Social Corroboration and Opinion Extremity.

Four studies found that social corroboration of one's (pro/con) attitudinal position leads to increases in attitude extremity. Study 1 focused on attraction ratings made by college women. This study demonstrated both increases in opinion extremity following corroboration and decreases in opinion extremity following contradiction. Study 2 focused on dental chair comfort ratings made by dental patients and found greater opinion extremity following corroboration from either fellow patients or the dentist. Study 3 reported greater charity donation amounts as well as heightened opinion confidence following corroboration. Study 4 replicated Study 1 varying duration of stimulus exposure and found that, as predicted, confidence scores were affected more by the corroboration/contradiction manipulation when initial exposures were brief. Unexpectedly, however, the affect of corroboration on attraction ratings, was not moderated by initial exposure time. Rather, across both long and short exposure times, attraction scores were most extreme following corroboration and least extreme following contradiction. Path analyses in Study 4 supported the view that this association between corroboration and extremity was mediated by confidence. This research indicates that the relationship between corroboration and opinion extremity appears to be respectably robust across populations and target variables, and is not specific to sensitive within subject designs. Moreover, Study 3 indicates that social corroboration is capable of increasing the extremity of behavior having real consequences for participants. The data are discussed in terms of possible moderator variables, as well as theories of group polarization and opinion extremity.