A sensory deprivation tank is a lightless, soundproof tank in which subjects float in salty water at skin temperature. They were first used by John C. Lilly in 1954 in order to test the effects of sensory deprivation. Such tanks are now also used for meditation, relaxation, and in alternative medicine. Isolation tanks were originally called sensory deprivation tanks. Other synonyms for isolation tanks include float tank, floating tank, floater tank, flotation tank’, REST tank, flotation baths, John Lilly tank and sensory attenuation tank.

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