We’ve all heard how “opposites attract." But we're also told that “birds of a feather flock together."
The fact that both of these adages have been passed down for so long suggests that the role of similarity in relationships is not a simple matter.
Most research indicates that we do prefer to affiliate with others who are similar to us—who share our values and interests.1,2,3 But some claim that when it comes to personality traits, we may be most interested in complementarity. This means that for some traits, similarity is most desirable, but for others, we prefer someone who is our opposite.
The type of complementarity that has received the most attention from researchers examines two traits: affiliation (warm and friendly vs. cold and hostile) and control (dominant vs. submissive). According to this theory, we will prefer someone who is similar to us on affiliation (warm people like other warm people, and cold people like other cold people) and opposite on dominance (dominant people pair off with submissive people).4 On the other hand, we might expect that everyone, regardless of their own personality, would prefer positive traits in others. For example, even cold people should still prefer to be with someone who is warm.