A sanction is a reward or punishment that enforces social norms. It can be positive or negative, formal or informal. A smile is a positive informal sanction. A prison sentence is a negative formal sanction. Sanctions are how societies encourage conformity and discourage deviance.

Formal sanctions are imposed by official institutions: courts, schools, workplaces. They are written down and applied consistently. Informal sanctions are imposed by everyday people: friends, family, strangers. They are not written down but are often more powerful. A look of disgust can hurt more than a fine.

Types of sanctions

• Positive formal: awards, promotions, medals
• Positive informal: compliments, smiles, approval
• Negative formal: fines, imprisonment, expulsion
• Negative informal: gossip, ridicule, ostracism

Sanctions work best when they are consistent and widely accepted. When norms are contested, sanctions can backfire. Punishing a peaceful protester can increase sympathy for the cause. The effectiveness of a sanction depends on the context and the community's values.