Social norms theory provides a model for understanding human behavior that has important implications for health promotion and prevention. It states that our behavior is influenced by incorrect perceptions of how other members of our social groups think and act. For example, an individual may overestimate the permissiveness of peer attitudes or behavior with respect to alcohol or underestimate the extent to which peers engage in healthy behavior. The theory predicts that overestimations of problem behavior will increase these problem behaviors while underestimations of healthy behaviors discourage individuals from engaging in them. Thus, correcting these misperceptions is likely to result in decreased drinking or increased prevalence of healthy, protective behaviors. These assumptions have been validated by extensive research on student drinking and by interventions to promote safe drinking and abstinence on college campuses. Other social norms interventions have been developed to reduce cigarette smoking, prevent sexual assault, improve academic climate, and reduce prejudicial behavior.

Social norms interventions focus on peer influences, which have been found to be more influential in shaping individual behavior than biological, personality, familial, religious, cultural and other influences (Berkowitz & Perkins, 1986a; Perkins, in-press). These peer influences are based more on what we think our peers believe or do (the "perceived norm") than on their real beliefs or actions (the "actual norm"). This misperception and the effect it has on individuals provides the basis for the social norms approach to prevention. By presenting correct information about peer group norms, perceived peer pressure is reduced and individuals are more likely to express pre-existing attitudes and beliefs that are health-promoting.