Sleep has many benefits that are widely known, but did you know it can also help you remember new information for long periods of time? In a 2019 article published in Science Advances, L. Himmer and colleagues at the University of Tübingen studied the interplay between rehearsal and sleep and their effect on memorization. They found that rehearsal of new information activates memorization and sleep preserves it.
Thirty-two subjects participated in the study. They were split randomly and evenly into the sleep group and the wake group. Both groups attended two learning sessions spaced 12 hours apart. The sleep group’s learning sessions occurred first at 7 p.m. to 11 p.m. and then again at 7 a.m. to 11 a.m. with the subjects being allowed to sleep through the night in between. The wake group’s learning sessions occurred at 7 a.m. to 11 a.m. and then again at 7 p.m. to 11
p.m., however, they were instructed not to sleep in between sessions.
During the sessions, 28 nouns were presented on a screen with each word being presented on a different color background. The subjects were asked to remember the word and the color of the background. This process was
repeated seven times over the course of the session with the word order randomized each time. After each recurrence, the subjects were asked to recount the words and subsequent background colors they could remember. As predicted, the subjects remembered more words and colors after each repetition and there was no significant difference found between the two groups of subjects in this regard.
During the second learning session, new words and colors were added to the list of nouns the subjects had been instructed to remember. The same seven-repetition process was repeated the same as in the first session. There was no
difference to be found between the two groups in the recall of the new words and colors. However, when recounting old words and colors learned during the first session, the sleep group did significantly better than the wake group. Based on the results, the researchers concluded that rehearsal initiates memorization and sleep preserves it.
One of the brain’s most fundamental abilities is to form and preserve memories. However, it would appear that those abilities are impacted by sleep, or lack thereof. The next time you plan to pull an all-nighter before an exam, maybe stop, reconsider, and add sleep as the last part of your study regimen.