Why opposites rarely attract

But this isn’t quite the end of the story. Psychologist Arthur Aron believes that, while similarity is important, there may be some situations in which it can actually undermine attraction. He argued that people also have a need to grow and expand the self – and that one reason why we form relationships with others is because we can assimilate some of the qualities of our partners, which promotes such growth.

The implication is that we will be attracted to others who offer the greatest potential for self-expansion – and someone who is similar in values and traits provides much less potential for growth than someone who is different. So, the model ends up predicting that dissimilarity can sometimes be attractive, especially if you believe that there is a good possibility a relationship will develop. Aron’s research using the phantom stranger technique would seem to support this idea.

But of course, the picture gets more complicated when we consider how couples actually behave in real life. For example, when couples discover that they disagree strongly on some topic they often bring their attitudes into “alignment” with each other – becoming more similar to each other over time.