EXPERIMENTAL STUDIES IN “HYPNOTIC” BEHAVIOR: PHYSIOLOGIC AND SUBJECTIVE EFFECTS OF IMAGINED PAIN

Abstract

Forty-eight female subjects, selected as responsive to suggestions, were randomly assigned to 3 "waking" groups and one "hypnosis" group with 12 to each group. In the first part of the experiment, all subjects were tested on subjective and physiologic responses to a pain-producing stimulus (water at 2[degree] C applied to a limb for one minute). Suggestions of "analgesia" or reduced pain responsiveness were not administered under either the "hypnosis" or "waking" conditions. The "hypnotized" group and the "awake" groups did not differ significantly in subjective or physiologic responses to this stimulus: both "hypnotized" and "waking" subjects showed increased heart rate, increased frontalis muscle tension and reduced skin resistance, and reported that the stimulus was experienced as painful. In the second part of the experiment, subjects in the "hypr nosis" group and in one "waking" group were instructed to imagine that they were again receiving the pain-producing stimulus, a second "waking" group again received the actual pain-producing stimulus, and a third "waking" group received an innocuous stimulus. The major findings were: Instructions to imagine the painful stimulus were more effective with the "hypnotized" subjects than with the "awake" subjects in eliciting subjective reports of discomfort and pain. Instructions to imagine the painful stimulus produced similar physiologic effects in the "hypnotized" group and in the "awake" group: both groups showed physiologic responses (significantly increased heart rate and frontalis muscle tension and a tendency toward reduction in skin resistance) dissimilar to the responses of the group given the innocuous stimulus and similar to the responses of the group actually given the painful stimulus.