SOME EXPERIMENTS CONCERNING THE EFFECTS OF SLEEP ON MEMORY

Abstract

ABSTRACT A series of studies was conducted in an attempt to explore the effect of sleep on consolidation of memory traces. In each study, Ss were shown words shortly after each of several awakenings during the night. After the words were shown, the Ss were either permitted to return to sleep immediately (S treatment) or were kept awake for 5 min working on a psychomotor task (A treatment). Memory for the words was tested the following morning. Under the (S) treatment condition, retention was positively related to the time taken to return to sleep after the word was shown. It was possible to replicate previous findings that retention is better in the (A) than in the (S) treatment. However, this treatment effect was found only if the psychomotor task was conducted under testlike conditions and only if the Ss pronounced the words during the stimulus presentation. If the task was presented to the S as a game, or if pronunciation was delayed until after the presentation ended, merely keeping the S awake in the (A) treatment did not improve retention. The phenomena observed do not appear to be easily interpreted as an effect of sleep on memory.