Developmental changes in memory structure and precision alter the use of retrieved episodes during decisions for reward

How do we make efficient use of limited past experience to guide our present choices? Most widely-studied option evaluation strategies rely on knowledge accumulated across numerous repeated experiences. One possible alternative strategy in unfamiliar environments is episodic sampling, in which a decision maker retrieves a small number of memories of similar past decisions to estimate the value of present options. Such a strategy would be particularly useful for children and adolescents who, by virtue of their younger age, inherently have less experience to draw on than adults. On the other hand, the effectiveness of episodic sampling derives from its precision and context sensitivity—properties of episodic memory that continue to develop into adolescence and young adulthood. This raises a key question: do developmental changes in episodic memory produce changes in episodic sampling? To address this, 106 participants, ages 8-25, completed a two-day choice task that dissociated the influence of a single episodic memory on choice from the influence of multiple episodes sharing a common context. Across all ages, single evoked episodes biased choice, but only adults showed sensitivity to the broader evoked episodic context. Developmental gains in memory precision fully explained these differences, and paralleled a shift in the relationship of memory to forward planning. Together, these findings suggest that episodic memory guides decision making throughout development, but the character of its influence evolves as memory becomes more precise and richly structured.