Theories of Romantic Relationships and Breakdown

Thibaut and Kelley's social exchange theory (SET) treats a romantic relationship like an economic exchange. Each partner tries to maximise rewards (companionship, sex, emotional support, financial security) and minimise costs (time, effort, stress, missed opportunities). What is left over is the profit:

$\text{profit}=\text{rewards}-\text{costs}$

A relationship is judged worthwhile when it yields a profit, and people are motivated to stay in relationships that are profitable and leave ones that are not. Rewards and costs are subjective: what one person counts as a reward another may count as a cost, and their value changes over time.

Term	Meaning	Everyday examples
Rewards	Things gained from the relationship	Support, sex, company, security
Costs	Things given up or lost	Time, effort, stress, lost alternatives
Profit	Rewards minus costs	The net outcome that drives the choice

Social exchange theory assumes people are fundamentally selfish and hedonistic: we stay when the profit is high and leave when the costs outweigh the rewards.

A profit only means something when it is compared against a standard. SET proposes two reference points a person uses to judge whether a relationship is worth staying in.

The comparison level (CL) is the standard of rewards a person believes they deserve and expect to receive. It is shaped by previous relationships and by social norms (for example, what films, friends and family present as a "normal" relationship). If the profit from the current relationship is above your CL, the relationship seems worthwhile.

The comparison level for alternatives (CLalt) asks a different question: could you do better elsewhere? This weighs the current relationship against realistic alternatives, which include an alternative partner or being single. If an alternative promises a greater profit, the current relationship is at risk.

Judgement	Question it answers	Compared against
CL	Is this relationship good enough for me?	What I expect and deserve
CLalt	Could I do better outside this relationship?	Other partners or being alone

SET also describes four stages a relationship moves through: sampling (exploring rewards and costs, including in other relationships), bargaining (negotiating what each partner gives and receives), commitment (costs and rewards become more predictable) and institutionalisation (norms are firmly established).

A high CLalt does not automatically end a relationship. A committed partner may not even notice attractive alternatives, which is a gap SET struggles to explain.

Walster et al.'s equity theory was developed to fix a weakness in SET. It argues that partners are not simply chasing the biggest profit; they want to feel the relationship is fair. Equity means each partner's ratio of inputs to outputs is roughly equal, not that both partners put in or take out the same amount.

Crucially, inequity in either direction causes dissatisfaction:

• The under-benefitting partner feels anger, hostility and resentment.
• The over-benefitting partner feels guilt, discomfort and shame.

Situation	Ratio of inputs to outputs	Typical feeling
Equity	Roughly equal for both partners	Satisfaction
Under-benefit	You put in more than you get back	Anger, resentment
Over-benefit	You get back more than you put in	Guilt, discomfort

When a relationship feels inequitable, partners are motivated to restore equity. They may do this in reality (renegotiating who does what) or cognitively (revising their perception of inputs and outputs so the relationship feels fair again). The greater the perceived inequity, the greater the effort to restore it, or the more likely the relationship is to break down.

Equity theory extends social exchange theory: profit still matters, but a fair distribution of that profit matters more than its raw size.

Rusbult's investment model explains why people stay in relationships, including ones that make them unhappy. Commitment, she argued, is the key factor, and it depends on three things.

• Satisfaction — the extent to which partners feel rewards exceed costs relative to their comparison level (essentially SET's profit judgement).
• Comparison with alternatives — whether needs could be better met outside the relationship (CLalt).
• Investment size — the resources already put into the relationship that would be lost if it ended.

Rusbult distinguished two kinds of investment:

Investment type	What it is	Examples
Intrinsic	Resources put directly into the relationship	Effort, time, self-disclosure, emotion
Extrinsic	Resources that become linked to it	Shared possessions, children, friends, a home

The central insight is that satisfaction alone does not predict whether people stay. A dissatisfied partner with few alternatives and heavy investment can still be highly committed, which is why the model can explain why some people remain in unsatisfying or even abusive relationships. Committed partners also work to maintain the relationship through accommodation (managing conflict positively), willingness to sacrifice and forgiveness.

