Law of Effect

A principle associated with learning and behavior which states that behaviors that lead to satisfying outcomes are more likely to be repeated than behaviors that lead to unwanted outcomes.

Psychologists have been interested in the factors that are important in behavior change and control since psychology emerged as a discipline. One of the first principles associated with learning and behavior was the Law of Effect, which states that behaviors that lead to satisfying outcomes are likely to be repeated, whereas behaviors that lead to undesired outcomes are less likely to recur.

This principle, which most learning theorists accept as valid, was developed by Edward Lee Thorndike, who provided the basis for the field of operant conditioning. Prior to Thorndike, many psychologists interested in animal behavior attributed learning to reasoning on the animal's part. Thorndike instead theorized that animals learn by trial and error. When something works to the animal's satisfaction, the animal draws a connection or association between the behavior and positive outcome. This association forms the basis for later behavior. When the animal makes an error, on the other hand, no association is formed between the behavior that led to the error and a positive outcome, so the ineffective behavior is less likely to recur.

Initially, Thorndike drew parallels between positive outcomes, which would be termed reinforcement s by the behaviorists, and negative outcomes, which would be referred to as punishments. Later, however, he asserted that punishment was ineffective in removing the connection between the behavior and the result. Instead, he suggested that, following a punishment, behavior was likely to be less predictable.

Thorndike also developed his Law of Exercise, which states that responses that occur in a given situation become more strongly associated with that situation. He suggested that these two laws could account for all behavior. As such, psychologists had no need to refer to abstract thought in defining the way that behavior is learned. Everything is associated with the effects of reward and punishment, according to Thorndike.