Us without them: evidence for an intragroup origin of positive in-group regard.

Four experiments examined whether group formation and positive in-group regard require interaggregate comparison as the in-group-requires-an-out-group assumption of the metacontrast principle implies. The authors fostered novel social aggregates with or without a contrasting aggregate with which members could compare and varied intra-aggregate factors (interaction or interdependence). Regardless of whether interaggregate comparison was feasible, the intra-aggregate factors increased the perceived entitativity of the aggregate and positive regard toward the aggregate (i.e., social attraction and cooperation among members). Mediation analyses were consistent with the possibility that the intra-aggregate factors promoted entitativity, which in turn promoted in-group regard. These data suggest that group formation and in-group regard have intragroup origins and do not require comparison with a contrasting social aggregate.