Shared Attention Amplifies the Neural Processing of Emotional Faces

Sharing an experience, without communicating, affects people’s subjective perception of the experience, often by intensifying it. We investigated the neural mechanisms underlying shared attention by implementing an EEG study where participants attended to and rated the intensity of emotional faces, simultaneously or independently. Participants performed the task in three experimental conditions: 1) alone (unshared), 2) simultaneously next to each other in pairs, without receiving feedback of the other’s responses (shared no feedback), and 3) simultaneously while receiving the feedback (shared with feedback). We focused on two face-sensitive ERP components: the amplitude of the N170 was greater in the shared with feedback condition compared to the unshared condition, reflecting a top-down effect of shared attention on the structural encoding of faces; while the EPN was greater in both shared context conditions compared to the unshared condition, reflecting an enhanced attention allocation in the processing of emotional content of faces, modulated by the social context. Behaviourally, we found a modulation of the perceived intensity for the neutral faces only, with an amplification of perceived neutrality in the shared feedback condition. Taken together, these results suggest that shared attention amplifies the neural processing of faces, regardless of the valence of facial expressions.