Sensory Deprivation

The process of psychic development generally entails learning to refocus attention from the outer world of sensory input and directing attention inward in some form. One popular form is meditation, in which the person consciously withdraws attention from sensory data. Various attempts to readjust the environment to reduce sensory input have been made. Lights can be dimmed, a quiet location selected, a comfortable posture assumed, and breathing regulated.

The heightened blocking of normal sensory input has been found to result in hallucinations and vivid fantasies. Such a heightened blockage can be attained by placing a person in a sensory neutral environment. In the Ganzfeld setting, the eyes and ears are covered, and a sensory neutral environment is created with blue light and white noise.

An even more intense experience is provided by the isolation tank, in which an individual can float in water at a controlled temperature in a soundproof, lightproof chamber. While such experiments may be exhausting and affect mental process in an unstable individual, they can throw light on personality disorders and apparent paranormal experiences. An apparatus called the Witches' Cradle, devised by Robert E. L. Masters and Jean Houston of the Foundation for Mind Research, has been developed to study heightened sensory deprivation.