This theory is relevant to many kinds of relationships, with individual differences considered, shown by how profits & losses are personal to each individual relationships. The theory assumes that people monitor costs within the relationship however Argyle argues that we only start to count costs & benefits within the relationship once we become dissatisfied, as costs & profits increase as the relationship progresses. There may be cultural bias, with individualist cultures being encouraged to be self-focused, compared to the collectivist’s who are encouraged to be other’s focused.
Thibaut & Kelley expanded on the Social Exchange Theory, suggesting a comparison of relationship costs & rewards with alternatives. They suggested we compare our current relationships & past relationships in a comparison level & present relationship with others on offer in a comparison level alternative. If the current relationship is less satisfying than either of these there will be dissatisfaction & may lead to breakdown of the relationship.
Simpson found support for this, with people in a relationship giving alternatives a lower rating, which may have been to improve the comparison level of their current relationship. The comparison level has been criticised because it assumes people are selfish & spend time thinking about the costs & rewards of their current relationships. Duck argued people only start to consider alternative relationships when they become dissatisfied with their current relationship. The theory also doesn’t account for those who leave a relationship without an alternative, which the comparison level can’t explain. People stay in abusive relationships despite the costs, which Argyle argued was because they have too much invested – a more likely reason.
The investment model by Rusbult suggests commitment is important in maintenance of relationship & can determine if relationship will breakdown. Commitment demonstrates the level of satisfaction within a relationship, with the model believing that commitment is a reward within the relationship, which is better than the alternatives & substantial investment. However a study found people who had been abused were more committed to the relationship.
The Equity model was suggested by Walster, claiming people expect their relationships to be fair, assuming fairness is more important that profit. People feel satisfied if what they put into a relationship they get out. To make a relationship equitable, both partners must give & receive equally. If a person feels under benefited there is likely to be resentment, but if the person feels over benefited they are likely to feel guilty. This can ultimately lead to a breakdown of the relationship.
De Maris found supporting evidence, he studied US couples & found women’s feelings of inequity are an important predictor of breakdown. A longitudinal study of 200+ couples found that satisfaction ratings were related to equity ratings made a year earlier, which is predicted by the model. The majority of men & women felt that the relationship was equitable, but 65% of women felt they put more into the relationship than they got out. The longitudinal method means that participant variables are consistent, & depicts sequence & continuity of the relationships rather than just a snapshot. However the questions about costs & benefits, from the research, could be influenced by researchers biased, as the study was conducted as an interview & the experimenter could have neglected other possible explanations. Hence the theory may be “artefact of the methodology”.
There is also a question as to whether the Equity theory can explain maintenance of western relationships. It is less effective in collectivist non-western cultures or cultures where freedom to leave the relationship is limited by laws & social norms. The economic theories of relationships are ethnocentric & an etic analysis or attempt to apply them in other cultures would be inappropriate. This suggests that how relationships are maintained is based on the nurture of the individual, with culture being a key factor. Duck argued focusing on narrow aspects of relationships at a particular point in time, rather than a more holistic view research, has misrepresented relationships. It would be better to study relationships as processes rather than states.