Researchers have found that just 15 minutes of sensory deprivation can induce vivid hallucinations. This is a removal of external stimuli for your body’s senses, usually by muffling the ears and blindfolding the eyes so the recipient is unable to see or hear.
A study led by Oliver Mason of the University College London placed 19 volunteers inside a sensory deprivation room. This room contained absolutely no light, and was totally soundproof.
Many participants claimed they experienced “perceptual disturbances, paranoia, and anhedonia” after just 15 minutes of sensory deprivation. This supports a hypothesis made over 50 years ago, that symptoms of psychosis can be induced by sensory starvation.
The study concluded that the brain has an innate need for sensory patterns, creating them when none exist. The hallucinations themselves are an example of “faulty source monitoring”, wherein the brain misattributes the source of sensory input.
Sensory deprivation has been used as a form of torture. So called “white torture” involves long-term isolation that can cause the detainee to lose their sense of personal identity.
Not all forms of sensory deprivation are in relation to a negative experience. Isolation tanks are widely used for relaxation and meditation.
The lightless, soundproof tanks allow the user to float in salt water at skin temperature. This removes most sensations of touch, temperature and perception of gravity, as well as sight and sound.
Most therapeutic sessions in an isolation tank last between 60 to 90 minutes. They can offer a passive “clearing the mind” or active experience. Proponents of the isolation tank widely claim that it can even be used as a tool for enhanced problem solving and creative brainstorming.