Social exchange theory is a social psychological an sociological perspective that explains social change and stability as a process of negotiated exchanges between parties. Social exchange theory posits that all human relationships are formed by the use of a subjective cost-benefit analysis and the comparison of alternatives. For example, when a person perceives the costs of a relationship as outweighing the perceived benefits, then the theory predicts that the person will choose to leave the relationship. The theory has roots in economics, psychology and sociology.