There are two theories of the formation of romantic relationships, which are the reward/need satisfaction theory by Byrne and Clore (1970) and the similarity theory also by Byrne and Clore with Smeaton (1986). The similarity theory promotes liking. It suggests that we are attracted to people with similar personalities and attitudes to us and that we first sort potential partners for dissimilarity avoiding those whose personality or attitudes appear too different from our own. This suggests that we form relationships due to similarity. Research to support this theory can be seen by Caspi and Herbener (1990). They found that married couples with similar personalities tend to be happier then couples with less similar personalities. This suggests that similarity is important and often the rule for long term relationships.
The similarity theory is based on the social approach which fails to consider the cognitive thought process, meaning that the theory assumes that we form relationships based upon similarities. Another criticism is of the determinist view this theory takes. This means that it takes away a person’s ability to make their own decisions therefore it is deterministic. The theory does not consider not consider that often some couples who are completely opposite in personality and attitudes. This means that theory cannot account for everyone. However the theory is widely recognised as its principles are used on dating websites which match up partners according to how similar they are to each other. Yoshida (1972) pointed out that this represents only a very narrow view of factors important in relationship formation as similarity of self-concept, economic level and physical condition being equally important.
This research is backed up by Speakman et al (2007) who found that people often choose partners with similar levels of body fat. This shows that similar personality and attitudes are not the only factors in the formation of relationships. The reward/need satisfaction theory is a far better explanation of the formation of romantic relationships. This theory suggests that we are attracted to people who we find satisfying or gratifying to be with. The theory is also based on the principles of operant conditioning as we seek rewarding stimuli and avoid punishing stimuli, and classical conditioning due to attraction through association.
Also we like people who are associated with pleasant events such as a holiday. The theory suggests that we go into relationships because the presence of some individuals is directly associated with reinforcements which makes them more attractive to us. Byrne and Clore also suggested that we like people who are associated with pleasant events and that the balances of positive and negative feelings are crucial in relationships. This means that where the positive feelings outweigh the negative feelings a relationship is more likely to develop and succeed whereas where the negative feelings outweigh the positive feelings are likely to fail.
This theory can be criticised for not explaining abusive relationships as these types of relationships still form despite the partner receiving punishing stimuli from that relationship. It also does not account for cultural and gender differences in the formation of relationships. For example, Lott (1994) suggested that in many cultures women are more focused on the need of others rather than receiving reinforcements. Also this research used a survey and is therefore subjected to social desirability bias.