Skinner, Burrhus Frederic (1904–1990), American psychologist. Skinner made a major contribution to 20th-century psychology. He is famous as a major proponent of behaviorism, a philosophy that studies human behavior in terms of physiological responses to the environment and believes that human nature can be revealed through the controlled scientific study of these responses. Skinner conducted innovative experiments in animal learning, training laboratory animals to perform a number of complex actions. To carry out some of his experiments he designed the Skinner box, an apparatus later adopted by pharmaceutical research for observing the effects of drugs on animal behavior. His work with research animals led to his development of the principles of programmed learning. His revolutionary innovations in educational method included the invention of teaching machines. Central to his methods was the concept of reinforcement, or reward.