A behavior is followed by a consequence that reduces its future probability. Punishment is that process. It can involve the presentation of an aversive event or the removal of a positive one.

Punishment can suppress behavior quickly, yet it has well-documented side effects: escape and avoidance, emotional reactions, aggression, and failure to teach desired alternatives. Its effects are often context-specific and temporary once the punishing agent is absent. For these reasons, behavior analysts generally prefer reinforcement of alternative behaviors over punishment.

In everyday life, punishment ranges from social disapproval to formal legal sanctions. Its effectiveness depends on immediacy, consistency, and the availability of other ways to obtain reinforcement. Ethical considerations limit the use of aversive procedures, especially with vulnerable populations. Understanding punishment clarifies both its power and its limitations as a behavior-change tool.

• Consequence that decreases behavior probability
• Can be positive or negative in technical sense
• Often produces unwanted side effects
• Less preferred than reinforcement of alternatives