Memory consolidation over multiple nights of sleep

This study aims to explore how sleep over multiple nights contributes to memory consolidation. Specifically, it will investigate existing conceptualizations of sleep’s role in declarative memory consolidation in humans: either as a prolonged transformative process, or as a single occurrence limited to a single night. Sleep’s effects on memory have been extensively studied (Smith, 1995), yet its role in preserving memories over long stretches of time (days, weeks, and months after learning) have been neglected, as typical experiments feature a single bout of sleep and often do not evaluate how memory consolidation is affected by naturalistic sleep processes occurring over successive nights (Rasch & Born, 2013). Participants will complete the study over roughly 11-14 days and attend three in-lab sessions within this period. The first in-lab session will set up participants with the wearable device (Fitbit Inspire 3), which will be continuously worn throughout both daytime and nighttime, as well as daily survey questionnaires, which will be sent daily in the mornings and evenings. After 2-4 days, they will return to the lab for a second session, where they will learn and memorize a set of 175 associable word pairs. For the next 8 days after the second session, participants will continue to wear the Fitbit and answer daily surveys, but also complete seven intermittent memory tests, each consisting of 25 word pairs. Finally, they will return for their last in-lab session, where they will be tested on the full 175 word pairs from the second session. The study will be conducted on the campuses of University of California, Irvine, as well as California Polytechnic State University (San Luis Obispo). Each site will run participants individually while using identical protocol guidelines, except for any details that may be site-specific (e.g., the room location where the study will take place). All in-lab sessions will occur in person, while participants will complete questionnaires and intervening memory tests (between in-lab sessions #2 and #3) remotely.