The Asymmetric Effects of Aging on Between- and Within-Trial Timescales of Inhibition

Widespread cognitive decline in older adults has been hypothesized to stem from a fundamental deficit in inhibition, or the ability to ignore goal-irrelevant information. The extent to which inhibition operates across different timescales, however, has been under-explored. We introduce a novel cognitive task designed to assess both between- and within-trial inhibition using a common set of stimuli. Behavioral results from younger, middle-aged, and older adults (N=100; age range: 18-73) reveal significant age-related differences in between-trial inhibition, with older adults showing less efficient adaptation to rule changes compared to younger adults. Within-trial inhibition, requiring suppression of distractors within the current visual environment, appears to remain intact alongside normal aging. These findings will support the development of tools for the early detection of age-related cognitive decline, prior to subjective awareness of impaired daily functioning.