According to a report published in the February first issue of the journal Sleep, a short period of non-REM sleep during a daytime nap improves memory performance. However, this seems to be the case only when the person is quizzed on subjects he or she knows well.
Matthew A. Tucker, PhD, of the Center for Sleep and Cognition and the department of psychiatry at Harvard Medical School, and author of this study, says "These results suggest that there is a threshold acquisition level that has to be...
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