Self-Other Mirroring in Personality Trait Structure

Humans use themselves as a reference when thinking about and perceiving others, but the extent to which individuals project their own personality structures onto others remains unclear. For example, does a person who is both extraverted and agreeable assume extraverted others are agreeable and introverted others are disagreeable? If so, do they apply this association when forming impressions from faces? To answer these questions, two preregistered studies (n=118, n=72) examined self-reported personality traits and judgments of others’ personalities, both conceptually and from faces. Both studies found evidence for self-projection of idiographic personality trait structure. Participants’ own trait associations predicted their perceived trait associations in others, which in turn predicted associations in face-based trait judgments. This effect persisted beyond simple assumed similarity of individual traits. The findings highlight how self-concept shapes social perception, with implications for person perception and social cognition. Self-other mirroring in personality structure provides insight into how people navigate the social world through the lens of their own experiences.