Taking a brief nap after studying — instead of participating in other activities — can significantly increase retention of the information just learned, according to a new study at Saarland University.
“Even a short sleep lasting 45 to 60 minutes produces a five-fold improvement in information retrieval from memory,” says Professor Axel Mecklinger, Ph.D.
“The control group, whose members watched DVDs while the other group slept, performed significantly worse than the nap group when it came to remembering the word pairs. The memory performance of the participants who had a power nap was just as good as it was before sleeping, that is, immediately after completing the learning phase.”
During the study, the researchers focused mostly on the role of the hippocampus, the part of the brain where memories are consolidated. In the hippocampus, previously learned information is transferred into long-term memory storage.
“We examined a particular type of brain activity, known as ‘sleep spindles,’ that plays an important role in memory consolidation during sleep,” explains Sara Studte, a graduate biologist specializing in neuropsychology. A sleep spindle is a short burst of rapid oscillations in the electroencephalogram (EEG).
The greater the number of sleep spindles in a person’s brain, the better he or she will remember newly acquired information. New information is essentially given a label, making it easier to recall that information at some later time.
“We suspect that certain types of memory content, particularly information that was previously tagged, is preferentially consolidated during this type of brain activity,” says Mecklinger.
In an effort to rule out the possibility that the study subjects only recall the learned items due to a feeling of familiarity, the researchers used the following trick: participants were asked to learn not only 90 single words, but also 120 word pairs, in which the word pairs were essentially meaningless.
“A word pair might, for example, be ‘milk-taxi.’ Familiarity is of no use here when participants try to remember this word pair, because they have never heard this particular word combination before and it is essentially without meaning. They therefore need to access the specific memory of the corresponding episode in the hippocampus,” said Mecklinger.
“A short nap at the office or in school is enough to significantly improve learning success. Wherever people are in a learning environment, we should think seriously about the positive effects of sleep.”
Source: Saarland University