Social norms

What it means

Social norms are shared standards that guide behavior, and the influential distinction is between descriptive norms — what people in fact do — and injunctive norms — what people approve or disapprove of. The two operate through different psychological routes: descriptive norms tell us what is likely effective or normal in a setting, while injunctive norms invoke the threat of social sanction and the desire for approval. Norm-based interventions are most powerful when the two align, but a descriptive norm used alone can backfire when it inadvertently advertises that an undesirable behavior is common, pulling people toward it (a boomerang effect). The strength of a norm also depends on whether it is made salient at the moment of action and on whether the reference group is one the person identifies with. Pairing a descriptive norm with an injunctive cue of approval — the classic example being an 'efficient' rating for low energy users — prevents the backfire. It matters because correctly engineered norm messages are a staple of public-health, sustainability, and tax-compliance campaigns.