The effects of contextual information and gender on the prediction of hypnotic susceptibility

Council, Kirsch, and Hafner (1986) obtained empirical support for the hypothesis that significant correlations between questionnaire measures of absorption and hypnotic susceptibility are an artifact of subjects' beliefs about their own hypnotizability. We tested this hypothesis in a two-session experiment. During Session 1, subjects completed questionnaire measures of absorption, mystical experience, daydreaming frequency, and paranormal beliefs. During Session 2, subjects were tested for hypnotic susceptibility. Subjects were also exposed to one of three information manipulations: They were told about hypnotic testing either before or after filling out the questionnaires or were not told about hypnotic testing. The information manipulation moderated the prediction of susceptibility by the questionnaire measures for women, but not for men. For women, scores on the absorption questionnaire predicted susceptibility only when subjects were informed about hypnotic testing. In the told-after condition, this effect generalized to all of the remaining questionnaire measures. For men, none of the questionnaires was a reliable predictor of susceptibility.     

Hypnotic susceptibility in patients with conversion disorder

Conversion disorder has been associated with hypnotic susceptibility for over a century and is currently still believed to be a form of autohypnosis. There is, however, little empirical evidence for the relation between hypnotic susceptibility and conversion symptoms. The authors compared 50 patients with conversion disorder with 50 matched control patients with an affective disorder on measures of hypnotic susceptibility, cognitive dissociation, and somatoform dissociation. Conversion patients were significantly more responsive to hypnotic suggestions than control patients. In addition, conversion patients showed a significant correlation between hypnotic susceptibility and the number of conversion complaints. These results provide the first evidence of a relationship between hypnotic susceptibility and the presence and number of conversion symptoms.     

Hypnotic susceptibility and familial handedness

The possible relationship between hypnotic susceptibility and familiar handedness was examined. In a mass-testing session of students enrolled in introductory psychology classes, subjects were administered the Harvard Group Scale of Hypnotic Susceptibility, Form A and were also required to complete a questionnaire that ascertained information on their dominant handedness and that of their immediate family relatives. Subjects who had immediate sinistral relatives scored significantly lower in hypnotic susceptibility compared to those who had a history of familial dextrality. When immediate relatives of the original subject pool were tested on hypnotic susceptibility level, sinistral relatives scored lower in susceptibility than dextral relatives. This may indicate the existence of a familial component in hypnotic susceptibility.     

Furnishing hypnotic instructions with implementation intentions enhances hypnotic responsiveness

Forming implementation intentions has been consistently shown to be a powerful self-regulatory strategy. As the self-regulation of thoughts is important for the experience of involuntariness in the hypnotic context, investigating the effectiveness of implementation intentions on the suppression of thoughts was the focus of the present study. Participants were randomly assigned to one of four conditions (hypnotic instruction plus implementation intention, hypnotic instruction, implementation intention, and control condition). Results showed that participants who received information included in the "Carleton Skill Training Program" and in addition formed implementation intentions improved their hypnotic responsiveness as compared to all of the other three groups on measures of objective responding and involuntary responding. Thus, in line with the nonstate or cognitive social-psychological view of hypnosis stating that an individual's hypnotic suggestibility is not dispositional but modifiable, our results suggest that hypnotic responsiveness can be heightened by furnishing hypnotic instructions with ad hoc implementation intentions.     

Hypnotic experience and the autism spectrum disorder. A phenomenological investigation

