Sleep more, improve recollection. A new study from U. Notre Dame reached this conclusion after finding that going to sleep shortly after learning new information is most valuable for recalling the information in the future.

Jessica Payne, a Notre Dame psychologist who specializes in sleep studies, studied 207 subjects who regularly slept at least six hours per night. The study was focused on how much information a subject remembers after learning it directly before sleeping.

Participants studied either related or unrelated word pairs in the morning or evening, at 9 a.m. or 9 p.m., and would be tested on their ability to remember the word pairings 30 minutes, 12 hours or 24 hours later. Some of the word pairs were semantically related and some pairs were completely unrelated.

This studied declarative memory, which is a person’s ability to remember facts and specific knowledge.

“Following a 12-hour retention interval containing a night of sleep or a day of wakefulness, overall recall was superior in subjects who slept,” the study stated.

These findings were similar at the 24-hour retest. At this point all of the subjects had received a full night’s rest, but researchers found that subjects who went to sleep shortly after learning the words remembered better than subjects who did not.

“Our study confirms that sleeping directly after learning something new is beneficial for memory,” Payne told Science Daily. “What’s novel about this study is that we tried to shine light on sleep’s influence on both types of declarative memory by studying semantically unrelated and related word pairs.”

Jude Kehoe, a nurse at U. Oregon’s Health Center, stressed the importance of sleep for students. She discouraged irregular sleep patterns for studying because the body does not learn as efficiently with irregular sleep. The body can also only make up two hours of sleep, she said.

“Our brain does all of this filing when you are asleep and the REM sleep helps students learn better,” Kehoe said. “If students would study during the day and then sleep eight hours, they would remember the information much better. When you don’t have sleep, it causes a stress reaction to go off in your body, with negative cascading effects.”

Payne encouraged studying directly before sleeping for the greatest recall in the morning.

“Since we found that sleeping soon after learning benefited both types of memory, this means that it would be a good thing to rehearse any information you need to remember just prior to going to bed,” Payne told Science Daily. “In some sense, you may be ‘telling’ the sleeping brain what to consolidate.”