Edited by Van Lange, Kruglanski, and HigginsAuthor Note: With the exception of the section on origins of the theory, this chapter was prepared following the death of the first author, Caryl Rusbult, our mentor and dear friend.
AbstractThe investment model of commitment processes is rooted in interdependence theory and emerged from the broader scientific zeitgeist of the 1960s and 1970s that sought to understand seemingly irrational persistence in social behavior. The investment model was developed originally to move social psychology beyond focusing only on positive affect in predicting persistence in a close interpersonal relationship. As originally tested, the investment model holds that commitment to a target is influenced by three independent factors: satisfaction level, quality of alternatives, and investment size. Commitment, in turn, is posited to mediate the effects of these three bases of dependence on behavior, including persistence. Commitment is presumed to bring about persistence by influencing a host of relationship maintenance phenomena. The investment model has proven to be remarkably generalizable across a range of commitment targets, including commitment toward both interpersonal (e.g., abusive relationships, friendships) and non-interpersonal (e.g., job, sports participation, support for public policies) targets.Empirical support for the investment model is presented as well as a review of recent applications of the model and a proposed extension of it.3