In recent decades, the focus in autism research progressively expanded. It presently offers extensive material on sensorimotor disturbances as well as on perceptive-cognitive preferences of people with autism. The present article proposes not only a critical interpretation of the common theoretical framework in autism research but also focuses on certain experiences common to some people with autism and which can be appropriately understood by phenomenology. What I will call “hypnotic experiences” in autism are moments in which some individuals withdraw into intense sensorial and perceptive experiences. Following their examples, I use the term “hypnosis” primarily to describe a trance state in which the individuals become highly alert to and awake for an experience of a totally new kind. Through a close analysis of autobiographical writings from people with autism I defend the idea that the particularity of hypnotic experiences in autism consists in a certain qualitative shift within experience itself: what changes, in the hypnotic moments, is the way a person with autism relates to his/her own bodily experiences. If this qualitative shift is indeed difficult to account for within a reifying and intellectualist research perspective, phenomenology offers a large conceptual framework for understanding it. Phenomenology, and precisely, phenomenological psychopathology, will thus emerge as a major device in accounting for such “hypnotic experiences”. The argument mainly draws on the twofold structure of experience which is traditionally used in phenomenological research: it claims that in hypnotic experience people with autism are inclined to focus on non-reified “sensings”, “perceivings” and “movings”, and thus leave aside the object itself and any intentional reification of it. Finally, I will claim that this restriction to mere non-reified sensings might lead to a completely new conception of self and world. In the hypnotic experiences of autism, neither the subject nor the object come to a full-blown and independent existence. A thorough phenomenological analysis of hypnotic experience in autism therefore also has to face the question of a corresponding ontology of these experiences.     

Complexity and measurement of hypnotic susceptibility: a comment on Coe and Sarbin's alternative interpretation.

Coe and Sarbin's claim that a single role skill dimension accounts for individual differences in hypnotizability is not supported by an empirical analysis. We suggest that current measures of hypnotic susceptibility are not only factorially complex but contain a sizable nonhypnotic variance component. Implications for the assessment of "true" hypnotic susceptibility are discussed.     

Lack of correlation between hypnotic susceptibility and various components of attention

The purpose of our study was to measure the relationship between performance on various attentional tasks and hypnotic susceptibility. Healthy volunteers (N = 116) participated in a study, where they had to perform several tasks measuring various attention components in a waking state: sustained attention, selective or focused attention, divided attention and executive attention in task switching. Hypnotic susceptibility was measured in a separate setting by the Waterloo-Stanford Groups Scale of Hypnotic Susceptibility, Form C (WSGC).We found no significant correlation between any of the attentional measures and hypnotic susceptibility. Highly hypnotizables did not prove to be superior to or worse than the other individuals in any of the tests.These results do not support the neuropsychophysiological model of hypnosis, as they show no consistent relationship between hypnotic susceptibility and waking attentional performance.     

Hypnotic susceptibility and the perception of afterimages and dot stimuli

Three experiments were conducted to determine the relationship between hypnotic susceptibility level and the susceptibility to several perceptual phenomena. Experiment I required subjects to observe an induced afterimage in a light-proofed environment and to report the frequency of direction and color changes. In addition, subjects reported the persistence of the afterimage. Experiment II involved the observation of a black dot against a white background, with frequency of observed movement being the dependent measure. Experiment III was similar to the second experiment except that the stimulus was encompassed by a frame. In Experiments I and II, subjects judged high in hypnotic susceptibility reported perceiving the strongest effect. This phenomenon was virtually eliminated in the third experiment. These results were interpreted as supporting a process whereby subjects judged high in hypnotic susceptibility are better able to selectively attend to relevant cues in a stimulus array during conditions of perceptual impoverishment.     

Alcohol increases hypnotic susceptibility

One approach to hypnosis suggests that for hypnotic experience to occur frontal lobe activity must be attenuated. For example, cold control theory posits that a lack of awareness of intentions is responsible for the experience of involuntariness and/or the subjective reality of hypnotic suggestions. The mid-dorso-lateral prefrontal cortex and the ACC are candidate regions for such awareness. Alcohol impairs frontal lobe executive function. This study examined whether alcohol affects hypnotisability. We administered 0.8 mg/kg of alcohol or a placebo to 32 medium susceptible participants. They were subsequently hypnotised and given hypnotic suggestions. All participants believed they had received some alcohol. Participants in the alcohol condition were more susceptible to hypnotic suggestions than participants in the placebo condition. Impaired frontal lobe activity facilitates hypnotic responding, which supports theories postulating that attenuation of executive function facilitates hypnotic response, and contradicts theories postulating that hypnotic response involves enhanced inhibitory, attentional or other executive function.     

Hypnotic deafness: a psychophysical study of responses to tone intensity as modified by hypnosis.

