The effects of varying auditory input on schizophrenic hallucinations.

The present report is of the effect of variations of auditory input on hallucinatory experiences in seven schizophrenic patients. Nine experimental conditions, each of two minutes' duration were compared with a control condition. At the end of each period subjects were required to rate the duration, loudness, and clarity of hallucinations during that time. Experimental conditions varied according to the amount of structure present in the material and in its attention-commanding properties. One condition required the active monitoring of material presented and resulted in the greatest decrease in hallucinatory experiences. For the passive conditions, findings were broadly consistent with predictions, indicating that it is not stimulation per se, but rather the extent to which structure is present and attended to, that is important in determining the occurrence of hallucinatory phenomena.