Harvard Medical School researchers conducted a study in which people were taught to type a sequence of keys on a computer keyboard as quickly and accurately as possible. A group trained in the morning and then re-tested 12 hours later were able to improve their performance by about two percent. However, the performance of those trained in the evening and re-tested 12 hours later, after a good night’s sleep, improved far more significantly — an average of 20 percent improvement in their performance. The amount of improved performance was directly correlated with the amount of Stage 2 sleep an individual was able to receive, particularly late in the night. “Motor skill learning is maximized when we get a full night’s sleep,” said Matthew Walker, Harvard Medical School clinical fellow in psychiatry and senior author of the paper. “You could say that modern life’s erosion of sleep time is seriously short changing your brain of valuable learning potential.” The study was reported in the July 3, 2002, edition of Neuron. The study was supported by funds from the National Science Foundation and National Institutes of Health.