Hypnotic deafness was suggested for 1000 Hz tones presented in random orders at seven intensities between 17 and 70 db. Subjects were 70 college students stratified into four levels of hypnotic susceptibility, ranging from low to high. Four conditions were presented within a single session. Two conditions tested normal hearing, one in waking and one in hypnosis; two tested reported loudness of the tones as reduced by hypnotic suggestion. The method of magnitude estimation was employed. Hearing reduction was found to correlate .59 with hypnotic susceptibility in the total sample. Few high hypnotizables reduced their hearing to zero; their mean residual hearing during the deafness conditions was 55% of normal. Power functions for the relationship between tone intensity and magnitude estimates for conditions of normal hearing and deafness were found to be relatively parallel and orderly, differing primarily in intercept value. Order effect anomalies are discussed. The "hidden observer" method showed that for 4 of the 70 subjects the covert hearing was found to be at least 20% greater than that reported overtly within hypnotic deafness and approached normal hearing. As in our previous hypnotic analgesia research, not all subjects who reduced their hearing significantly gave subsequent covert reports which differed from reported overt hearing. Discussion is given for evidence of two levels of information processing during hypnotically suggested perceptual distortions.     

Myths and misconceptions about hypnosis and suggestion: Separating fact and fiction

We present 21 prominent myths and misconceptions about hypnosis in order to promulgate accurate information and to highlight questions for future research. We argue that these myths and misconceptions have (a) fostered a skewed and stereotyped view of hypnosis among the lay public, (b) discouraged participant involvement in potentially helpful hypnotic interventions, and (c) impeded the exploration and application of hypnosis in scientific and practitioner communities. Myths reviewed span the view that hypnosis produces a trance or special state of consciousness and allied myths on topics related to hypnotic interventions; hypnotic responsiveness and the modification of hypnotic suggestibility; inducing hypnosis; and hypnosis and memory, awareness, and the experience of nonvolition. By demarcating myth from mystery and fact from fiction, and by highlighting what is known as well as what remains to be discovered, the science and practice of hypnosis can be advanced and grounded on a firmer empirical footing.     

Expert judgments of hypnosis from subjective state reports.

Suggestibility was assessed in 60 college students after a traditional hypnotic induction, an alert induction, progressive relaxation training, or instruction in goal-directed imagery. Responsiveness to suggestion did not differ between groups. Subjects also generated open-ended reports of their states of awareness and of their experience of 3 hypnotic suggestions. A sample of these reports from 24 moderately to highly suggestible subjects were evaluated by 18 experts in the field of hypnosis. Expert ratings of subjects' open-ended reports indicated that (a) traditional hypnotic inductions produce a state of consciousness that is indistinguishable from nonhypnotic relaxation training, (b) the subjective experience of hypnotic suggestions after imagination training is indistinguishable from that after hypnotic inductions, and (c) suggestibility is unrelated to state of consciousness as assessed by experts.     

The heat illusion test and its relevance to susceptibility to hypnosis

The Heat Illusion test is of interest because of the equivocal nature of the evidence concerning both what aspects of behaviour it measures and its power to predict hypnotic susceptibility. This test was administered to 99 subjects who were also tested for susceptibility to hypnosis. The power of the test to predict hypnotic susceptibility was found to be poor, when scoring was done in the classical manner, but, using the decrement of the threshold of perception, an alternative means of scoring was discovered which improved the predictive power of the test. The results are discussed in the light of this new aspect of the test.     

Hypnotic suggestion modulates cognitive conflict: the case of the flanker compatibility effect

The present work was aimed at investigating whether the flanker compatibility effect can be eliminated by means of a posthypnotic suggestion influencing attentional focusing. In Experiment 1, participants who scored high and low on hypnotic susceptibility performed the flanker compatibility task when naturally awake and when under a posthypnotic suggestion aimed at increasing the target's discriminability from the flankers. Results showed that the posthypnotic suggestion effectively eliminated the flanker compatibility effect in highly susceptible participants, whereas low-susceptibility participants did not show any reduction in the effect. In Experiment 2, highly susceptible participants performed the task after receiving a suggestion but without the induction of hypnosis. Results showed that the suggestion alone was not sufficient to reduce the flanker compatibility effect. These results support the view that in highly susceptible participants, hypnotic suggestion can influence the ability to focus on relevant information.     

