False recognition in a verbal memory task: an event-related potential study

Brain potentials were recorded from 15 healthy young subjects during the pe rformance of a word recognition task. During the study phase, subjects had to intentionally memorise a series of words. These words were presented aga in together with the same number of new words in a following test phase whe re the instruction was to discriminate between repeated words and new words . We compared event-related potentials (ERPs) evoked by correctly identifie d repeated words (hits) and ERPs evoked by incorrectly classified new words (false alarms). Although both types of words were thought to be repeated t he ERPs indicated differences between these two conditions starting at abou t 450 ms after the stimulus onset. These differences were mostly pronounced over frontal scalp locations but occurred also over parietal scalp locatio ns (false alarms produced significantly more negative going ERPs than hits) . We interpret that frontal and parietal brain areas show greater activatio n during false recognition because of a more intensive search for item repr esentations. (C) 2000 Elsevier Science B.V. All rights reserved.