1. the tendency to assume that one’s personal qualities and characteristics, including attitudes and values, are common in the general social group or culture.

2. in mob and crowd settings, the tendency for individuals to assume that atypical, unusual behaviors are allowable because many others in the situation are performing such actions (“everybody’s doing it”). See collective behavior; social contagion; emergent-norm theory.

3. in self-help and psychotherapy groups, a curative factor fostered by members’ recognition that their problems and difficulties are not unique to them but instead are experienced by many of the group members. See also therapeutic factors.