Previous studies examining sustained attention ability in older adults have yielded inconsistent results: age-related decline in studies using traditionally formatted tasks (TFT), in which subjects have to respond to rare targets, and preservation in studies using Go/No-Go tasks, in which subjects have to withhold response to rare targets. The purpose of this study was to examine whether these discrepancies could be explained by a differential use of automatic and controlled processes according to age. To that end, we used two versions of the same task differing in response mode (TFT, Go/No-Go), and the event-related potential (ERP) technique. The within-task comparison first revealed that older adults exhibited a vigilance decrement in the TFT SART, while their performance actually improved in the Go/No-Go SART. Secondly, in both tasks, ERP results notably evidenced increased P2s and non-target P3s in older adults, components related to the allocation of attentional resources. Altogether, our results suggest that in both tasks older adults adopted a controlled processing mode, which resulted in opposite effects on performance according to the nature of the task.
Keywords: Aging; SART; Time-on-task; Vigilance.
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