Multigame Contact : A Double-Edged Sword for Cooperation

We study the effect of multigame contact on cooperation. In our experimental setup, each subject plays a pair of indefinitely repeated prisoner’s dilemmas. Multigame contact is present if a subject plays both games with a single partner, and it is absent if a subject plays each of the two games with a different partner. In contrast to the theoretical prediction, we find no evidence of multigame contact increasing overall cooperation rates. Nonetheless, multigame contact systematically affects behavior and outcomes, acting like a double-edged sword, in the sense that subjects link decisions across games and, consequently, periods of mutual cooperation and defection in both games become more likely, while periods of mutual cooperation in a single game become less likely