It matters who you are: biography modulates the neural dynamics of facial identity representation

Recognizing a face and identifying a person are essential to our life. Here, we tested how person knowledge modulates face processing. Participants were allocated randomly into two groups, and they were familiarized with faces, associated with artificial biographies. Crucially, while the faces were identical to both groups, the associated biographies were reversed for the two groups. We estimated cross-participant, leave-one-participant-out pairwise identity (ID) classifications from the EEG data within the two face-biography association groups and compared them to the those performed across the groups. We observed that face-biography knowledge associations led to robust familiarity signals from 300 ms, and to rapidly emerging ID representations starting from 80 ms. Importantly, the shared associations within participant groups led to a longer and stronger ID representation over left anterior and right posterior regions when compared to cross-group comparisons. The direct comparison of within and cross-group classifications showed that an early stage of ID representation (around 250-350 ms), is modulated by face-biography associations. Our findings suggest that person recognition memory modulates visual face ID representation already at an early processing stage and provides new insights into the spatiotemporal dynamics of how conceptual, biographical knowledge modulates familiar face representation.