Studies on the social behavior and cooperation decisions of individuals within and between different ethnic or cultural groups have gained increasing importance in economic sciences, especially in the field of behavioral economics. Axelrod and Hammond (2006) developed an agent-based simulation...

Imperfect private monitoring in an infinitely repeated discounted Prisoner's Dilemma played on a communication network is studied. Players observe their direct neighbors' behavior only, but communicate strategically the repeated game's history throughout the network. The delay in receiving this...

We study prisoner's dilemmas played in continuous time with flow payoffs over 60 seconds. In most cases, the median rate of mutual cooperation rises to 90% or more. Control sessions with 8-time repeated matchings achieve less than half as much cooperation, and cooperation rates approach zero in...

Often in cooperative situations, many aspects of the decision-making environment are uncertain. We investigate how cooperation is shaped by the way information about risk is presented (from description or from experience) and by differences in risky environments. Drawing on research from risky...

Agents interacting on a body of water choose between technologies to catch fish. One is harmless to the resource, as it allows full recovery; the other yields high immediate catches, but low(er) future catches. Strategic interaction in one "objective" resource game may induce "subjective" games...

Repeated games tend to have large sets of equilibria. We also know that in the repeated prisoners dilemma there is a profusion of neutrally stable strategies, but no strategy that is evolutionarily stable. This paper shows that for all of these neutrally stable strategies there is a stepping...

This paper analyzes the dynamic stability of moral codes in a two population trust game. Guided by a moral code, members of one population, the Trustors, are willing to punish members of the other population, the Trustees, who defect. Under replicator dynamics, adherence to the moral code has...

In evolutionary models of indirect reciprocity, reputation mechanisms can stabilize cooperation even in severe cooperation problems like the prisoner's dilemma. Under certain circumstances, conditionally cooperative strategies, which cooperate iff their partner has a good reputation, cannot be...

Charles Darwin (1874) stated that "women are less selfish but men are more competitive". Very recent papers (Eckel & Grossman, 1998, 2001 or Andreoni and Vesterlund 2001, among others) have shown the relevance of gender in altruism in both ultimatum and dictator games. In this paper we analyze...