These concepts were investigated by May and Hamilton, who presented female participants with photographs of men of whom they had to rate. The independent variable in this study was the music that was played whilst rating was taking place. The music was either pleasant or unpleasant; there was also a control condition. They found when females were listening to pleasant music rating were significantly higher than when in an unpleasant condition. This suggests that mood can be associated with people which can either enhance of hinder attraction.
Though this was a lab experiment, from which causal relationships can be established as confiding variables are controlled, there are still several shortcomings of this design. Firstly the sample was all female, due to this gender bias we can not generalise the findings to a male population, as a result the findings lack population validity. Secondly lab experiments tend to be artificial and too controlled as a result the study lacks mundane realism. In real life we do not judge people based on the photos, instead other factors such as height, build, ability to communicate and converse all effect our decision. Due to this the findings may not be applicable to real life so they lack ecological validity.
Overall the reinforcement affect model provides an adequate account for the formation and maintenance of relationships. However the theory is lacking in some regards is it is reductionist. It takes the complex nature of relationships and boils it down to the simple stimulus and response link. As a result the theory is oversimplified as it ignores the complexity of relationships. It is also deterministic as it assumes we are passive and allow conditioning to dictate our behaviour when in reality we have free will and may select a partner who need not be associated with pleasant stimuli.
An alternative explanation for the formation and maintenance was proposed by Thibault and Kelley who developed the social exchange theory. According to this theory relationships are seen as a balance sheet, whereby the couples calculate the rewards of being in a relationship minus the costs of maintaining that relationship. If the outcome is profitable in the sense rewards outweigh the costs, then the relationship is entered or maintained. However if an individual discovers the costs are exceeding the rewards they will seek to end the relationship.
How someone evaluates the rewards and costs will depend on their comparison level and their comparison levels of alternatives. What comparison level means are ones past experiences; this will dictate our level of satisfaction with a current relationship. Comparison level of alternative refers to the possible rewards that could be gained from being in another relationship or single i.e. freedom, more friendships etc. if the two comparison levels indicate we are making a loss the relationship is likely to end.
Evidence for this theory comes from naturalistic studies by Rusbult and Martz who found that victims of abusive relationships tend to remain in such households as they have poor economic alternatives and have invested a lot into the relationship, too much to lose by walking out. This explains why people remain in relationships when rewards are low. As this study was naturalistic it has more ecological validity and mundane realism than contrived lab experiments.
Though this theory may have received some empirical support the theory is still criticised for its inherent culturally bias stance. The theory is far more applicable to individualistic cultures in which the need for autonomy and self enhancement are apparent, whereas in collectivist cultures the emphasis is on pleasing others before pleasing oneself. As a result such couples are less likely to view their relationships as a balance sheet and more likely to see it as what they can do to help make the relationship work even if it means accepting unfair treatment.
Another flaw of this explanation is it paints a very selfish picture of relationships in which both parties are seeking to maximise their own benefits. This may not apply to all couples. Clark and mills distinguish between communal and exchange relationships. The former type focuses on mutual satisfaction and pleasing one another whereas the latter focus on exchanging rewards and costs. As a result we can assume that this theory only explains certain relationships and fails to account for a broader spectrum of relationships.
Finally the theory talks about abstract concepts of rewards and costs which are difficult to operationalise and measure. As a result the theory can not be objectively tested as what are rewards for some may not be for others, and what is deemed as a positive outcome for some may not be for others. As a result the theory lacks scientific rigor.
