EVENT-RELATED BRAIN POTENTIALS TO UNFAMILIAR FACES IN EXPLICIT AND IMPLICIT MEMORY TASKS

The purpose of this study was to investigate electrophysiological corr elates related to the recognition of repeated faces in the intact huma n by means of event-related brain potentials (ERPs). A group of young healthy adults performed a continuous face recognition task, in which 240 unfamiliar faces were flashed upon a computer screen with 80 of th e faces being repetitions. The subjects had to classify faces as previ ously seen and previously unseen faces. The concomitantly recorded ERP s from 19 scalp sites revealed a more positive going waveform for the correctly classified repeated faces beginning at about 280 ms (old/new effect). The same subjects performed a similar task with visually pre sented concrete nouns as stimuli. The old/new effect in this task show ed a similar distribution, amplitude and onset latency. It is thus con cluded that the old/new effect is not specific to the materials to be memorized. In contrast, the old/new effect in an implicit face repetit ion experiment (with the detection of famous persons being the task) s howed a different distribution. It is argued that the differential dis tribution might reflect the different requirements of the two tasks (e xplicit vs. implicit task). Recent interpretations of the old/new effe cts are discussed. (C) 1997 Elsevier Science Ireland Ltd.