8 Ss were presented verbal stimuli (numbers) during different stages of sleep. 15 sec. after each presentation they were awakened and asked if they had heard anything. If not, they were presented a multiple-choice test including the stimulus and another 3 numbers. It was concluded that: (1) even during stages 3 and 4 some perception of verbal stimuli is possible during sleep; (2) there is a progressive blurring of perception from stage 1 and REM to stages 3 and 4; (3) some forms of learning seem to be possible during sleep beyond a drowsy state, e.g., associations of words, but perceptual distortions make extremely unlikely the assimilation of complex verbal materials. It was also noticed that most verbal stimulations tended to produce a lightening of sleep as measured by the EEG. Based on the responses of some Ss the possibility of some form of subliminal perception during sleep was also raised.
An axiomatization of multiple-choice test scoring
