The International Journal of Clinical and Experimental Hypnosis
Volume 47, Number 1 - January 1999 - English
Cortical Event Related Potentials Show the Structure of Hypnotic Suggestions Is Crucial
Arreed Barabasz, Marianne Barabasz, Stacia Jensen, Steven Calvin, Michael Trevisan and Dennis Warner
Abstract: Electroencephalographic cortical event related potentials (ERPs) are affected by information processing strategies and are particularly appropriate for the examination of hypnotic alterations in perception. The effects of positive obstructive and negative obliterating instructions on visual and auditory P300 ERPs were tested. Twenty participants, stringently selected for hypnotizability, were requested to perform identical tasks during waking and alert hypnotic conditions. High hypnotizables showed greater ERP amplitudes while experiencing negative hallucinations and lower ERP amplitudes while experiencing positive obstructive hallucinations in contrast to low hypnotizables and their own waking imagination only conditions. The data show that when participants are carefully selected for hypnotizability and responses are time locked to events rather robust physiological markers of hypnosis emerge which reflect alterations in consciousness which correspond to participants' subjective experiences of perceptual alteration. Accounting for suggestion type reveals remarkable consistency of findings among dozens of researchers.
Measuring Change in the Subjective Experience of Hypnosis
Kevin M. McConkey, Vanessa Wende, and Amanda J. Barnier
Abstract: We indexed the subjective experience of hypnosis through the use of a continuous behavioral measure of the strength of the participant's experience at the time of the suggestion. Specifically, subjects turned a dial to indicate changes in their experience of the suggested effect during that experience. We asked 33 high, 47 medium, and 28 low hypnotizable subjects to use the dial during the suggestion, test, and cancellation phases of three hypnotic items: arm levitation, arm rigidity, and anosmia. The pattern of ratings differed according to the nature of the suggestion. Also, across the items, subjects who passed according to behavioral criteria experienced the suggested effect to a greater degree than those who failed did. Notably, whereas the ratings of highs and mediums did not differ for any item, they differed from lows on all three items. We discuss the implications of these findings in terms of the potential for this method to provide insight into the experience of hypnosis.
Expectancy and Suggestibility: Are the Effects of Environmental Enhancement Due to Detection?
Irving Kirsch, Cynthia Wickless, and Kathie H. Moffitt
Abstract: This study replicated the effect of Wickless and Kirsch's (1989) experiential expectancy manipulation, in which hidden lights and music from hidden sources were used to convince participants that they were responding successfully to suggestions for visual and auditory hallucinations. The hypothesis that the effect is mediated by detection of the manipulation was tested by providing some participants with cues that their experiences were due to actual changes in the physical environment, rather than their responses to suggestion. This hypothesis was not confirmed. A significant effect on suggestibility was obtained only among participants not given cues aimed at enabling detection of the manipulation, and among those provided with the cues, suspicion of the manipulation was negatively correlated with response to suggestion.
Posthypnotic Amnesia for Material Learned Before Hypnosis
Richard A. Bryant, Amanda J. Barnier, David Mallard, and Rachel Tibbits
Abstract: The impact of a suggestion for posthypnotic amnesia on material learned either before or during hypnosis was investigated across two experiments. In Experiment 1, very high, high, and low hypnotizable participants learned a word list either before or immediately after an hypnotic induction. During hypnosis, participants were given a suggestion for posthypnotic amnesia for the word list. After hypnosis, they were tested on recall, word-fragment, and word-recognition tasks. Experiment 2 replicated and extended Experiment 1 through application of the real-simulating paradigm. Across the two experiments, there was no difference in the performance of participants who learned the word list either before or during hypnosis. Although amnesia on direct memory measures was associated with high hypnotizability (Experiment 1), an explanation based on demand characteristics could not be excluded (Experiment 2). The implications of these findings for the use of posthypnotic amnesia as a laboratory analogue of disorders of autobiographical memory are discussed.
Intentional and Spontaneous Imagery in Hypnosis: The Phenomenology of Hypnotic Responding
Gail Comey and Irving Kirsch
Abstract: Students were given one of two versions of the Carleton University Responsiveness to Suggestion Scale (CURSS): a) the original version, which contains instructions to intentionally imagine goal-directed fantasies, and b) a modified version, in which instructions for suggestion-related imagery was deleted. Participants were asked to report their goal-directed fantasies and to indicate whether these occurred spontaneously or were generated intentionally. They were also asked whether they had tried intentionally to generate the suggested experience and to indicate whether they had believed that the suggested states of affairs were real (e.g., whether they thought a hallucinated cat really existed). The deletion of instructions for goal-related imagery significantly increased responsiveness to CURSS suggestions. Spontaneous goal-directed imagery was significantly correlated with behavioral response, but intentional imagery was not. Most successful responders tried to generate suggested experiences intentionally, indicated that they could have resisted challenge suggestions if they really wanted to, and reported believing in the reality of suggested ideomotor and challenge experiences, but not of cognitive suggestions. Voluntary attempts to generate suggested experiences were correlated with subjective responding.