Sensory deprivation or perceptual isolation is the deliberate reduction or removal of stimuli from one or more of the senses. Simple devices such as blindfolds or hoods and earmuffs can cut off sight and hearing, while more complex devices can also cut off the sense of smell, touch, taste, thermoception (heat-sense), and the ability to know which way is down. Sensory deprivation has been used in various alternative medicines and in psychological experiments. When deprived of sensation, the brain attempts to restore sensation in the form of hallucinations.

An isolation tank, sensory deprivation tank, float tank, float pod, float cabin, flotation tank, or sensory attenuation tank is a water filled, pitch-black, light-proof, soundproof environment heated to the same temperature as the skin.