The Non-Recall of Material Presented during Sleep

A list of ten one-syllable nouns was repeated as many times as possible to nine Ss during an eight-hour sleep period. A continuous EEG recording during the presentation of the training material was used to determine the sleep level at that time. The stimulus material was turned off as soon as cyclical activity within the alpha range was observed. The experimental Ss did not do significantly better than the control group in selecting the words on the training list of 50 words. Nor did they choose the training words any more frequently than they chose an equivalent list of untrained words. There was some indication that words presented during a period of deep drowsiness can be retained, but this was significant only when the S was also able to give an immediate response to the material being presented. The effects of sleep level and the importance of continuous EEG monitoring while presenting the training material are discussed in their relation to recall. It is concluded that material presented a number of times during sleep (using an EEG criterion) cannot be subsequently recalled. (Author)