Complementarity Definition

ComplementarityDo birds of a feather flock together? Do opposites attract? These questions have been examined extensively within the domain of attraction, but less emphasis has been placed on the similarity versus complementarity in ongoing relationships. Complementarity means that partners are different in ways that enable them to fit or work together well.

Many studies have supported the idea that we are initially attracted to those who are similar to us in personality, looks, and interests. The question then becomes whether this desire for the other to be like us would result in happier, more satisfying relationships in the longer term. The answer to this question appears to be “not always.” While we do appear to prefer those with personality traits similar to ours, complementarity between partners’ needs and roles within the relationship also predict satisfaction in relationships. Complementarity does not refer to opposites per se but characteristics, needs, or roles that partners hold that are different but work together to create a cohesive whole.

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Take the issue of roles. If both you and your partner love to cook but refuse to clean (i.e., similarity in roles), your quality of living may be compromised until such time as one of you cannot take it anymore and cleans up. If the same partner is left to deal with the mess each time, this “giving in” may cause resentment to grow. With complementarity, however, you could each specialize in a unique role (e.g., if you enjoy cooking and your partner enjoys housecleaning, you have unique but complementary roles in the household, and everything gets done by the person who enjoys it more), or you could alternate roles over time (e.g., “I’ll cook if you’ll wash the dishes, then tomorrow we’ll switch”). Research has shown that these kinds of complementarity increase satisfaction and lower conflict in both dating and marital relationships.

What evidence do we have that this complementarity actually exists in relationships? Individuals in both dating and marital relationships report outperforming their partners in areas that are important to their own self-concept (e.g., “Sports are important to me. I play better than my partner”) and underperforming in areas that are not important to the self (e.g., “Sports are not important to me. I do not play as well as my partner”). These individuals also reported outperforming their partner in areas that did not matter to the partner and underperforming in areas that were relevant to the person they were involved with.

This suggests that while similarity appears to play a strong role in initial attraction generally and more specifically in terms of personality traits, complementarity of needs and roles also appear to play a strong role in relationship continuation and success in ongoing relationships.


  1. Pilkington, C., Tesser, A., & Stephens, D. (1991). Complementarity in romantic relationships: A self-evaluation maintenance perspective. Journal of Social and Personal Relationships, 8(4), 481-504.
  2. Schmitt, D. (2002). Personality, attachment, and sexuality related to dating relationship outcomes: Contrasting three perspectives on personal attribute interaction. British Journal of Social Psychology, 41, 589-610.