Age differences on ERP old/new effects for emotional and neutral faces.

This study used event-related potentials (ERPs) to examine age differences in recognition memory for negative and neutral faces that systematically varied in facial expression during encoding and retrieval. During study, younger and older participants viewed negative and neutral faces and were asked to classify each facial expression. During test, half of the facial identities changed their facial expression, while the other half showed the same facial expression. Participants were asked to give old/new judgments to the depicted person. Four main findings were observed. First, when facial emotion did not switch from study to test, negative and neutral faces evoked spatially dissociable ERP old/new effects, independent of age. This suggests that different retrieval mechanisms contributed to successful recognition of negative and neutral faces in both age groups. Second, faces encoded with a negative expression evoked an early occipital old/new effect only in the young, perhaps suggesting superior memory for visual information. Third, faces retrieved with a negative expression evoked in both age groups an early parietal old/new effect, suggesting that negative emotion during retrieval facilitated memory access. Hence, in the early time latency in young adults both encoding-related and retrieval-related emotion effects contributed to face recognition memory, whereas in older adults encoding-related emotion effects were reduced and retrieval-related emotion effects were preserved. Finally, in the late time latency perceptual similarity between study and test faces modified or overruled encoding-related emotion effects in the young and retrieval-related emotion effects in both age groups, respectively.