Brain potentials reflect access to visual and emotional memories for faces

Familiar faces convey different types of information, unlocking memories related to social–emotional significance. Here, the availability over time of different types of memory was evaluated using the time-course of P3 event related potentials. Two oddball paradigms were employed, both using unfamiliar faces as standards. The infrequent targets were, respectively, artificially-learned faces (devoid of social–emotional content) and faces of acquaintances. Although in both tasks targets were detected accurately, the corresponding time-course and scalp distribution of the P3 responses differed. Artificially-learned and acquaintance faces both elicited a P3b, maximal over centro-parietal sites, and a latency of 500 ms. Faces of acquaintances elicited an additional component, an early P3 maximal over frontal sites: with a latency of 350 ms. This suggests that visual familiarity can only trigger the overt recognition processes leading to the slower P3b, whereas emotional–social information can also elicit fast and automatic assessments (indexed by the frontal-P3) crucial for successful social interactions.