Ushi Friedman Grant Foundation

Publications:

2019	Sosis, Richard. Do Religions Promote Cooperation? Testing Signaling Theories of Religion, in The Cognitive Science of Religion: A Methodological Introduction to Key Empirical Studies, eds. Jason Slone and William McCorkle, pp 155-162. New York: Bloomsbury Academic Press
2018	Dunbar, Robin and Richard Sosis. Optimizing Human Community Size. Evolution and Human Behavior 39: 106–11.
2007	Ruffle, Bradley and Richard Sosis. Does it Pay to Pray? Costly Ritual and Cooperation. The B.E. Journal of Economic Analysis and Policy 7:1–35 (Article 18).
2006	Ruffle, Bradley and Richard Sosis. Cooperation and the In-Group-Out-Group Bias: A Field Test on Israeli Kibbutz Members and City Residents. Journal of Economic Behavior and Organization 60:147–163.
2004	Sosis, Richard and Bradley Ruffle. Ideology, Religion, and the Evolution of Cooperation: Field Tests on Israeli Kibbutzim. Research in Economic Anthropology 23:89–117.
2004	Sosis, Richard and Bradley Ruffle. On Ritual and Cooperation. Current Anthropology 45:529-531.
2003	Sosis, Richard and Bradley Ruffle. Religious Ritual and Cooperation: Testing for a Relationship on Israeli Religious and Secular Kibbutzim. Current Anthropology 44:713–722.