APA Dictionary of Psychology

an approach to psychology in which behavior is conceptualized in terms of stimulus and response. The fundamental goal of adherents is therefore describing functional relationships between stimulus and response—that is, manipulating a stimulus and observing the response. S–R psychology developed from Edward L. Thorndike’s connectionism and John B. Watson’s behaviorism, and S–R theories thus tend to be behavioral rather than cognitive. Examples include Clark L. Hull’s reinforcement theory (see Hull’s mathematico-deductive theory of learning) and Edwin R. Guthrie’s contiguity learning theory. S–R theories are sometimes contrasted with cognitive theories of learning (see S–S learning model), such as purposive behaviorism or Gestalt psychology. See also S–O–R psychology.