Parsing inhibitory and mnemonic contributions to age-related decline in cognitive flexibility

Cognitive flexibility (CF)-the ability to shift between mental sets as goals change-declines across the adult lifespan. Competing accounts attribute this decline either to deficits in specific underlying processes such as inhibition or memory or to broader challenges in coordinating these processes. Efforts to identify the root cause of CF decline by comparing performance across targeted tasks, however, have produced mixed findings. This work presents a unified task that simultaneously engages (a) CF through rule switches requiring participants to encode new task-relevant sets and inhibit outdated ones and (b) item-level inhibition of perceptual distractors. Eighty-six adults aged 18-73 completed the task. Accuracy analyses revealed asymmetric age effects across operations: learning following rule switches declined with age, whereas inhibition of perceptual distractors remained stable. Computational modeling further revealed that reduced rule-switching ability across age was primarily driven by reduced memory precision for task-relevant information, rather than impaired inhibition of outdated rules. These findings support a specific deficit account whereby age-related decline in memory precision has downstream effects on CF. (PsycInfo Database Record (c) 2026 APA, all rights reserved).