The distinctive contribution of the investment model over SET and equity theory is investment. Satisfaction and alternatives explain attraction; investment explains persistence.

Duck's phase model describes how a relationship falls apart as a sequence of four phases. Each phase begins only once a threshold (a point of realisation) is crossed, so the model is about the process of breaking up, not a single event.

In the intra-psychic phase one partner privately broods on their dissatisfaction and the partner's faults, saying nothing. In the dyadic phase they confront the partner and discuss the problems, which may either resolve or deepen the conflict. In the social phase the breakup is made public: friends and family take sides, offer support and can push the couple apart or try to patch things up. In the grave-dressing phase the relationship is finalised and each partner constructs a favourable personal story about it ("I was a good partner; it just wasn't right"), protecting their reputation for future relationships. Rollie and Duck later added a fifth resurrection phase, in which ex-partners apply what they have learned to future relationships.

(Extra context — Rollie and Duck's fifth "resurrection" phase is a later revision. AQA's specification names the original four phases, so learn intra-psychic, dyadic, social and grave-dressing as the core model.)

A strong answer weighs these theories against evidence and against each other.

Social exchange theory — concepts are hard to define and measure. What counts as a reward or a cost is subjective and varies between people, making the theory difficult to test scientifically. SET may also not apply to all relationships: Clark and Mills distinguished exchange relationships (where partners do keep track of rewards and costs, such as between colleagues) from communal relationships (romantic couples, where partners give without keeping score). This suggests SET describes some relationships better than the intimate ones it is meant to explain.

Equity theory — supporting evidence but individual and cultural differences. Utne et al. surveyed married couples and found that those who saw their relationship as equitable were more satisfied than under- or over-benefitting partners, supporting the theory. However, Huseman et al. argued equity does not matter equally to everyone: some people are benevolents (happy to give more) and some are entitleds (happy to take more). Equity may also matter less in collectivist cultures, so the theory risks being culturally biased.

Rusbult's model — strong, cross-cultural research support. Le and Agnew's meta-analysis of 52 studies (around 11,000 participants) found that satisfaction, quality of alternatives and investment size all reliably predicted commitment across cultures and both genders. The model also has real-world value in explaining why people remain in abusive relationships, where investment and lack of alternatives sustain commitment despite low satisfaction.

Duck's model — practical value but limited generalisability. Because the model identifies distinct phases, it suggests where to intervene (for example, encouraging positive reframing in the intra-psychic phase), giving it real-world application. However, the research is based largely on individualist-culture, heterosexual relationships and may not generalise; it can also oversimplify breakdown by presenting it as a fixed forward sequence when real breakups often skip phases or move back and forth.

1. Confusing comparison level with comparison level for alternatives

CL is what you expect and feel you deserve from a relationship; CLalt is whether another option (a different partner or being single) would give you more. Mixing them up loses easy marks. CL is an internal standard; CLalt is a comparison with the outside world.

2. Treating social exchange and equity theory as the same thing

They are not identical. SET is about maximising profit; equity theory adds fairness, arguing that an equal ratio of inputs to outputs matters more than the raw size of the profit. Remember that over-benefitting also causes dissatisfaction under equity theory, which SET cannot explain.

3. Forgetting that investment is what makes Rusbult's model distinctive

Satisfaction and comparison with alternatives already appear in earlier theories. If you describe the investment model without emphasising investment size and commitment, you have not shown what is unique about it, and you lose the point that commitment (not satisfaction) explains why people stay.

4. Muddling the order of Duck's phases

The sequence is intra-psychic → dyadic → social → grave-dressing. A common slip is placing the social phase before the dyadic phase. Remember the logic: you brood privately first, then confront your partner, then go public, then rewrite the story.

5. Describing theories without evaluating them

Higher-mark essay questions are dominated by AO3. Naming Utne, Le and Agnew, or Clark and Mills, and using them to build a developed point, earns far more than another paragraph simply restating what each theory claims.