Previously we reported a three-factor structure for hallucinations accompanying sleep paralysis . These earlier analyses were, however, based on retrospective accounts. In a prospective study, 383 individuals reported individual episodes online providing further evidence for the three-factor structure as well as clearer conceptually meaningful relations among factors than retrospective studies. In addition, reports of individual episodes permitted a more fine-grained analysis of the internal structure of factors to assess predictions based on the hypothesis that a sensed or felt presence is (...) a core experience affecting other SP hallucinations. Results were generally consistent with this hypothesis. In particular, associations among, and temporal stability of, sensory hallucinations were largely explained by their common association with FP. The findings are consistent with REM initiation of a threat activated vigilance system with pervasive effects on the SP experience and suggest a potential model for the thematic organization of nightmares and dreams more generally. (shrink)

Hypnagogic and hypnopompic experiences (HHEs) accompanying sleep paralysis (SP) are often cited as sources of accounts of supernatural nocturnal assaults and paranormal experiences. Descriptions of such experiences are remarkably consistent across time and cultures and consistent also with known mechanisms of REM states. A three-factor structural model of HHEs based on their relations both to cultural narratives and REM neurophysiology is developed and tested with several large samples. One factor, labeled Intruder, consisting of sensed presence, fear, and auditory and visual (...) hallucinations, is conjectured to originate in a hypervigilant state initiated in the midbrain. Another factor, Incubus, comprising pressure on the chest, breathing difficulties, and pain, is attributed to effects of hyperpolarization of motoneurons on perceptions of respiration. These two factors have in common an implied alien ''other'' consistent with occult narratives identified in numerous contemporary and historical cultures. A third factor, labeled Unusual Bodily Experiences, consisting of floating/flying sensations, out-of-body experiences, and feelings of bliss, is related to physically impossible experiences generated by conflicts of endogenous and exogenous activation related to body position, orientation, and movement. Implications of this last factor for understanding of orientational primacy in self-consciousness are considered. Central features of the model developed here are consistent with recent work on hallucinations associated with hypnosis and schizophrenia. (shrink)

A 'sensed presence' often accompanies hypnagogic and hypnopompic hallucinations associated with sleep paralysis. Qualitative descriptions of the sensed presence during sleep paralysis are consistent with the experience of a monitoring, stalking predator. It is argued that the sensed presence during sleep paralysis arises because of REM-related endogenous activation of a hypervigilant and biased attentive state, the normal function of which is to resolve ambiguities inherent in biologically relevant threat cues. Given the lack of disambiguating environmental cues, however, the feeling of (...) presence persists as a protracted experience that is both numinous and ominous. This experience, in turn, shapes the elaboration and integration of the concurrent hallucinations that often take on supernatural and daemonic qualities. The sense of presence considered here is an 'other' that is radically different from, and hence more than a mere projection of, the self. Such a numinous sense of otherness may constitute a primordial core consciousness of the animate and sentient in the world around us. (shrink)