ALTERED STATE OF CONSCIOUSNESS [ASC]
The term ‘altered state of consciousness’ was coined by parapsychologist Charles Tart (b.1937), and it refers to a shift in the pattern of consciousness or normal waking state, for example during hypnosis, trance or dream state, when the conscious mind is subdued and the unconscious takes over. The operation of some psychic phenomena depends on being in an altered state of consciousness, but ASCs are difficult to study because of their subjective and internal nature, and because there is no universal state of consciousness from which to begin such a study.
States of consciousness take place in four levels of brainwave activity: beta, alpha, theta and delta. Beta level is complete waking consciousness. Alpha level is where material from the subconscious is available to the mind, as in meditation or daydreaming. The theta level is equivalent to light sleep, a state of unconsciousness in which one is vaguely aware of what is going on around one. The delta level is deep sleep.
Many ASCs can be differentiated, ranging from dreaming to trance to mystical states of consciousness, such as that experienced during a shamanic state. ASCs can occur spontaneously or can be induced through disciplines such as Yoga, Zen and other forms of meditation, prayer and magical techniques. They can also be induced through chanting, dancing, fasting, sex, hypnosis, trauma and sleep deprivation.
Orthodox science largely rejects the experiences and knowledge gained from ASCs, many of which are intensely spiritual in nature, but scientific research has been effective in the areas of dreams, meditation,
biofeedback and drug-induced states. Laboratory tests since the early 1950s on ASC-induced techniques such as relaxation, hypnosis and meditation have also been shown to enhance psi function, especially extrasensory perception (or ESP).
SOURCE:
The Element Encyclopedia of Ghosts and Hauntings: The Complete A–Z for the Entire Magical World: The Ultimate A-Z of Spirits, Mysteries and the Paranormal by Theresa Cheung