Rusbult's Investment Model of Commitment (AQA A-Level Psychology): Revision Notes

Rusbult's Investment Model of Commitment

Overview of the model

Caryl Rusbult developed the investment model to address limitations in social exchange theory by placing commitment at the centre of relationship maintenance. Rather than simply focusing on whether relationships are fair or rewarding, this model suggests there are deeper psychological factors that determine why people stay together.

The model proposes that commitment depends on three key factors working together: satisfaction levels, comparison with alternatives, and investment size. These factors combine to predict how committed someone will be to their relationship, which in turn influences the specific behaviours they use to maintain it.

The three key factors

Satisfaction level

Satisfaction refers to how much partners feel the rewards of their relationship outweigh the costs. This judgement is based on what Rusbult calls the comparison level (CL) - essentially, whether you're getting more from the relationship than you expect based on your past experiences and social norms.

When satisfaction is high, partners feel they receive many rewards (such as support, companionship, and intimacy) whilst experiencing relatively few costs (like conflicts or anxiety). Each partner evaluates satisfaction by comparing what they receive against what they believe they deserve or have experienced before.

Comparison with alternatives

Comparison with alternatives involves partners asking themselves whether their needs might be better met outside their current relationship. This concept, known as CLalt (comparison level for alternatives), includes not just other potential romantic partners, but also the possibility of remaining single.

Partners consider whether alternative relationships would be more rewarding and less costly than their current situation. The more attractive the alternatives appear, the less committed someone is likely to be to their existing relationship.

Investment size

Rusbult recognised that satisfaction and alternatives alone could not fully explain why people stay in relationships. Many satisfying relationships end, and many people remain in unsatisfying ones. This led her to identify investment as the crucial third factor.

Investment encompasses all the resources associated with a relationship that would be lost if it ended. Rusbult distinguished between two types:

Intrinsic investments are resources put directly into the relationship, including tangible elements like money and possessions, as well as intangible resources such as emotional energy and self-disclosure.

Extrinsic investments are resources that did not originally feature in the relationship but have become closely associated with it over time. Examples include possessions purchased together, mutual friendships developed since the relationship began, children, and shared memories.

The greater the investment, the more someone has to lose by ending the relationship, which increases their commitment to maintaining it.

Satisfaction versus commitment

This commitment exists because partners recognise they have made investments they do not want to lose. Consequently, they work harder to maintain and repair their relationship, particularly during difficult periods, because abandoning it would mean losing their investments.

Relationship maintenance mechanisms

Commitment expresses itself through specific everyday behaviours that help maintain relationships. According to the model, committed partners engage in accommodation - putting their partner's interests before their own rather than retaliating when conflicts arise. They also demonstrate willingness to sacrifice for their partner's benefit and show forgiveness when serious problems occur.

Beyond behavioural strategies, committed partners also use cognitive approaches to protect their relationships. They maintain positive illusions about their partner, thinking about them in unrealistically positive ways. They also engage in ridiculing alternatives, viewing other potential partners and relationships more negatively than less committed individuals might.

Evaluation

Supporting research evidence

This cross-cultural and demographic consistency suggests the model identifies universally important features of romantic relationships.

Application to abusive relationships

The investment model provides valuable insight into intimate partner violence (IPV) situations, where it might seem puzzling that victims remain in clearly harmful relationships. The model recognises that satisfaction is not the determining factor in these cases.

Oversimplifies investment

Goodfriend and Agnew (2008) argue that Rusbult's original model presents an overly narrow view of investment. They point out that in early relationship stages, partners have typically made very few concrete investments - they may not even live together yet.

These researchers extended the model by including the investments romantic partners make in their future plans together. Partners become motivated to commit because they want their shared plans for the future to succeed. This criticism suggests the original model fails to capture the full complexity of how investment operates, particularly regarding how future planning influences current commitment levels.

Methodological evaluation

Strengths

Much research supporting the investment model relies on self-report measures such as questionnaires and interviews. Rather than being a limitation, this approach is methodologically appropriate because individual perceptions matter more than objective reality in determining commitment.

What influences your commitment is your belief about your investment size or the attractiveness of your alternatives, regardless of whether these beliefs accurately reflect the situation. Self-report methods effectively capture these subjective perceptions that drive relationship decisions.

Limitations

This methodological limitation challenges the model's validity and reliability, as it may not accurately identify the causal mechanisms underlying relationship maintenance.

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