Does overnight memory consolidation support next-day learning?

Abstract

Sleep supports memory consolidation and next-day learning. The Active Systems model of consolidation proposes that sleep facilitates a shift in the memory retrieval network from hippocampus to neocortex in service of long-term storage. Accordingly, overnight consolidation may support efficient next-day learning. We tested this hypothesis across two preregistered behavioural experiments. In both experiments, participants learned a set of word pairs and recall was assessed before and after a 12-h delay containing overnight sleep or daytime wakefulness. Participants then learned and were immediately tested on a new set of word pairs. Word pair retention was better after the delay of sleep than wakefulness, suggesting a benefit of sleep for memory consolidation, but there was no sleep-related learning advantage for the new set of word pairs. Sleep-associated consolidation was not associated with next-day learning in our preregistered analyses, although a significant positive relationship with learning did emerge in an exploratory analysis that accounted for performance at pre-sleep recall. Taken together, our findings provide exploratory evidence that overnight consolidation may be linked to new learning, with pre-sleep retrieval performance influencing the magnitude of this relationship.