Event-related potential evidence for age-related differences in attentional allocation during a source monitoring task

Event-related potentials (ERPs) were recorded while older and younger adult s were engaged in a source monitoring task. After studying a list of words, participants were presented with a recognition test during which some of t he new words were repeated, rendering them as familiar as the study words. Instructions at test indicated whether the goal was to select the previousl y studied words or the repeated test items. Behaviorally, the younger adult s were less likely to make source monitoring errors. ERPs, averaged only fo r correct trials, indicated that younger adults produced late positivities of greatest amplitude in response to whichever word type was designated as target irrespective of its familiarity. The ERPs of the older adults were g enerally less differentiated and their late positivities greater for recent ly repeated words irrespective of target designation. These results suggest that source monitoring in young adults is facilitated by their ability to allocate and withdraw attention from stimuli on the basis of task relevance rather than familiarity alone, and that this attentional flexibility decli nes with age.