The Effects of Partial
and Total Sensory Deprivation

By: Mark Bancroft, MA


Sensory deprivation facilitates the production of an altered state of consciousness through the reduction of extroceptive stimulation and/or motor activity [Tart, 1990]. Sensory deprivation functions in a similar manner as meditation; both reduce the perception of external stimulus. Whereas meditation accomplishes this through mental processes, sensory deprivation is a direct manipulation of the environment [Wallace & Fisher, 1991].

Partial sensory deprivation, including changes in patterns and relationships of sensory input, cause a state of relaxation conducive to an altered state. Awareness of one's surroundings remains and hypnagogic activity is likely to occur. A reduction of external stimuli allows an individual to focus inward due to the absence of attending to sensory input. Altering sensory perception allows for a focusing of the mind which in time produces an altered state. Relaxation, time to think without distractions, vivid imagery, and feelings of love and warmth are common experiences [Wallace & Fisher, 1991].

Technically, total sensory deprivation is very difficult to achieve [Auerbach, 1996]. However, in severe deprivation environments noticeable differences emerge. White-out conditions, prolonged isolation, or a highly structured environment intensifies the altered state experience. If brain stimulation from sensory inputs is eliminated or greatly altered the brain begins to "fill in"/compensate for the change. Hallucinations likely result; all perceptual experience is being drawn from internal sources. Loss of identity, difficulty meeting basic survival needs, apathy, and depression have been known to occur in a total sensory deprivation environment. Research subjects typically find the experience intolerable within only 4 days [Wallace & Fisher, 1991].

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Auerbach, L. Altered States of Consciousness, Lecture, Orinda, CA, (1996).

Tart, C.T. (1990). Altered States of Consciousness. (3rded.). New York: Harper Collins.

Wallace, B. & Fisher, L.E. (1991). Consciousness and Behavior. (3rd ed.). Needham Heights, MA: Allyn and Bacon.


Mark Bancroft, MA, CHT
Nevada City, CA