How task demands influence time-based prospective memory performance in young and older adults

Abstract

Prospective memory performance as a measure of everyday cognitive functioning is of increasing importance for developmental research. However, comparisons of studies on prospective memory development in adults reveal essential differences. Although some studies report no age effects, others find age effects of widely varying magnitudes. We suggest that differences in these findings on prospective memory performance can be explained by an age by task interaction (i.e., large amounts of cognitive load imposed by time-based prospective memory tasks disproportionally penalise older adults who possess fewer cognitive resources). We explored our hypothesis in a study with 90 young adults (M = 24.0 years) and 75 older adults (M = 69.0 years) by manipulating the overall cognitive processing demands of the prospective task situation. We varied the cognitive load of the background task while holding constant the time-based prospective memory task. Results indicate that the effects of increased overall processing demands strongly influence older adults’ performance. Results are discussed within the framework of capacity explanations of cognitive ageing that focus on the role of working memory resources in monitoring processes.