Hypnotic susceptibility, interference, and alternation frequency to the Necker cube illusion

Two experiments (N = 60) were conducted to determine the effects of hypnotic susceptibility and interference on frequency of Necker cube apparent reversals (ARs). Interference was induced in Experiment 1 by having subjects respond to orally administered double-digit arithmetic (addition) problems while observing the Necker cube. In Experiment 2, counting backward by 3s served as interference. In both experiments, interference reduced ARs. Hypnotic susceptibility level also influenced ARs, with those scoring high on this attribute reporting more ARs than those scoring low. Attentional factors may have played a major role in producing the reported results.     

Personality and differential susceptibility to hypnosis: further replication and sex differences.

Following the study of Gibson & Curran (1974), a further sample of 45 subjects were tested on the Eysenck Personality Inventory (EPI) and a slightly modified form of the Stanford Hypnotic Susceptibility Scale (SHSS) in precisely the same way. The results in this second sample were broadly the same as those obtained in the earlier study. Combining the two samples, it was found that the sex variable provided some interesting contrasts. The power of the lie scale of the EPI to predict hypnotic susceptibility observed earlier was found to be a significant effect only for males. While there was no significant difference between the sexes in terms of the means and S.D.S. of the extraversion (E) and neuroticism (N) scales, when the interaction of these scales was studied males and females differed significantly. The population from the two studies (n = 88) was analysed by means of polar coordinates in the manner suggested by Eysenck (1966) with regard to the E nad N scales. Esyenck's prediction as to hypnotic susceptibility was strikingly confirmed. These data are briefly discussed in terms of alternative approaches to hypnosis from the 'state' and the 'non-state' viewpoints.     

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.     

Cognitive flexibility in hypnosis: response to change communication from the hypnotist.

It was predicted that modification of response as it indexes cognitive flexibility in the hypnotic subject is related to susceptibility to hypnosis and the difficulty of the hypnotic task attempted. Experiment 1 isolated two distinct hypnotic tasks (easy and difficult); alternative forms of each item conveyed either clear or unclear structure concerning the response that was perceived as most appropriate. In Experiment 2, 101 subjects were administered hypnotic induction procedures and tested for modification of response on both items; for each subject, the hypnotist posed a conflict in communication by plausibly requesting an alteration in response from the behavior that the subject had chosen to indicate previously. Change data demonstrated that hypnotic subjects modified their behavior in hypnosis, but their cognitive flexibility was much more relevant to easy than to difficult tasks. Results highlight a further dimension of role enactment as well as the special role cognitive skills in play in our understanding of performance on hypnotic test items.     

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.     

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.     

Hypnotic susceptibility and its relationship to outcome in the behavioral treatment of asthma: some preliminary data

12 subjects from an experiment on relaxation therapy for asthma were given the Harvard Group Scale of Hypnotic Susceptibility, Form A. Full scale hypnotic susceptibility scores were positively correlated, at a borderline significance, with improvement in the methacholine challenge test, a measure of asthma severity. Performance on the amnesia item of the Harvard Group Scale was correlated with improvement in self-reported symptoms of asthma.     

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.     

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 enhancement of cognitive-behavioral interventions for pain: an analogue treatment study.

Recent meta-analyses have shown that adding hypnosis enhances the effectiveness of cognitive-behavioral psychotherapy. This hypnotic enhancement effect was evaluated in the analogue treatment of pain. Individuals scoring in the high (n = 135) and low (n = 150) ranges of hypnotic suggestibility were randomly assigned to 1 of 6 conditions: Stress Inoculation Training, the same treatment provided hypnotically, nonhypnotic analgesia suggestions, hypnotic analgesia suggestions, a hypnotic induction treatment, or a control condition. The 5 analogue treatments reduced experimental pain more than the control condition, but were not different from one another. Under circumstances optimized to detect an enhancement effect, neither Stress Inoculation Training nor analgesia suggestions produced more relief when delivered in a hypnotic context than identical treatments provided nonhypnotically.     

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.     

Latency and frequency reports to the Necker cube illusion: effects of hypnotic susceptibility and mental arithmetic

An experiment (N = 32) was conducted to assess latency of first apparent reversal (AR) and AR frequency while observing the Necker cube illusion. Subjects who were either high in hypnotic susceptibility (susceptibles) or low in hypnotic susceptibility (resistant subjects) observed the cube either while performing or not performing mental addition problems. Susceptibles reported perceiving the first AR more quickly and a greater frequency of ARs than did resistant subjects. Also, latency of the first AR was negatively correlated with AR frequency. These results were interpreted in terms of the ability of susceptibles to allocate concentrative or selective attention in a manner that was conducive to faster performance, when faced with competing tasks.     

