Common brain regions with distinct patterns of neural responses during mentalizing about groups and individuals

An individual has a mind; a group does not. Yet humans routinely endow groups with mental states irreducible to any of their members (e.g., "scientists hope to understand every aspect of nature"). But are these mental states categorically similar to those we attribute to individuals? In two fMRI experiments, we tested this question against a set of brain regions that are consistently associated with social cognition--medial pFC, anterior temporal lobe, TPJ, and medial parietal cortex. Participants alternately answered questions about the mental states and physical attributes of individual people and groups. Regions previously associated with mentalizing about individuals were also robustly responsive to judgments of groups, suggesting that perceivers deploy the same social-cognitive processes when thinking about the mind of an individual and the "mind" of a group. However, multivariate searchlight analysis revealed that several of these regions showed distinct multivoxel patterns of response to groups and individual people, suggesting that perceivers maintain distinct representations of groups and individuals during mental state inferences. These findings suggest that perceivers mentalize about groups in a manner qualitatively similar to mentalizing about individual people, but that the brain nevertheless maintains important distinctions between the representations of such entities.