law of effect

The view formulated by the psychologist E. L. Thorndike (1874–1949) that actions that lead immediately to pleasure are remembered and repeated, eventually fossilizing into habits, whereas actions leading to pain are suppressed or avoided. It is notable that the law explains actions in terms of the past, not in terms of expected pleasure or pain. Although it formed a major tenet of the theory that learning is essentially a matter of conditioning, and hence suffered with the eclipse of behaviourism, the law is commonly held to encapsulate something essential to the nature of pain and pleasure, which is their function in controlling learning. A version of the law of effect governs neural networks, or artificial parallel distributed processing systems, which are trained by the ‘back propagation of error’; see connectionism.