This project develops and tests a theory of relational cohesion that indicates how and when power in negotiations affects the development of commitment among parties to an exchange. It does so through three laboratory experiments, one on each of three commitment behaviors: (1) staying in the relationship even if better ones become available; (2) giving each other gifts that do not require immediate reciprocity; (3) contributing to a joint fund with the other. Each experiment will assign 80 same-sex dyads to one of four experimental conditions in a standard two-party explicit bargaining setting. The theory and experimental test will suggest how an exchange relationship having an instrumental foundation becomes more expressive if exchanges are successfully negotiated over time. This project will contribute to our understanding of the emergence of commitment in human interactions, illuminating how people come to have positive emotions toward each other quite beyond the satisfaction of self-interested needs. It provides an important link between laboratory social psychology studies of exchange and the sociology of emotions, a field that has grown substantially in very recent years.