Intragroup social influence and intergroup competition

Three experiments examined the role of intragroup social influence in intergroup competition. In the context of a mutual fate control situation, participants in Experiment 1 demonstrated more intergroup competition in the presence than in the absence of social support for shared self-interest. Experiment 2 revealed that, in the context of a Prisoner’s Dilemma Game, this social support effect was stronger when noncorrespondence of outcomes between the interacting groups was low than when it was high. Results from Experiment 3 were consistent with the possibility that the effect of social support is attenuated when noncorrespondence of outcomes is high because under these circumstances intergroup competition is prescribed by a norm of group interest. The implications of these findings for understanding the antecedents of interindividual–intergroup discontinuity are discussed. The 20th century, perhaps more so than any other, will be remembered for the atrocious armed conflicts that have marked its course. It is estimated that, just in its final decade, armed conflicts have claimed the lives of 30 million people and moved 45 million people from their homes (McGuire, 1998). Research on interindividual–intergroup discontinuity (e.g., Insko et al., 1987