Friends’ Personality Similarity and Its Association with Friendship Well-Being

Homophily on psychological characteristics is a common occurrence, yet recent evidence suggests that personality trait similarity among friends may be less common. Moreover, little is known about whether and how personality similarity—and perceptions of this similarity—among friends shapes how they feel about their relationships. In a study of 371 quads of friends (N = 1,484), we found personality similarity in most Big Five traits (except for extraversion), but perceived similarity was larger and more common than actual similarity for all personality traits. Response surface analyses found no evidence of similarity effects on friendship satisfaction across all traits and models. Rather, actor and partner effects (particularly perceived partner characteristics) of personality were more consistently associated with friendship satisfaction. Our findings contribute to the debate on similarity as a heuristic for friendship compatibility and enhance our understanding of whether and how friends’ personalities shape friendship well-being.