Estimation de la durée chez des sujets jeunes et âgés : rôle des processus mnésiques et attentionnels

Abstract

Summary : Estimation of duration in young and aged subjects : The role of attentional and memory processes. This paper questions the issue of age-related attentional and memory deficits in changes in time estimation with aging. Performances of younger (20-30 year-olds) and older adults (60-69 and 70-80 year-olds) were compared in two experiments, using tasks varying the attentional cost and memory operations required to perform the temporal task. The first experiment showed that reproductions of three target durations (5, 14 and 38 seconds) were as accurate and as consistent for older adults as for younger ones in a simple temporal task, for which subjects had only to evaluate time intervais during which they must count aloud. Nevertheless, older adults temporal reproductions were impaired (underestimated durations and variable temporal judgments) when they had to reproduce a time interval during which they had to share their attention between temporal processing and non-temporal processing (reading aloud digits). In the second experiment, reproduction and production performances were compared in the same double-task situation. The results showed that temporal judgments of older adults were compromised in the reproduction task, which required encoding and comparing two new durations in memory, whereas they were unimpaired in the production task, involving more simple memory operations (comparing an actual duration with a referent one stored in long term memory). These results are discussed in terms of joint effects of age-related attention and memory deficits. Keywords : aging, temporal estimation, memory and attentional processes, double-task.