Sleep and retrieval practice both strengthen and distort story recollection

Abstract

Over time, memories lose episodic detail and become distorted, a process with serious ramifications for eyewitness identification. What are the processes contributing to such transformations over time? We investigated the roles of post learning sleep and retrieval practice in memory accuracy and distortion, using a naturalistic story recollection task. Undergraduate students listened to a recording of the “War of the Ghosts”, a Native American folktale, and were assigned to either a sleep or wake delay group, and either a retrieval practice or listen-only study condition. We found higher accuracy after sleep compared to wake in the listen-only condition, but not in the retrieval practice condition. This effect was driven by participants in the wake, retrieval practice condition showing superior memory compared to the wake, listen only condition. A similar pattern was found for memory distortion, with both sleep and retrieval practice being associated with more inferences of non-presented, but story related information, compared to the wake, listen only condition. These findings suggest both sleep and retrieval practice contribute to narrative memory stabilization and distortion. This paper is part of the Festschrift in honor of Dr. Robert Stickgold. The open access publishing fee for this paper was contributed by the Psychiatry Department at BIDMC.