Prior interaction, identity, and cooperation in the Inter-group Prisoner's Dilemma

This paper studies theoretically and experimentally how success in prior interaction affects cooperation in the one-shot Inter-group Prisoner's Dilemma (IPD). We develop a model of the IPD that incorporates group-contingent social preferences and bounded rationality to derive conditions under which an increase in pro-social concerns for an out-group will increase cooperation. We then report an experiment that shows the cooperation rate increases from 8 percent in a baseline one-shot IPD to 42 percent when the IPD is preceded by a coordination game played by members of the two groups. A post-experiment survey and chat coding results using a natural language classification game both show that successful prior interaction increases individuals’ concerns for their out-group.