Investigating how reward retroactively improves memory for associations and items: A registered report

Given we cannot remember all our experiences, it seems intuitive that we should prioritize events of consequence, like those that lead to a reward. However, rewards have had inconsistent effects on people's memory for preceding neutral experiences in experiments, raising questions as to whether our minds are equipped to remember adaptively. Here, we used online testing in a registered report to investigate whether rewards tend to retroactively enhance certain types of memories. Consistent with prior research and theories involving how dopamine modulates the hippocampus, we hypothesized that reward would retroactively enhance memory in a delay-dependent manner, emerging only after a period of consolidation. Crucially, we further predicted that this long-delay modulation of memory would be stronger for associative memory than for item recognition-a factor not previously considered despite its clear theoretical grounding. Our planned confirmatory analyses did not reveal any evidence for retroactive effects of reward on either associative or item memory. However, in exploratory analyses examining only individuals who were behaviorally sensitive to the reward manipulation, as measured by an independent task, we found evidence that reward retroactively enhanced associative-but not item-memory in a delay-dependent manner. This work sheds light on important open questions about the mechanisms by which reward retroactively enhances memory, elucidating the conditions under which this key aspect of adaptive memory emerges. (PsycInfo Database Record (c) 2026 APA, all rights reserved).