...Ullman's vigilance theory of dreaming posits that during REM sleep, the dreamer scans not only the intemal environment but also those aspects of the external environment that he or she can perceive by anomalous means. During sleep, hunters and gatherers were vulnerable to attack. Contemporary human beings respond to symbolic threats, rather than to physical dangers. Yet vigilance still operates, and REM sleep, perhaps because of its linkage to a primordial danger sensing mechanism, provides a favorable state for anomalous communication.
Ullman's theory is not incompatible with J.A. Hobson's (1988) proposal that, during REM sleep, the brain is activated internally by random neural firing from lower brain centers that stimulate higher brain centers. For Hobson, the dream results from a knitting together of these neurologically evoked memories and images. I would propose that the random nature of this neurological firing provides an opportunity for anomalous effects to operate, either influencing portions of the cortex that are stimulated or the images that are evoked.
Significant ESP was associated with strong shifts of attention in other experiments at Maimonides Medical Center. One clairvoyance experiment involved a variety of architectural environments; another involved electrosleep, a device whose electrical current induced relaxation and visualization; still another experiment utilized hypnotic dreams (Krippner, 1975, Chapter 4). The eminent psychologist and parapsychologist Gardner Murphy (1966) had predicted that psi activation would be more often associated with a shift from one state of consciousness to another rather than with a steady state. The Maimonides experiments indicated that he was correct.