Law of Effect

The law of effect is a principle associated with learning and behavior. It states that behaviors leading to satisfying outcomes are more likely to be repeated than those with unwanted consequences.

Since psychology emerged as a discipline, psychologists have been interested in the factors that are important in behavior change and control. One of the first principles associated with learning and behavior is the law of effect, which states that behaviors with satisfying consequences are likely to be repeated, whereas those with undesired outcomes are less likely to recur.

American psychologist Edward Lee Thorndike (1874–1949), developed this principle and contributed significantly to the field of operant conditioning. In operant conditioning, rewards or positive reinforcers are used to strengthen desired behavior (e.g., providing food to a hungry pigeon after it has pecked at a key). Negative reinforcers are unpleasant stimuli that are removed when the desired response has been obtained (e.g., a loud horn that sounds until a dog sits when instructed).


Negative reinforcement—
Used in operant conditioning, an unpleasant consequence that is removed when a desired response has been obtained (e.g., a loud horn that sounds until a dog sits when instructed).
Positive reinforcement—
Used in operant conditioning, a reward that is used to strengthen a desired behavior (e.g., providing a hugto a child who acted in a polite manner).
Operant conditioning—
The process of associating a behavior with a consequence, which may be positive or negative.

Initially, Thorndike drew parallels between positive outcomes, termed reinforcements by the behaviorists, and negative outcomes, 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 the law of effect and the law of exercise could account for all behavior. As such, psychologists had no need to refer to abstract thought in defining the way that behavior is learned. According to Thorndike's view, everything is associated with the effects of reward and punishment.

See also Conditioning ; Skinner, B. F.



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B. F. Skinner Foundation, 18 Brattle St., Ste. 451, Cambridge, MA, 02138, (617) 661-9209, info@bfskinner. org, .