a generic name for theories of learning which stress observable behavioural responses and do not deal with 'unobservables' such as mental states or motivation. Key theorists were John B. Watson (1878-1958), E. L.Thorndike (1874-1949), and B.F.Skinner (1904-1990) who practised in the early to middle years of the 20th century. Learning is understood as being a response to a stimulus which engenders that response. It was heavily influenced by experimentation with animals such as dogs, rats, and pigeons (see conditioning, stimulus-response).