Distinct neural correlates of social categories and personality traits.

Does the processing of social category-related versus trait-related information generate a different pattern of brain activation? In this fMRI study, we compared the processing of behaviors performed by a member of a social category versus an individual, both possessing similar personality traits. Based on previous behavioral studies we predicted that the processing of social category-related information would recruit more activation in brain areas related to mentalizing than individual trait-related information. Participants read sentences describing behaviors performed by a member of a social category (of which the stereotype involves a given trait) or by an individual possessing the same trait. These behavioral sentences varied on both valence (positive versus negative) and consistency (consistent versus inconsistent) with regard to the social category or trait. The results revealed that social category-related behavioral information showed more activation in mentalizing areas (medial prefrontal cortex, anterior temporal lobe, bilateral temporo-parietal junction, posterior cingulate cortex) than trait-related information. This increased activation is interpreted in terms of the impact of autobiographical memories, greater variance among members of social categories than individual traits, a higher construal level (i.e., abstractness), and larger perceived group size. Additionally, inconsistent as opposed to consistent information showed more activation in the right temporo-parietal junction and left lingual gyrus.