Do opposites attract or do birds of a feather flock together?

Results show that couples were highly similar on attitudes and values; however, they had little or no above-chance similarity on personality-related domains such as attachment, extraversion, conscientiousness and positive or negative emotions. There is no evidence that opposites attract. What is most intriguing is that when the researchers assessed marital quality and happiness, they found that personality similarity was related to marital satisfaction, but attitude similarity was not. […]

“However, once people are in a committed relationship, it is primarily personality similarity that influences marital happiness because being in a committed relationship entails regular interaction and requires extensive coordination in dealing with tasks, issues and problems of daily living. Whereas personality similarity is likely to facilitate this process, personality differences may result in more friction and conflict in daily life,” say the authors.