Majority Influence Process in Group Judgment: Test of the Social Judgment Scheme Model in a Group Polarization Context

The purpose of this study is to test Davis’s (1996) Social Judgment Scheme (SJS) model, which was proposed as a predictive model of group decision making with continuous alternatives. The SJS model assumes that individual group members’ influence on the group decision exponentially declines with the distance from other members’ judgments (i.e. majority influence process). Fifty-five 3-person groups engaged in eight group polarization tasks. First, the model fits of the SJS model and the Averaging model were compared in terms of the predictive accuracy. Results indicted that the SJS model yielded accurate predictions more often than the Averaging model. Second, a different analytical approach confirmed the model’s corollary—the skewness of individual judgments distribution was negatively correlated with the direction of group polarization. These findings support the model’s assumption of majority influence process in continuous alternatives tasks.