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