The present study examined the effects of thought suppression on sleep-onset mentation. It was hypothesized that the decrease of attentional control in the transition to sleep would lead to a rebound of a suppressed thought in hypnagogic mentation. Twenty-four young adults spent two consecutive nights in a sleep laboratory. Half of the participants were instructed to suppress a target thought, whereas the other half freely thought of anything at all. To assess target thought frequency, three different measures were used in (...) the wake state and mentation reports were repeatedly prompted by a computer at sleep onset. In support of the hypothesis, results revealed a reversal of target thought frequency at sleep onset: Participants instructed to suppress reported fewer target thoughts than did controls before falling asleep, but more target thoughts afterwards. (shrink)

Several theories claim that dreaming is a random by-product of REM sleep physiology and that it does not serve any natural function. Phenomenal dream content, however, is not as disorganized as such views imply. The form and content of dreams is not random but organized and selective: during dreaming, the brain constructs a complex model of the world in which certain types of elements, when compared to waking life, are underrepresented whereas others are over represented. Furthermore, dream content is consistently (...) and powerfully modulated by certain types of waking experiences. On the basis of this evidence, I put forward the hypothesis that the biological function of dreaming is to simulate threatening events, and to rehearse threat perception and threat avoidance. To evaluate this hypothesis, we need to consider the original evolutionary context of dreaming and the possible traces it has left in the dream content of the present human population. In the ancestral environment human life was short and full of threats. Any behavioral advantage in dealing with highly dangerous events would have increased the probability of reproductive success. A dream-production mechanism that tends to select threatening waking events and simulate them over and over again in various combinations would have been valuable for the development and maintenance of threat-avoidance skills. Empirical evidence from normative dream content, children's dreams, recurrent dreams, nightmares, post traumatic dreams, and the dreams of hunter-gatherers indicates that our dream-production mechanisms are in fact specialized in the simulation of threatening events, and thus provides support to the threat simulation hypothesis of the function of dreaming. Key Words: dream content; dream function; evolution of consciousness; evolutionary psychology; fear; implicit learning; nightmares; rehearsal; REM; sleep; threat perception. (shrink)

The studies reported in the following articles are aimed at providing a comprehensive, detailed, and quantitative picture of cognition in human dreaming. Our main premises are that waking, REM sleep, and non-REM sleep represent physiologically distinct and identifiable brain states and that the differences between waking, REM, and NREM mentation reflect these physiological differences. We have studied dreams at a formal level of analysis and, in these papers, have studied the specific dream properties of emotions, bizarre transformations, scene shifts, and (...) plot coherence, in adults and 4- to 10-year-old children, as part of a larger effort to map state-dependent mental phenomena back onto the varying neurobiological processes that must underlie them. We believe that such efforts will enhance our understanding not only of dreaming and its neurophysiological substrates, but also of the cognitive processes that dreaming shares with other unusual mental states. (shrink)

Sleep researchers in different disciplines disagree about how fully dreaming can be explained in terms of brain physiology. Debate has focused on whether REM sleep dreaming is qualitatively different from nonREM (NREM) sleep and waking. A review of psychophysiological studies shows clear quantitative differences between REM and NREM mentation and between REM and waking mentation. Recent neuroimaging and neurophysiological studies also differentiate REM, NREM, and waking in features with phenomenological implications. Both evidence and theory suggest that there are isomorphisms between (...) the phenomenology and the physiology of dreams. We present a three-dimensional model with specific examples from normally and abnormally changing conscious states. Key Words: consciousness; dreaming; neuroimaging; neuromodulation; NREM; phenomenology; qualia; REM; sleep. (shrink)

Sleep researchers in different disciplines disagree about how fully dreaming can be explained in terms of brain physiology. Debate has focused on whether REM sleep dreaming is qualitatively different from nonREM (NREM) sleep and waking. A review of psychophysiological studies shows clear quantitative differences between REM and NREM mentation and between REM and waking mentation. Recent neuroimaging and neurophysiological studies also differentiate REM, NREM, and waking in features with phenomenological implications. Both evidence and theory suggest that there are isomorphisms between (...) the phenomenology and the physiology of dreams. We present a three-dimensional model with specific examples from normally and abnormally changing conscious states. Key Words: consciousness; dreaming; neuroimaging; neuromodulation; NREM; phenomenology; qualia; REM; sleep. (shrink)

Bear Suppression Inventory (WBSI), was I'ound to correlate with n>casurcs of obsessional thinking and depressive and anxious al'lect, t pridic( signs «I' clinical «hscssion ainong individuals prone (oward «h»c»»i«n >I (hi>>king, (« predict depression tive (h (», and to predict I''iilurc «I' electr«dermal responses to habituate am«ng pci>pic having emotional thoughts. The WBSI was inversely correlated with repression as assessed by the Repression-Sensitization Scale, and so tap» a trait that i» itc unlike rcprc»si«n:is traditi«n;illy c«nccivcd.

��People spent 5 min before sleep at home writing their stream of thought as they suppressed thoughts of a target person, thought of the person, or wrote freely after mentioning the person. These presleep references generally prompted people to report increased dreaming about the person. However, suppression instructions were particularly likely to have this in- fluence, increasing dreaming about the person as measured both by participants’ self-ratings of their dreams and by raters’ coding of mentions of the person in written (...) dream reports. This effect was observed regardless of emotional attraction to the person. (shrink)

The accessibility of suppressed thoughts was compared with the accessibility of thoughts on which Ss were consciously trying to concentrate. In Experiment I, Ss made associations to word prompts as they tried to suppress thinking about a target word (e.g., house) or tried to concentrate on that word. Under the cognitive load imposed by time pressure, they gave the target word in response to target-related prompts (e.g., home) more often during suppression than during concentration. In Experiment 2, reaction times for (...) naming colors of words were found to be greater under conditions of cognitive load when Ss were asked to suppress thinking of the word than under conditions of no cognitive load or when Ss were asked to concentrate on the word. The results support the idea that an automatic search for the suppression target increases the accessibility of the target during.. (shrink)