A Multimodal Analysis of Sustained Attention in Younger and Older Adults

Age-related cognitive decline has been attributed to processing speed differences, as well as differences in executive control and response inhibition. However, recent research has shown that healthy older adults have intact, if not superior, sustained attention abilities compared to younger adults. The present study used a combination of reaction time (RT), thought probes, and pupillometry to measure sustained attention in samples of younger and older adults. The RT data revealed that, while slightly slower overall, older adults sustained their attention to the task better than younger adults, and did not show a vigilance decrement. Older adults also reported fewer instances of task-unrelated thoughts and reported feeling more motivated and alert than younger adults, despite finding the task more demanding. Additionally, older adults showed larger, albeit later-peaking, task-evoked pupillary responses (TEPRs), corroborating the behavioral and self-report data. Finally, older adults did not show a shallowing of TEPRs across time, corroborating the finding that their RTs also did not change across time. The present findings are interpreted in light of processing speed theory, resource-depletion theories of vigilance, and recent neurological theories of cognitive aging.