Abstract
This study examines the underestimation of social influence that occurs when an entering-group joins a pre-existing group and also analyzes the determinants (In-Group-Identity: InG-Id & Common-In-Group-Identity: CoInG-Id) of this phenomenon. In Exp 1, 36 participants were assigned to 12 groups; half the groups were then classified as pre-existing groups and the remaining, as entering-groups. Participants made group-decisions within their respective groups. Entering-groups then joined the pre-existing groups and the task was repeated in the resulting 6-member groups. Exp 1 revealed that existing-groups estimated their impact on decision-making to be less than that of the entering-groups in the 6-member phase. In Exp 2, 49 participants were allocated to pre-existing groups and confederates served as the entering-group. These participants were distributed according to an InG-Id × CoInG-Id ANOVA design. Underestimation was observed in the high-InG-Id condition. High-CoInG-Id had no effect on the underestimation. High-CoInG-Id decreased the cognized conflict level towards the out-group. These results suggest that there exists a relationship among the underestimation, cognition of conflict level, and group-identity in the existing-group.
