the branch of psychology that explores the operation of mental processes related to perceiving, attending, thinking, language, and memory, mainly through inferences from behavior. The cognitive approach, which developed in the 1940s and 1950s, diverged sharply from contemporary behaviorism in (a) emphasizing unseen knowledge processes instead of directly observable behaviors and (b) arguing that the relationship between stimulus and response was complex and mediated rather than simple and direct. Its concentration on the higher mental processes also contrasted with the focus on instincts and other unconscious forces typical of psychoanalysis. More recently, cognitive psychology has been influenced by approaches to information processing and information theory developed in computer science and artificial intelligence. See also cognitive science.