Patterns and importance of self-other differences in college drinking norms.

College students overestimate other students' drinking behavior (descriptive norms) and attitudes (injunctive norms). This study explored the effects of demographics, norm type, and reference group on the magnitude of self- other differences (SODs). Participants (N = 1,611; 64% women) completed surveys assessing demographics, drinking patterns, and perceived norms. A subset of 122 students provided consumption data 1 month later to test predictors of changes in drinking. Overall, women and non-Greeks (Greek = member of fraternity or sorority) reported larger SODs for both norm types compared with men and Greeks. Heavier drinkers reported smaller SODs. Gender x Reference Group interactions revealed that women had larger SODs for reference groups increasingly distal to them; for men, the largest SODs occur for close friends versus more distal groups. Larger SODs for descriptive norms predicted increases in drinking, consistent with social norms theory.