Mate assortment in dating and married couples

Dating and married couples show comparable levels of assortment for physical traits. Married couples, however, are more assorted on psychological traits. It is argued that both dating and married couples initially assort on physical similarity, but that couples who are similar on psychological traits are more likely to marry. Physical traits are apparently critical in initial partner selection; psychological traits are more important for long-term relationships. There is little evidence that couples become more similar in psychological traits over time, implying that existing similarities are due to initial assortment.