Social exchange theory is a sociological and psychological theory that studies the social behavior in the interaction of two parties that implement a cost-benefit analysis to determine risks and benefits. The theory also involves economic relationships—the cost-benefit analysis occurs when each party has goods that the other parties value. Social exchange theory suggests that these calculations occur in romantic relationships, friendships, professional relationships, and ephemeral relationships as simple as exchanging words with a customer at the cash register. Social exchange theory says that if the costs of the relationship are higher than the rewards, such as if a lot of effort or money were put into a relationship and not reciprocated, then the relationship may be terminated or abandoned. The most comprehensive social exchange theories are those of the American social psychologists John W. Thibaut (1917–1986) and Harold H. Kelley (1921–2003), the American sociologists George C. Homans (1910–1989), Peter M. Blau (1918–2002), Richard Marc Emerson (d. 1982), and Claude Lévi-Strauss (1908–2009). Homans defined social exchange as the exchange of activity, tangible or intangible, and more or less rewarding or costing between at least two persons. After Homans founded the theory, other theorists continued to write about it, particularly Peter M. Blau and Richard M. Emerson, who in addition to Homans are generally thought of as the major developers of the exchange perspective within sociology. Homans' work emphasized the individual behavior of actors in interaction with one another. Although there are various modes of exchange, Homans centered his studies on dyadic exchange. John Thibaut and Harold Kelley are recognized for focusing their studies within the theory on the psychological concepts, the dyad and small group. Lévi-Strauss is recognized for contributing to the emergence of this theoretical perspective from his work on anthropology focused on systems of generalized exchange, such as kinship systems and gift exchange. Thibaut and Kelley Thibaut and Kelley based their theory on small groups related with dyadic relationships. They used the reward-cost matrices from Game Theory and discovered some clues of individuals’ interdependence such as the power of a party over each other, also known as the “correspondence” versus “noncorrespondence” of outcomes. Additionally, they suggest that an individual can unilaterally affect her or his own outcomes in a relationship through chosen behaviors. They could predict the possible course of a social interaction through the analysis of aspects of power in an encounter. They also experimented on how the