Reward Enhances Memory via Age-Varying Online and Offline Neural Mechanisms across Development

The effect of choice on memory across development

Numerous studies have demonstrated the role of making choices as an internal motivator to improve performance, and recent studies in the domain of memory have focused on adults. To chart the developmental trend of the choice effect on memory, we conducted a series of seven experiments involving children, adolescents, and young adults. Participants (N = 512) aged 5 to 26 years performed a choice encoding task that manipulated the opportunities to choose and then took a memory test. Using different types of experimental materials and corroborated by a mini meta-analysis, we found that the choice effect on memory was significant in childhood and early adolescence but not significant in late adolescence and early adulthood. The developmental changes were statistically significant, particularly evident during the transition from early to late adolescence. These findings suggest that the internal value of choice decreases across development and contributes to our understanding of developmental differences in the role of choice in memory.

Continuously changing memories: a framework for proactive and non-linear consolidation

The traditional view of long-term memory is that memory traces mature in a predetermined 'linear' process: their neural substrate shifts from rapidly plastic medial temporal regions towards stable neocortical networks. We propose that memories remain malleable, not by repeated reinstantiations of this linear process but instead via dynamic routes of proactive and non-linear consolidation: memories change, their trajectory is flexible and reversible, and their physical basis develops continuously according to anticipated demands. Studies demonstrating memory updating, increasing hippocampal dependence to support adaptive use, and rapid neocortical plasticity provide evidence for continued non-linear consolidation. Although anticipated demand can affect all stages of memory formation, the extent to which it shapes the physical memory trace repeatedly and proactively will require further dedicated research.

Reward-motivated memories influence new learning across development

Previously rewarding experiences can influence choices in new situations. Past work has demonstrated that existing reward associations can either help or hinder future behaviors and that there is substantial individual variability in the transfer of value across contexts. Developmental changes in reward sensitivity may also modulate the impact of prior reward associations on later goal-directed behavior. The current study aimed to characterize how reward associations formed in the past affected learning in the present from childhood to adulthood. Participants completed a reinforcement learning paradigm using high- and low-reward stimuli from a task completed 24 h earlier, as well as novel stimuli, as choice options. We found that prior high-reward associations impeded learning across all ages. We then assessed how individual differences in the prioritization of high- versus low-reward associations in memory impacted new learning. Greater high-reward memory prioritization was associated with worse learning performance for previously high-reward relative to low-reward stimuli across age. Adolescents also showed impeded early learning regardless of individual differences in high-reward memory prioritization. Detrimental effects of previous reward on choice behavior did not persist beyond learning. These findings indicate that prior reward associations proactively interfere with future learning from childhood to adulthood and that individual differences in reward-related memory prioritization influence new learning across age.