ABSTRACT
Recognition of social hierarchy is a key feature that helps us navigate through our complex social environment. Neuroimaging studies have identified brain structures involved in the processing of hierarchical stimuli, but the precise temporal dynamics of brain activity associated with such processing remains largely unknown. In this investigation, we used event-related potentials (ERPs) to examine the effect of social hierarchy on the neural responses elicited by dominant and nondominant faces. Participants played a game where they were led to believe that they were middle-rank players, responding alongside other alleged players, whom they perceived as higher or lower-ranking. ERPs were examined in response to dominant and nondominant faces, and low-resolution electromagnetic tomography (LORETA) was used to identify the implicated brain areas. The results revealed that the amplitude of the N170 component was enhanced for faces of dominant individuals, showing that hierarchy influences the early stages of face processing. A later component, the late positive potential (LPP) appearing between 350-700 ms, also was enhanced for faces of higher-ranking players. Source localisation suggested that the early modulation was due to an enhanced response in limbic regions. These findings provide electrophysiological evidence for enhanced early visual processing of socially dominant faces.
