Description: Does sleep deprivation have harmful effects on cognitive functioning three days later? Stickgold, James, and Hobson (Nature Neuroscience, 2000) investigated this question by providing training to 21 volunteer subjects followed up by an initial test. The subjects were then divided into two groups: one group was deprived of sleep following the test, and the other group was permitted unrestricted sleep after the test. Both groups were then allowed as much sleep as they wanted on the following two nights. All subjects were then re-tested on the third day. This data set contains the improvement as measured by the difference between the two exam scores (second - first) and the sleep conditions imposed on the subject. Note that a negative value indicates a decrease in performance.