Social Exchange Theory

A-Level only — this content is not assessed at AS-Level.

Social Exchange Theory

Social exchange theory (SET) applies an economic model to human relationships: people are rational actors who seek to maximise the rewards they receive from a relationship whilst minimising the costs. Proposed by Thibaut and Kelley (1959), SET argues that the decision to enter, maintain, or leave a relationship is governed by the calculation of whether the relationship is 'profitable' — whether rewards sufficiently exceed costs. This framework treats relationships as exchanges of valued resources, structurally analogous to economic transactions.

Rewards, Costs, and Profit

Rewards are anything the relationship provides that meets a person's needs or produces positive affect: companionship, love, emotional support, sexual satisfaction, social status, practical assistance, shared experiences, and financial security. Costs are anything that is effortful, unpleasant, or involves sacrifice: time, emotional energy, conflict, compromising personal goals, and opportunity costs (other relationships foregone). Profit = Rewards − Costs. The higher the profit, the more the relationship is valued — but profit is not the only determinant of relationship satisfaction or stability.

The Comparison Level (CL)

Thibaut and Kelley proposed that people evaluate relationship profit against a standard — the comparison level (CL). The CL is a subjective threshold — the level of profit the person believes they deserve, based on past relationship experience, social norms, and cultural expectations. If a relationship's profit exceeds the CL, the person is satisfied with the relationship. If profit falls below the CL, they are dissatisfied — even if the relationship is objectively rewarding by an external standard.

The CL is both personal and dynamic. A person who has experienced highly rewarding previous relationships develops a high CL — they require substantial profit to feel satisfied. A person with a history of unrewarding relationships develops a low CL — they may feel satisfied with a relationship that others would consider poor. Cultural norms also shape CL: societies with strong norms of romantic love and individual fulfilment set high CL benchmarks; others emphasise duty and stability, setting different standards.

The Comparison Level for Alternatives (CLalt)

A second standard — the comparison level for alternatives (CL_alt) — determines not satisfaction but stability. The CL_alt is the profit available in the best realistic alternative situation — which may be another relationship, or no relationship at all (independence). If the current relationship's profit exceeds the CL_alt, the person will remain in the relationship — even if dissatisfied. If the CL_alt exceeds the current relationship's profit, the person is likely to leave.

This generates a crucial distinction:

A relationship can be satisfying but unstable: profit exceeds CL (satisfied) but a highly attractive alternative (high CL_alt) tempts departure.
A relationship can be unsatisfying but stable: profit falls below CL (dissatisfied) but no better alternative exists (low CL_alt) — the person stays because they perceive nothing better available.

The unsatisfying-but-stable pattern explains why people remain in poor-quality relationships: when CL_alt is very low — because the person believes they have no better options, lacks social support, or faces practical barriers to leaving — they will stay despite chronic dissatisfaction. This has significant implications for understanding domestic abuse, where abusers systematically lower victims' perceived CL_alt by isolating them, undermining their self-esteem, and creating financial dependence.

Stages of Relationship Development

Thibaut and Kelley proposed four stages of relationship development, each characterised by changing exchange dynamics. In the sampling stage, people try out relationships and compare the rewards and costs of different partners. In the bargaining stage, partners negotiate the terms of the exchange — testing what each can offer and what they require. In the commitment stage, partners settle into stable exchange routines as mutual profit is established. In the institutionalisation stage, exchange norms are taken for granted — the relationship becomes embedded in shared routines and mutual expectations.

Key Takeaways

SET (Thibaut and Kelley, 1959): relationships are exchanges — people seek to maximise profit (rewards − costs). Rewards: companionship, support, status. Costs: time, effort, conflict.
Comparison level (CL): subjective standard of deserved profit — based on past experience and social norms. Profit > CL → satisfied; profit < CL → dissatisfied.
Comparison level for alternatives (CL_alt): profit in the best available alternative. Current profit > CL_alt → stay; CL_alt > current profit → likely to leave.
Crucial distinction: satisfied but unstable (high CL_alt tempts departure); unsatisfying but stable (low CL_alt — no better options perceived).
The unsatisfying-but-stable pattern explains why people remain in poor-quality relationships — abusers exploit this by lowering victims' perceived CL_alt.
Four developmental stages: sampling → bargaining → commitment → institutionalisation.