Developmental Experiments in Hypnosis

Two-hundred-forty children, including ten boys and girls at each year level from five through sixteen, were selected from the entire public school population of a small city for testing on the Children's Hypnotic Susceptibility Scale. For most of these children, testing was repeated yearly for the next two years. Reliability for the Children's Scale was quite satisfactory for individual prediction. There were absolutely no differences in the hypnotic susceptibility of boys and girls in this sample. Intelligence had only low positive correlations with susceptibility. The correlation of age with susceptibility, measured either cross-sectionally or longitudinally, is positive and significant, but small. Changes in individual performance over time are generally minimal, and hypnotic susceptibility may be considered a relatively stable component of personality structure.     

Imagery vividness, hypnotic susceptibility, and the perception of fragmented stimuli

Two experiments were conducted to determine the role of hypnotic susceptibility level (high or low) and imaging ability (vivid or poor) in the performance of gestalt closure tasks. In Experiment 1, subjects were required to identify fragmented stimuli in the Closure Speed Test and in the Street Test. In Experiment 2, subjects reported on fragmented stimuli that were projected to the right eye and subsequently produced an afterimage. Individuals were asked to identify the composite if possible and to report on the duration of the afterimage. In both experiments, hypnotic susceptibility level and imaging ability affected reports of gestalt closure. The greatest number of correct closures was reported by those who were both high in hypnotic susceptibility and vivid in imaging ability. In addition, in the second experiment, this group also reported the longest enduring afterimage. These results are discussed in terms of the processes required to perform in a gestalt closure task.     

A social-cognitive skills approach to the successful modification of hypnotic susceptibility

Subjects low and medium in hypnotic susceptibility were administered cognitive strategy and instructional set information and also practiced responding to test suggestions in order to enhance susceptibility. Those in one modification treatment received this information both from the experimenter and by observing a videotaped female model who responded successfully to suggestions and reported on the cognitive strategies she used to do so. Those in a second modification treatment received the information and practice but were not exposed to the model. Low and medium susceptibles in a third condition (practice alone) received a hypnotic induction procedure and practice suggestions but neither modification information nor modeling. No-treatment controls performed a filler task. All subjects were posttested on two different susceptibility scales. Information plus modeling produced significantly greater increments on all objective and subjective indices of susceptibility on both posttests than did practice-alone or control treatments. Susceptibility increments in the information without model treatment always fell between those of the model and practice-alone treatments. In the modeling treatment, over half of the initial low susceptibles and over two thirds of the initial medium susceptibles scored as high susceptibles on both posttests. These findings provide strong support for a social-cognitive skill formulation of hypnotic susceptibility.     

Hypnosis and hemispheric asymmetry

Participants of low and high hypnotic susceptibility were tested on a temporal order judgement task, both with and without hypnosis. Judgements were made of the order of presentation of light flashes appearing in first one hemi-field then the other. There were differences in the inter-stimulus intervals required accurately to report the order, depending upon which hemi-field led. This asymmetry was most marked in hypnotically susceptible participants and reversed when they were hypnotised. This implies not only that brain activity changes in hypnosis, but also that there is a difference in brain function between people of low and high hypnotic susceptibility. The latter exhibited a faster-acting left hemisphere in the waking state, but faster right when hypnotised.     

Does 'hypnosis' by any other name smell as sweet? The efficacy of 'hypnotic' inductions depends on the label 'hypnosis'

Hypnosis is associated with profound changes in conscious experience and is increasingly used as a cognitive tool to explore neuropsychological processes. Studies of this sort typically employ suggestions following a hypnotic induction to produce changes in perceptual experience and motor control. It is not clear, however, to what extent the induction procedure serves to facilitate suggested phenomena. This study investigated the effect on suggestibility of (a) a hypnotic induction and (b) labelling that procedure 'hypnosis.' Suggestibility of participants was tested before and after an adapted hypnotic procedure, which was either labelled as 'hypnosis' or as 'relaxation.' The hypnotic procedure produced a modest increase in suggestibility when it was called 'relaxation,' but a very significant increase if it was labelled 'hypnosis.' The results are important for both clinical and experimental applications and indicate that labelling an induction procedure 'hypnosis' is an important determinant of subsequent responses to suggestion.