Four experiments were performed to test the behavioral effects of REM deprivation on rats. Two studies of avoidance learning showed that shuttle avoidance and runway avoidance were unaffected by REM deprivation. REM deprivation produced an enhancement of activity, and the addition of periodic shock demonstrated a failure of adaptation for REM‐deprived subjects. These data were interpreted as indicating that REM deprivation produces motivational effects on rat behavior and that electric shock‐induced pain and REM deprivation interact to change activity patterns. It was concluded that the findings of the present experiment can be explained most parsimoniously in terms of increased sensitivity of REM‐deprived subjects to environmental stimulation.

Spaced practice (20 min. work, 24 hr. rest) was more efficient for 4 trials than massed practice (20 min. work, 90 sec. rest) in the learning of alpha enhancement by undergraduate women ( Ns = 10) While the spaced group doubled their production of alpha, the massed group demonstrated almost no improvement.

We attempted to modify sleep and dreaming through the administration of various posthypnotic suggestions. Subjects were 17 male undergraduates who were selected for high susceptibility to hypnosis. After two adaptation nights, 5 subjects were given a dream-deprivation suggestion, 8 were given a suggestion of dream-facilitation, and the remaining 4 subjects were administered a neutral posthypnotic suggestion. Subjective dream reports were dramatically affected in the predicted directions. Electrophysiological changes were also noted in certain subjects, although these results were not nearly as consistent as the subjective data. The dream-deprivation group had significantly more Stage 1 sleep than the other two groups; and certain of these subjects had much less REM sleep. Schroetter (1911) and Nachmansohn (1925) demonstrated that nocturnal dream reports may be influenced by hypnotic suggestion. These investigators noted that morning recall of dreaming was often consistent with presleep suggestions administered during hypnosis. In recent years, this basic observation has been replicated and amplified by other investigators (Barber, Walker, &Hahn, 1973;Stoyva, 1965;Tart, 1964;Tart & Dick, 1970). According to Tart (1965), "Posthypnotic suggestion seems to be the most powerful and precise method for affecting dream content, although its use is restricted to a minority of subjects" (p. 85).Stoyva (1965) reported that subjects' dream reports were in accordance with administered suggestions. He also noted thatpresleephypnotic suggestions resulted in a reduction of REM sleep time. The intensity of this "shortening" effect was related to the number of elements in the dream suggestion, but the emotional tone of the suggested topic did not appear to influence the degree of reduction. Hypnotic relaxation without suggestion failed to reduce REM time. Barber, Walker, and Hahn (1973) gave subjects a presleep suggestion to dream about the assassination of President Kennedy. Au-

A sleep questionnaire was administered to a group of experienced meditators and to an appropriate control group. Meditators reported that they awakened in the morning more rested than nonmeditators. :\1editators also reported more dreaming and a more positive quality in their dream content.

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