The Effects of Intragroup Communication on Intergroup Cooperation in the Repeated Intergroup Prisoner's Dilemma (IPD) Game

The intergroup prisoner's dilemma (IPD) game was played repeatedly in an attempt to distinguish the dynamic process associated with reciprocation at the intergroup level from that resulting from adaptation at the individual level. Results show that when players were not allowed to communicate with one another, they gradually learned that it does not pay to participate, but when within-group communication was allowed, the overall effect was to increase individual participation. However, this effect varied greatly in later stages of the game. In some cases, intragroup communication eliminated individual participation and rewarded the members of both teams with the mutually cooperative outcome, but in other cases, it intensified the intergroup conflict to its maximal level of full participation. The implications of these findings for conflict resolution are discussed.