Psychological studies related to sensory and perceptual deprivation, immobilization, and isolation provide a body of literature that describes behavioral deficits occurring in experimental low-stimulus and meaningless environments. Specific hospital environments analogous to those used in the sensory deprivation experiments can also be used to identify patients who may be at high risk for maladaptive behavioral change. The studies offer extensive experimental evidence to support occupational therapy theory that a variety of meaningful tasks and stimuli are necessary to support the hospitalized person's adaptive behavior.