A Short Nap Can Improve Memory Retention by 5-Fold

A short nap that lasts from 45 to 60 minutes can yield a 5-fold improvement in memory retention, according to a recent study.

“Many studies have shown that sleep improves memory performance, and that even short naps during the day are beneficial. Certain physiological components of sleep such as spindles and slow-wave-sleep are thought to be particularly important for memory consolidation,” said the study’s authors.
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“The aim of this experiment was to reveal the role of naps for hippocampus-dependent associative memory (AM) and hippocampus-independent item memory (IM) alongside their corresponding ERP old/new effects,” they said.

For the study, researchers had 40 participants learn single words (90) and word-pairs (120) before performing an IM test and an AM test at baseline.

Researchers allowed 1 group of 20 participants to nap for 90 minutes while the control group watched DVDs.

Afterward, researchers had both groups perform a final IM test and an AM test to evaluated the learned information.

The study showed that AM performance decreased for the control group, but remained stable for the nap group. Those who napped between 45 to 60 minutes after the learning task,performed 5 times better at remembering word pairs.

The IM performance waned for both groups.

Further, researchers discovered that the greater number of sleep spindles present in the electroencephalogram—what researchers used to measure the brain activity of the napping group—the stronger the individual’s memory of a subject remains.

The investigators noted that a short nap significantly boosts associative memory, which they defined as the ability to remember the link between unrelated items.

The complete study is published in the February issue of Neurobiology of Learning and Memory.

-Michelle Canales Butcher

Reference:

Studte S, Bridger E, Mecklinger A. Nap sleep preserves associative but not item memory performance. 2015 February [epub ahead of print] doi: 10.1016/j.nlm.2015.02.012.