Individual differences in afterimage persistence: relationships to hypnotic susceptibility and visuospatial skills.

To investigate the moderating role of individual differences in hypnotic susceptibility and visuospatial skills on afterimage persistence, we presented a codable (cross) flash of light to 40 men and 46 women who had been dark adapted for 20 min. In an unrelated classroom setting, subjects had previously been given two standardized scales of hypnotic susceptibility (Harvard Group Scale of Hypnotic Susceptibility, Shor & Orne, 1962; Group Stanford Hypnotic Susceptibility Scale, Form C, Crawford & Allen, 1982) and the Mental Rotations Test (Vandenberg & Kuse, 1978). The first afterimage interval and the afterimage duration correlated significantly with hypnotic responsiveness, supporting Wallace (1979), but did not show the anticipated relationships with mental rotation visuospatial skills. Individuals in the high hypnotizable group had (a) significantly longer afterimage intervals between its first appearance and first disappearance than did those in medium or low groups, as well as (b) significantly longer afterimages between the first appearance and the final disappearance than did those in low groups, but those in medium groups did not differ significantly from the other groups. Discriminant analysis using the afterimage persistence measures classified correctly 65.2% of high hypnotizables, 37.5% of medium hypnotizables, and 54.8% of low hypnotizables. Hypothesized cognitive skills that assist in the maintenance of afterimages and underlie hypnotic susceptibility include abilities to maintain focused attention and resist distractions over time and to maintain vivid visual images.     

关于场依存性－独立性与催眠感受性及性格的比较研究

对场依存性独立性认知方式与催眠感受性及Ｙ—Ｇ性格测验所评定的人格特征的相互关系进行了研究,结果表明：场依存性－独立性与催眠感受性之间不存在相关关系,提示两者为彼此独立的人格特征;在人格特质方面．场依存性者比场独立性者具有更强的社会外向性、社交活动主导性和乐天性;而场独立性者则具有较强的神经质倾向;在人格类型上,场依存性者和场独立性者均普遍表现为Ａ、Ａ’和Ｄ型,而Ｃ型则更可能是场独立性者所具有的特征;从人格类型的研究角度证明,内、外向性格与场依存性－独立性基本上分属两个不同的人格维度;场依存性－独立性与个体心理健康水平无关。     

Personality types and hetero- versus auto-hypnosis

The Multivariate Personality Inventory (MPI; Magaro & Smith, 1981), the Harvard Group Scale of Hypnotic Susceptibility (HGSHS; Shor & Orne, 1962), and the Inventory of Self-Hypnosis (ISH; Shor, 1970) were used to investigate the relationship between personality style and hypnotic procedure in the determination of hypnotic susceptibility. On the basis of MPI scores, a normal college population was segregated into 5 personality styles: hysteric, manic, depressive, character disorder, and compulsive. The hysteric personality was found significantly more hypnotizable than the other personality types in the HGSHS induction context, whereas the compulsive personality was found significantly more hypnotizable in the ISH induction context. Results are discussed in terms of personality and situational factors in relation to previous hypnotic susceptibility research.     

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.     

Expectancy versus absorption in the prediction of hypnotic responding

The Absorption Scale, a measure of imaginative involvement, was administered to 64 subjects in the context of a hypnosis experiment and to an additional 64 subjects in a context unrelated to hypnosis. Expectancies of responding to hypnotic suggestions were assessed both before trance induction and after trance induction but before administration of hypnotic test suggestions. Hypnotic depth was assessed on the Long Stanford Scale (LSS) before the administration of test suggestions, and on the Inventory of Hypnotic Depth (IHD) after the hypnosis session. Absorption was correlated with hypnotic responsivity and expectancy, but only when assesed in the hypnotic context. Completing the Absorption Scale in a hypnotic context appeared to affect hypnotic responsiveness by altering subjects' expectancies. Only postinduction expectancies were uniquely predictive of response to hypnotic test suggestions, and all variables except the LSS were predictive of IHD scores. Results of path analysis supported the hypothesis that trance inductions alter expectancies for responding to hypnotic suggestions and that these altered expectancies determine subsequent hypnotic behavior.     

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.