Social Norm
An informal rule of behavior shared by a group, sustained by mutual expectation and social sanction.
Also known as: Social norms, Norm, Norms
Category: Psychology & Mental Models
Tags: psychology, communications, coordination, cooperation, social-norms
Explanation
Social norms are unwritten rules that guide what people do, what they expect of others, and what they sanction when violated. Unlike laws, norms are enforced informally through approval, disapproval, gossip, status, shame, and exclusion. They cover everything from greeting rituals and tipping practices to honesty in trade, queuing, dress codes, and online etiquette. Cristina Bicchieri distinguishes social norms from descriptive norms (what people do) and from personal moral rules: a social norm exists when people conform conditional on believing that others both follow and expect them to follow it. This dual expectation - empirical (others do X) and normative (others think I should do X) - is what differentiates norms from mere conventions or habits. Norms emerge from coordination problems, evolutionary advantage of cooperative behavior, deliberate cultivation, or precedent that gets reinforced. They are often Pareto-improving when they coordinate behavior on cooperative outcomes, but they can also be harmful (foot-binding, blood feuds) and persist long after their original rationale fades. Understanding norms matters for designing institutions, changing entrenched behavior, and analyzing why exhortation and incentives often fail when expectation structures stay intact. Norm change typically requires shifting common knowledge about what others do and expect, not just persuading individuals.
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