Social exchange theory is one of the major theoretical perspectives in sociology. It takes its place alongside social systems theory, symbolic interactionism, structural-functionalism, and conflict theory. Three of the major exchange theorists are George C. Homans, Peter Blau, and Richard M. Emerson. This general perspective has roots in a number of disciplines in the social sciences, including the fields of psychology, sociology, anthropology, and microeconomics. Some of the early theoretical influences came from pragmatism, utilitarianism, behaviorism, and functionalism. Other sources of influence include the major works of several social psychologists and cultural anthropologists. From psychology, the work of John Thibaut and Harold Kelley, notably their prize-winning book The Social Psychology of Groups (1959, 1986), is closest to the analysis developed by exchange theorists in sociology, ...