The next time you think about studying all night with your face in a book, think about this: Your brain will work better if you sleep on that book instead.
Shut-eye may be a good performance-boosting strategy, according to a new study presented at the Society for Neuroscience Conference in Atlanta.
Scientists from Harvard University studied nearly 100 college students to find out whether sleep can improve memory.
They divided the students into two groups and told each student to memorize several lists of related words -- such as bed, sheet, and pillow or sill, glass, and pane -- as they were read aloud.
The first group tried to memorize the lists at 9 a.m. while the second group tried to memorize the lists at 9 p.m.
The memory test came 12 hours after the students had first heard the words.
So, daytime learners were tested at 9 p.m. while night learners were tested at 9 a.m.
But the students who first learned the words during the evening got a good night's rest before facing their memory test the next morning.
Each group was asked to write down all the words that they could remember. Researchers found that the students who studied the lists at 9 p.m. and got some sleep remembered more words than the students who were tested after staying awake throughout the day.
The Phenomenon of Remembering Incorrectly
However, the students who got some sleep also recalled some words that were not on the lists.
From a list of words including bed, sheet and pillow, a student may incorrectly remember the word "sleep" or form a false memory for the word "window" in a list including sill, glass and pane.
The students were remembering words that were associated with the ones that they had actually heard.
Scientists call this phenomenon of incorrectly remembering something that didn't happen a "false memory."
False memories are not all that unusual. It's similar to a feeling you have when you think you're sure that something happened -- until someone proves you wrong.
Then you realize that your false memory was just an idea very closely related to something that happened in reality.
Sleep Plays a Role in False Memories
The students who snoozed before testing had more of these false memories than their friends who did not sleep.
This is the first time scientists have seen that sleep plays a role in false memories -- and researchers are excited about the discovery.
The finding suggests that the brain is hardly asleep when the rest of the body is.
"Sleep is not a passive state where we lay around and lose productivity, but an active process during which the brain is integrating information," said Dr. Christoph Nissen, sleep researcher and postdoctoral fellow at the Western Psychiatric Institute in Pittsburgh.
According to this study, the brain is engaged in a sort of wordplay while the body is asleep.
This finding suggests that a learning process occurs during sleep that has a lot to do with language and what words mean, says Dr. Lawrence Epstein, past president of the American Academy of Sleep Medicine, and medical director of Sleep Health Centers in Boston.
Our brain forms links between our memories for these words to help us store information in a way that is meaningful to us.
During sleep, "our brain is writing a summary," said Dr. Robert Stickgold, study author and associate professor of psychiatry at Harvard Medical School and Beth Israel Deaconess Medical Center.
When the brain awakes, it may recall words from this summary even though those words weren't part of the original exercise.
Forget the All-Nighters
Sleep may do interesting things to our memories, but not sleeping can wreak havoc on the brain and on the body.
Experts say that getting enough sleep is vital to our overall health.
It plays a role in immune function, emotional regulation, and other processes like the ability to concentrate.
There's no substitute for serious studying, but a good night's sleep may prove to be more helpful than scientists previously thought.
"People who study and then sleep recall things better than people who stay up all night studying," Epstein said.