Perceptions of task difficulty predict cognitive effort for older adults.

This study examined age differences in effort devoted to completing cognitively demanding tasks. Fifty-two younger adults ages 18-30 years ( = 21.19) and 57 older adults ages 61-93 years ( = 76.56) completed a series of memory tests. Following each test, participants rated the test's difficulty and had their blood pressure measured. Effort was indexed by systolic blood pressure response (SBP-R) with greater increases in SBP-R reflecting more effort. Multilevel modeling was used to examine age differences in the intraindividual association between trial-level subjective task difficulty and trial-level effort. Results showed that increases in task difficulty were significantly related to decreases in SBP-R for the older but not younger adults, suggesting the older adults disengaged from the tests they perceived as highly difficult. Findings support Selective Engagement Theory (Hess, 2014), which suggests the perceived cognitive costs of completing difficult tasks may reduce older adults' motivation to engage in the tasks.