law of effect
A proposition formulated by the US psychologist Edward Lee Thorndike (1874–1949) in his book Animal Intelligence: Experimental Studies (1911) as follows: ‘Of several responses made to the same situation, those which are accompanied or closely followed by satisfaction [are] more firmly connected with the situation … ; those which are accompanied or closely followed by discomfort … have their connections with the situation weakened’ (p. 244). According to this law, responses that lead to reward tend to increase in strength, whereas those that lead to punishment tend to decrease in strength. The first part of the law has been amply corroborated by empirical studies and is one of the foundation stones of modern behaviourism. See also associationism, connectionism (2), reinforcement (1). Compare law of exercise.