Experimental Studies in ‘Hypnotic’ Behaviour: Suggested Deafness Evaluated by Delayed Auditory Feedback*

Delayed auditory feedback (DAF) was used to assess the objective consequences of suggested deafness. Forty‐two women students were randomly assigned to three groups of fourteen subjects. Group A received suggestions of deafness subsequent to a standardized 15 min. hypnotic induction procedure; Group B received suggestions of deafness under waking conditions; Group C served as a control. Suggestions of deafness, given with or without a preceding hypnotic induction procedure, were effective with the majority of subjects in eliciting subjective reports of altered auditory perception. However, subjects claiming partial or total ‘subjective deafness’ responded to the DAF with stuttering, mispronunciations, increased vocal intensity and slowed rate of speaking in the same way as the controls who heard normally.