Aging and effort expenditure: The impact of subjective perceptions of task demands

Abstract

Engagement in cognitively demanding activities has a positive impact on cognitive health in older adults. Previous work, however, has suggested that the costs associated with engagement increase in later life and influence motivation. We examined how subjective perceptions of these costs varied with age and influenced task engagement. The following questions were of specific interest: (a) Are there age differences in subjective perceptions of cognitive costs? (b) What is the impact of these perceptions on engagement? We tested 39 older (ages 65-84) and 37 younger (20-42) adults on a working memory task. Systolic blood pressure responsivity (SBP-R; reflective of effort) and subjective perceptions of task difficulty were assessed. We found that age was associated with an increase in the perceptions of cognitive costs, and that these subjective perceptions had a stronger impact on older adults' engagement than on that of younger adults. More important, this impact was specific to subjective perceptions of cognitive costs. The results provide further support for the hypothesis that increased costs associated with cognitive engagement influence older adults' willingness to engage cognitive resources, and that these costs in part reflect subjective perceptions that are independent of objective task demands. (PsycINFO Database Record

Figure 1

Mean performance on the LNS task as a function of age and objective task difficulty.

Figure 2

Mean ratings by age group and objective task difficulty for each TLX subscale. The old group is represented by the dashed line.

Figure 3

Estimated SBP-R as a function of objective task difficulty (i.e., memory-set size).

Figure 4

Estimated SBP-R as a function of composite TLX score (represented in terms of SDs from the mean). Note that objective task difficulty was not controlled for in calculating these estimates.