Aging shifts the relative contributions of episodic and semantic memory to decision-making.

Healthy aging is accompanied by well-characterized shifts in memory systems: episodic memory tends to decline with age while semantic memory remains relatively intact, with some knowledge domains strengthening. Beyond reflecting on the past, these distinct memory systems often guide decisions about the future. Yet how such age-related memory shifts influence simple value-based choices remain understudied. Here, younger (18-24 years) and older (61-75 years) adults completed a card game in which they could use task-relevant episodic memories to maximize the number of points they earned. Critically, they could also use task-irrelevant semantic memories to guide their choices. Both younger and older adults successfully used episodic memory to make decisions, but older adults did so less reliably than younger adults. Further, while younger adults strategically suppressed task-irrelevant semantic memories when a relevant episodic memory could be used, older adults used semantic memory to guide their decisions regardless of the relevance of episodic memory. We provide evidence that declining inhibitory control may play a role in how older adults arbitrate between competing memory sources when making decisions. These effects are consistent with the literature on age-related shifts in memory and cognitive control systems and add to a growing body of work on how episodic memories inform reinforcement learning and value-based decision-making. Our findings highlight how patterns of age-related memory differences can have consequences for value-based choices, which has implications for other types of decision-making, from the economic to the mundane. (PsycInfo Database Record (c) 2022 APA, all rights reserved).