Accuracy and bias in adolescents' perceptions of friends' substance use.

This study tested competing hypotheses related to the false consensus effect and pluralistic ignorance by examining the accuracy and bias of adolescents' perceptions of peer substance use and the effects of their own substance use, gender, and age on perceptions of peer behavior. Two samples (ns = 163 and 2,194) that collected data on peer nominations, perceptions of peer substance use, and self-reports of substance use were used in analyses. Results from both samples provided evidence supporting the false consensus effect, that is, adolescents' reports of their friends' substance use were biased in the direction of their own use. Users and nonusers did not differ in accuracy of perceptions; however, across all substances and samples, they differed significantly in bias. Substance users displayed nearly perfect liberal bias, assuming their friends also used substances. Nonusers displayed an opposite, conservative bias, assuming their friends did not use substances. Gender and age differences in bias also were observed, with older adolescents and girls having more liberal biases than younger adolescents and boys. Results suggest the importance of differentiating the effects of actual and perceived peer substance use.