Group-Induced Extremization: Review of Evidence and a Minority-Change Explanation

A review of evidence from a number of experiments suggests that as a result of discussion the average of the group members' positions (attitudes, judgments) becomes more extreme. These shifts seem to occur primarily when group members' initial positions are distributed across the two sides of the scale in such a way as to create a majority-minority constellation. Accordingly, it is proposed that underlying the extremity-shifts reported in the literature is the movement of a minority toward the majority's side. That such minority-change is nor the only source of extremization is suggested by one study finding that group discussion enhances the extremity of individual positions. An analysis of the special distribution of positions existing on the items selected in that experiment permits the following conclusion. Discussion-induced extremization is (also) caused by the impact of arguments in the discussion favoring the side which most or all members preferred to begin with. Other explanations cannot be discarded at the present time. At the least they point to important aspects of small-group functioning which it would seem fruitful to investigate.