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To sleep perchance to learn

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American



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From the Sleights of Mind archives.
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When I was 11 or 12, my geography teacher in Spain announced that every student needed to learn the capital of each country in the world, in addition to all the major geographical features of every continent: rivers, mountain ranges, capes, gulfs, and archipelagos. I stuck a large world map to my bedroom wall and tried to memorize the textbook in front of the poster, without success. I was out of options: I didn’t see how I could hold the copious, tedious details in my head. With the date of the test quickly approaching, panic set in, and then inspired me. I pulled out my tape recorder and read aloud as I recorded from the hated textbook for hours on end. I then played back the recording as I slept, for the remaining 3 nights leading to my date with doom. The outcome was disappointing. I wish I could tell you that I aced the exam, but alas, none of the information seemed to absorbed as I slept. Though I continued to struggle with geography through high school, I never attempted to study in my sleep again. So I guess I did learnsomething useful from my experience after all. High school procrastinators of future generations may be more fortunate, however. A recent study published in Nature Neuroscienceshows that humans can acquire entirely new information while they sleep. The researchers paired pleasant and unpleasant odors with different tones during sleep, and measured the subjects’ sniffs to tones alone when they were awake. Tones associated with pleasant smells produced stronger sniffs, and tones associated with disgusting smells produced weaker sniffs, despite the subjects’ lack of awareness of the learning process. So it may not help today, or even tomorrow, but perhaps this a first step towards fulfilling our dreams of learning through osmosis.

Susana Martinez-Conde is a professor of ophthalmology, neurology, and physiology and pharmacology at SUNY Downstate Health Sciences University in Brooklyn, N.Y. She is author of the Prisma Prize–winning Sleights of Mind, along with Stephen Macknik and Sandra Blakeslee, and of Champions of Illusion, along with Stephen Macknik.

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