Reward does not modulate forgetting in free recall tests

Reward is thought to attenuate forgetting through the automatic effect of dopamine on hippocampal memory traces. Here we report a conceptual replication of previous results where we did not observe this effect of reward. Participants encoded eight lists of pictures and recalled picture content immediately or the next day. They were informed that they could gain monetary reward for recalling the pictures, with the level of reward indicated through the frame surrounding the picture. Reward was manipulated both within and across lists. Bayesian statistics found moderate evidence for the null hypothesis that reward does not modulate forgetting in human free recall.