Influence of reward motivation on human declarative memory

• Motivational relevance prioritizes information in memory based on reward value.
• Reward guides attention, energizes behavior, and enhances memory consolidation.
• Reward value can generalize from one stimulus to similar or associated stimuli.
• Coordinated hippocampal and reward system activity boosts memory integration.
• How learned reward associations affect subsequent learning remains unknown.

Motivational relevance can prioritize information for memory encoding and consolidation based on reward value. In this review, we pinpoint the possible psychological and neural mechanisms by which reward promotes learning, from guiding attention to enhancing memory consolidation. We then discuss how reward value can spill-over from one conditioned stimulus to a non-conditioned stimulus. Such generalization can occur across perceptually similar items or through more complex relations, such as associative or logical inferences. Existing evidence suggests that the neurotransmitter dopamine boosts the formation of declarative memory for rewarded information and may also control the generalization of reward values. In particular, temporally-correlated activity in the hippocampus and in regions of the dopaminergic circuit may mediate value-based decisions and facilitate cross-item integration. Given the importance of generalization in learning, our review points to the need to study not only how reward affects later memory but how learned reward values may generalize to related representations and ultimately alter memory structure.