Abstract
Fast and accurate face perception is critical for successful human social interactions. Face perception declines with age both in behavioural and neural responses, although we do not yet understand why. Here, we tested the hypothesis that early brain mechanisms involved with face information processing are delayed in older participants. Using face detection - the most basic task for social interaction - we sampled visual information from faces (vs. noise) and reconstructed the features (mainly, the left eye) associated with detection behaviour in young (20-36 years) and older (60-86 years) adults. We then compared behavioural results to neural representations of face features revealed with simultaneously recorded EEG on the N170, an event-related potential associated with visual categorization. Whereas the right hemisphere N170 latency and amplitude represented the left eye in young participants, it was mostly amplitude that represented the eye with a 40 ms delay in older adults. Our results demonstrate that face processing speed declines in ageing with a delay in the early stages that process the visual information important for behaviour.
