Rest now, recall later
THROW out the ginkgo. Forget mnemonics. New research suggests there’s a simple way to lock in new info: Sleep on it.
Researchers at Harvard Medical School in Boston asked 48 subjects to learn a list of 20 pairs of words and then tested them 12 hours later on their recall of the pairs. Some subjects were taught the words at 9 a.m., while others learned the words at 9 p.m. and then went to sleep.
The results, to be reported this week at a neurology meeting, were a wake-up call for all-night exam crammers: Subjects in the sleep group remembered 12% more words from the list than subjects who learned the words at 9 a.m.
Half of both groups also were asked to learn a second list of words just before testing, to study the effect of distracting information on recall. Yet again, subjects in the sleep group did better, recalling 44% more words than subjects in the nonsleep group.
Lead author and neurologist Dr. Jeffrey Ellenbogen believes the memory boost could be caused by the brain replaying daytime information during sleep, similar to a rehearsal. And he has some advice for sleep-deprived students.
“I tell my students that you might do OK if you cram for an exam all night long, but don’t expect that memory to last very long,” he says in an e-mail. “Sleep is important for making memories stable and strong.”
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