Sleep selectively and durably enhances real-world sequence memory

Sleep is thought to play a critical role in the retention of episodic memories. Yet it remains unclear whether and how sleep actively transforms memory for specific experiences. More generally, little is known about sleep′s effects on memory for multidimensional real–world experiences, both overnight and in the days to months that follow. In an exception to the law of forgetting, we showed that sleep actively and selectively improves retrieval of a one–time real–world experience (a controlled but immersive art tour) – specifically boosting memory for the order of tour items (sequential associations), but not perceptual details from the tour (featural associations). This above–baseline increase in sequence memory was not evident after a matched period of wakefulness. Moreover, the sleep–induced advantage of sequence over featural memory grew over time up to one–year post–encoding. Finally, overnight polysomnography showed that sleep–related memory enhancement was associated with the duration and neurophysiological hallmarks of slow–wave sleep previously linked to neural replay, particularly spindle–slow wave coupling. These results suggest that sleep serves a crucial and selective role in enhancing sequential organization in episodic memory at the expense of specific details, linking sleep–related neural mechanisms to the transformation and enhancement of memory for complex real–life experiences. ### Competing Interest Statement The authors have declared no competing interest.