Sensory deprivation is the purposeful removal of one or more sensory stimuli. Alternative forms of medicine may prescribe sensory deprivation for decompressing from our society’s need to be digitally connected, which can result in overstimulation of several senses. Sensory overload is the opposite of sensory deprivation and is associated with urbanization, crowding, mass media, technology, and noise.
Sensory deprivation has also been used in experimental psychology to study stress in humans. Examples of sensory deprivation include chamber restricted environmental stimulation therapy, an isolation pool, or a sensory deprivation tank. Less inclusive tools have been developed to isolate only one sensory stimulus at a time. For instance, to remove visual stimuli, a blindfold or hood will be placed over the eyes and/or head of an animal or person. Hooding raptors and birds of prey allows their handler to have better control of the bird, as the bird relaxes. Blindfolding a person can help improve his or her sleep. Similarly, headphones, earplugs, or earmuffs can be placed over or in a person’s ears to remove external sound stimuli.
Short-term sensory deprivation (about 30 minutes up to 24 hours) has shown to be successful in producing rest in people and is often used in meditation. Furthermore, it has been reported to produce a sense of relaxation. However, if sensory deprivation is extended or forced upon an individual, it generally results in increased anxiety, hallucinations, depression, stress, and abnormal thoughts. Thus, sensory deprivation can have both positive and negative effects, depending on how it is being used, either as a way to help calm animals or humans, or as a practice of inhumane treatment.
Restricted Environmental Stimulation Therapy
The two most common forms of sensory deprivation are (1) chamber restricted environmental stimulation therapy—where a person lies on a bed in a completely dark and soundproof room for 24 hours, and (2) flotation restricted environmental stimulation therapy—where a person lies in an enclosed, water-filled tub with the water at skin temperature for 60 minutes. Both of these therapies remove light and sound stimuli as well as reduce touch sensations. In chamber restricted environmental stimulation therapy the person is allowed to use the bathroom, eat, and drink but goes back to lie on the bed. The individual is not encouraged to sleep, as this therapy is to help the person to focus on the lack of stimuli in the surroundings. For the flotation restricted environmental stimulation therapy, the tank is filled with water and enough Epsom salts to allow the person to float easily. The size of the tank is small so that it is restrictive and difficult for the floating person to turn over. This extended weightlessness in a dark, enclosed tank often results in changes of brainwave activity as well as relaxation for the person. Thus, some people use this therapy to help them with solving a problem in their work or life or to increase their mental creativity.
Sensory Deprivation and Experimental Psychology
Prior to formal studies of experimental isolation, only anecdotal observations were reported on solitary sailors, polar inhabitants, prisoners, and hermits. These reports show that isolation induces similar symptoms of mental illness, such as experiencing hallucinations or depression. However, wide variations were observed between people. Some were able to handle the isolation whereas others had extreme reactions.
In the early 1950s, experimental psychology researchers began sensory deprivation or perceptual isolation studies. Over the next few decades, Zuckerman and colleagues (1964) studied the different aspects of sensory deprivation, including sensory restriction, social isolation, and confinement. Additionally, they looked at sex differences between men and women. They found that women generally showed more effects than men, particularly in increases in anxiety and feelings of surrealism.
Jennifer L. Hellier
See also: Auditory System; Discriminative Touch; Olfactory System; Taste System; Touch; Vibration Sensation; Visual System
Goldberger, Leo. (1966). Experimental isolation: An overview. American Journal of Psychiatry, 122(7), 774—782.
Stronks, H. Christiaan, Amy C. Nau, Michael R. Ibbotson, & Nick Barnes. (2015). The role of visual deprivation and experience on the performance of sensory substitution devices. Brain Research, 1624, 140—152.
Zuckerman, Marvin. (1964). Perceptual isolation as a stress situation: A review. Archives of General Psychiatry, 11, 255—276.