Sensory Deprivation

Sensory deprivation (aka perceptual isolation) is the purposeful stifling of sensory stimuli (either partially or in full), usually of multiple senses. Sensory deprivation is usually achieved with simple methods – blindfolds, hoods, earmuffs, and dark rooms – but can also employ devices for preventing smell, touch, taste, heat or cold, and even gravity. Another device used to enhance sensory deprivation is flotation tanks (body temperature watertanks filled with salt water (high epsom salt- magnesium sulphate). Flotation tanks were invented by the John Lilly, who conducted groundbreaking psychological studies in Sensory Deprivation during the early 1950s. Lilly has been described as an American physician, neuroscientist, psychoanalyst, philosopher and “psychonaut.” His research on the nature of consciousness using isolation takes were the inspiration for the films Altered States and Day of the Dolphin.

Sensory deprivation has been used for a variety of purposes starting with psychological experiments, but also as alternative medical therapy and torture.

Classic effects of sensory deprivation


Sensory deprivation flotation tank

In a classic psychological sensory deprivation study 19 healthy volunteers were placed, for 15 minutes, in a sensory-deprivation room that was devoid of light and sound. Subjects reported seeing visual hallucinations, feeling paranoia (sensing an evil presence) and even depressed mood – at times at the same level of symptoms of psychosis.

When the brain is deprived of normal sensory information it experiences in our environment, it often tries to superimpose its own patterns – this is called “faulty source monitoring,” the brain misidentifies the source of what it is experiencing and tries to construct perception (which may manifest as hallucinations). From my reading psychologist are unsure why some minds unravel so spectacularly when deprived of sensory input.

Time dilation
One interesting effect of a specific type of sensory deprivation (long periods living underground without daylight and clocks) causes ‘time-shifting.’ Although the reasons are indeterminate, research has shown that in darkness most people adjust to a 48-hour cycle: 36 hours of activity followed by 12 hours of sleep. NASA is very interested in the effects of sensory deprivation and time dilation. A couple of experiments demonstrate the results:

“In 1961, French geologist Michel Siffre led a two-week expedition to study an underground glacier beneath the French Alps and ended up staying two months, fascinated by how the darkness affected human biology. He decided to abandon his watch and “live like an animal”. While conducting tests with his team on the surface, they discovered it took him five minutes to count to what he thought was 120 seconds.”

“A similar pattern of ‘slowing time’ was reported by Maurizio Montalbini, a sociologist and caving enthusiast. In 1993, Montalbini spent 366 days in an underground cavern near Pesaro in Italy that had been designed with Nasa to simulate space missions, breaking his own world record for time spent underground. When he emerged, he was convinced only 219 days had passed. His sleep-wake cycles had almost doubled in length.”

Sensory deprivation as torture
Extreme isolation and sensory deprivation can have severe toll on emotional and mental health – sometimes permanent. Prisoners in solitary become withdrawn in a short period of time, and demonstrate hypersensitive to sights and sounds, paranoid, and more prone to violence and hallucinations. Prisoners often show paranoid psychosis after prolonged solitary confinement that is profound enough to require medical treatment. The effects and impact of such deprivation are well known and have been used as a form of torture, but psychologist consider the practice cruel and counterproductive. Children are especially vulnerable to sensory deprivation, which can and does impact developmental advancement.

Therapy – Alternative medicine
Considering the devastating impact of long term sensory deprivation, it is surprising that short term sessions are now being used as alternative medicine therapy (primary as stress management, muscle tension, chronic pain, hypertension, and rheumatoid arthritis) in the form of flotation. There’s no scientific proof that such treatments work, but anecdotal evidence suggest that many people find the experience very restful.

Web applications
None likely.

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