The effect of conflict history on cooperation within and between groups: Evidence from a laboratory experiment

We study cooperation within and between groups in the laboratory, comparing treatments in which two groups have previously been in conflict with one another, in conflict with a different group, or not previously exposed to conflict. We model conflict using an inter-group Tullock contest, and measure its effects upon cooperation using a multi-level public good game. We find that conflict increases cooperation within groups, while decreasing cooperation between groups. Moreover, we find that an increase in the gains from cooperation only increases cooperation between groups when the two groups have not previously interacted.