Medial prefrontal dissociations during processing of trait diagnostic and nondiagnostic person information

Previous research has suggested that perceivers spontaneously extract trait-specific information from the behaviour of others. However, little is known about whether perceivers spontaneously engage in the same depth of social-cognitive processing for all person information or reserve such processing specifically for information that conveys diagnostic clues about another person's dispositions. Moreover, a question remains as to whether the processing of such nondiagnostic information can be affected by perceivers' explicit goal to consider another's dispositions or not. To examine processing of diagnostic and nondiagnostic social information as a function of perceivers' explicit social-cognitive goals, participants underwent functional magnetic resonance imaging (fMRI) scanning while performing social (impression formation) or non-social orienting tasks using statements that conveyed either diagnostic or nondiagnostic information about the target's personality traits. Replicating two earlier studies, results identified a region of dorsal medial prefrontal cortex (mPFC) that was preferentially activated by impression formation. Interestingly, no difference between trait-diagnostic and nondiagnostic information was observed when participants had the explicit goal of forming an impression, but a substantial effect of diagnosticity emerged when task instructions oriented them away from considering the target as a social agent. These results suggest that trait-nondiagnostic information is not subject to spontaneous social-cognitive processing, but that such processing may nevertheless occur when perceivers have the explicit goal to use that information to form an impression of a target.