Opposites Attract...but how much? Does you "ying" really match their "yang"?

In a study published in the Proceedings of the National Academy of Sciences in July of 2003, researchers quizzed 978 heterosexual residents of Ithaca, N.Y., between the ages of 18 and 24. First, the participants rated the importance of 10 attributes of a long-term partner, and then rated themselves on the same scale. When the results were tallied, self-perception was more likely to match mate perception. This conclusion was: "In Western society, humans use neither an 'opposites-attract' nor a 'reproductive-potentials-attract' rule in their choice of long-term partners, but rather a 'likes-attract' rule based on a preference for partners who are similar to themselves across a number of characteristics."