Social Exchange Theory posits that relationship satisfaction depends on the balance of rewards (benefits, support) and costs (effort, sacrifice), compared against one's comparison level (expectations) and alternative relationships. Over time, couples in satisfying relationships develop interdependence characterized by mutual commitment and investment.
Have couples report their perceived rewards, costs, and comparison levels longitudinally to predict who remains together; discuss why economic models sometimes fail to capture relationship commitment (e.g., love, moral obligation).
Social Exchange Theory applies an economic logic to something that feels deeply personal: intimate relationships. The core claim is that people implicitly weigh the rewards they receive from a relationship — affection, support, companionship, shared resources — against the costs they incur — effort, sacrifice, conflict, missed alternatives. This is not cynicism; it is a description of a mental accounting that happens largely below conscious awareness. From your social psychology overview, you already know that social behavior is shaped by incentive structures even when people don't frame it that way.
The key insight that makes this more than simple arithmetic is the concept of the comparison level (CL) — your expectation of how much reward you deserve based on past experience, cultural norms, and what you observe in others' relationships. Someone raised in a high-conflict household may have a low CL and find an average relationship very satisfying; someone whose previous partner was exceptionally attentive may have a high CL and find the same relationship disappointing. Two people in objectively identical relationships can report very different satisfaction levels because their comparison levels differ.
Even more powerful is the comparison level for alternatives (CLalt) — not what you expect from relationships in general, but specifically what you think you could get if you left this relationship. CLalt determines whether someone *stays* in a relationship, even when they're dissatisfied. A person may be unhappy (rewards < CL) but remain in a relationship because their alternatives look even worse (rewards > CLalt). This explains a common pattern: why do people stay in relationships they openly describe as unsatisfying? Their CLalt is low — few social connections, economic dependence, geographic constraints.
Scholars like Caryl Rusbult built on this foundation with the investment model, which adds a third element: how much someone has put into the relationship that they would lose by leaving — shared history, mutual friends, financial entanglement, children. High investment raises the psychological cost of exit even when rewards drop. This captures what pure exchange logic misses: commitment is not just about whether you're getting a good deal now, but about how much you have at stake. Relationships that appear economically irrational — someone staying despite few rewards and many costs — often make sense once investment is factored in.
The limits of the model are also worth naming. Love, moral obligation, and attachment (your soft prerequisite) introduce forces that are hard to reduce to cost-benefit calculations. Attachment security shapes how people interpret costs — an anxiously attached person experiences the same mild conflict as a much larger cost than a securely attached person would. The model is most predictive in early and middle-stage relationships; deeply committed relationships develop norms of fairness and communal orientation that make explicit exchange accounting feel inappropriate to the partners themselves. Social Exchange Theory is therefore best understood as a starting model — accurate enough to generate testable predictions, but requiring extensions when emotion, identity, and long-term commitment are in play.
No topics depend on this one yet.