We study impersonal exchange, and ask how agents can behave honestly in anonymous transactions without contracts. We analyze repeated anonymous random matching games, where agents observe only their own transactions. Little is known about cooperation in this setting beyond the prisoner's...

We study the role of inter-group differences in the emergence of conflict. In our setting, two groups compete for the right to allocate societys resources, and we allow for costly intergroup mobility. The winning group offers an allocation, that the opposition can either accept, or reject and...