Repeated extrinsic rewards following retrieval practice facilitate later memory

The anticipation of extrinsic reward facilitates memory formation. However, it is unclear how reward following memory retrieval influences the information that is retrieved and later remembered. Here, we conducted four behavioral experiments in which we manipulated retrieval practice reward delivery. Across all experiments, participants studied word-image pairs and then completed two rounds of retrieval practice, followed by a final recognition test. Participants made vividness judgments during retrieval practice, and in three of four experiments, each response had a 50% chance of yielding positive feedback. We find that repeated rewards following retrieval practice facilitate later memory. Items that are practiced with low vividness are remembered worse than items that are not practiced. Together, these results suggest that the benefits of both retrieval practice and reward may depend on the strength of the memory retrieved.