The role of compliance in hypnotic and nonhypnotic analgesia

We modified the standard procedure for administering finger pressure pain in order to assess the extent to which subjects biased their reports of pain reduction when exposed to compliance-inducing instructions. Experiment 1 used only highly hypnotizable subjects and found that compliance-induced reductions in reported pain were about half as large as the reported reductions produced by hypnotic analgesia suggestions. Experiment 2 used low as well as high hypnotizables and administered hypnotic or nonhypnotic analgesia instructions and compliance instructions to the same subjects on separate pain trials. Reported pain reductions produced by hypnotic and nonhypnotic analgesia suggestions and those produced by compliance instructions were substantially and significantly correlated. Furthermore, hypnotizability correlated with compliance-induced reported pain reductions as highly as it correlated with the reported reductions produced by hypnotic analgesia suggestions. Among high hypnotizables (but not low hypnotizables) compliant responding was predicted by social desirability. The findings of both studies indicate that compliance strongly influences the reports of hypnotic and nonhypnotic analgesia proffered by high hypnotizables. The role of compliance in the pain reductions reported by low hypnotizables is less clear-cut.     

Effects of instructional set on attributions of nonvolition during hypnotic and nonhypnotic analgesia

Fifty highly hypnotizable subjects were assigned to four treatment groups or a no-treatment control group and then underwent two pain stimulation trials. Half the treated subjects were administered hypnotic analgesia, half waking analgesia. Within hypnotic and nonhypnotic treatments, half the subjects were given actively worded analgesia instructions, half passively worded instructions. Subjects in the four treated groups reported equivalent pain reduction and equivalent use of coping imagery, although hypnotic subjects rated themselves as more deeply hypnotized than did nonhypnotic subjects. Both hypnotic and nonhypnotic subjects given passive instructions rated their pain reduction as occurring involuntarily, whereas those given active instructions reported that their pain was reduced through their active use of coping strategies. These findings support sociocognitive formulations of hypnotic responding that view ratings of involuntariness as reflecting contextually guided interpretations of behavior.     

Effects of active alert and relaxation hypnotic inductions on cold pressor pain

We contrasted relaxation and active alert hypnotic inductions with or without a specific suggestion for cold pressor pain analgesia. Groups of high (n = 38) and low (n = 27) hypnotizable subjects were tested; hypnotizability had been determined from results of the Stanford Hypnotic Susceptibility Scale, Form C. Cold pressor pain data were obtained after counterbalanced exposure to relaxation and active alert inductions. Highly hypnotizable subjects demonstrated lower pain scores than did low hypnotizable ones. Pain reports did not differ between induction conditions. Highly hypnotizable subjects given an analgesic suggestion showed lower pain scores than did those exposed only to hypnosis. The findings, conceptualized within E.R. Hilgard's (1977a) neodissociation theory, show that relaxation is not necessary for hypnotic analgesia.     

Eidetic-like imagery in hypnosis: rare but there

The production of eidetic-like imagery during hypnosis in subjects with high but not low hypnotizability was supported in three separate experiments using nonfakable stereograms (Julesz, 1971; Gummerman, Gray, & Wilson, 1972). In Experiment 1, 6 (25%) of 24 stringently chosen, high hypnotizables were able to perceive one of the superimposed stereograms (presented monocularly) during conditions of standard hypnosis or hypnotic age regression, or under both conditions, but not during waking. In Experiments 2 and 3, low and high hypnotizables were presented stereograms in an alternating, monocular fashion (one-half to each eye). In Experiment 2, 10% of the high hypnotizables perceived one or more stereograms in hypnosis or age regression, but not during waking. In Experiment 3, none of the 17 low hypnotizables reported correct stereograms, but 6 of the 23 high hypnotizables (26%) did. Relationships between imagery performance and visuo-spatial abilities were investigated. Results support the general hypothesis that hypnosis enhances imaginal processing of information to be remembered that is a literal or untransformed representation.     

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.     

Hypnotic susceptibility, baseline attentional functioning, and the Stroop task

According to the theoretical framework relating hypnosis to attention, baseline attentional functioning in highly hypnotizable individuals should be more efficient than in low hypnotizable individuals. However, previous studies did not find differences in Stroop-like tasks in which the measure indicative of the Stroop interference effect was based on response latencies. This study was designed to determine whether subjects with different levels of hypnotic susceptibility show differences in baseline attentional functioning. To assess this hypothesis, high, medium, and low hypnotizable subjects performed a Stroop task designed to evaluate accuracy performance, before being subjected to hypnotic induction. Results showed that the Stroop interference effect was smaller in high hypnotizable subjects than in low hypnotizable subjects, whereas it was not different between high, and medium hypnotizable subjects. This outcome supports the notion that baseline attentional functioning is related to hypnotic susceptibility.     

The role of expectation and memory‐retrieval techniques in the construction of beliefs about past events

This study assessed social factors affecting the elicitation of false reports for events occurring the day after birth. High, medium and low hypnotizable participants (N=170) were randomly assigned to hypnotic, guided imagery (non‐hypnotic), expectancy or control conditions. Participants were led to believe that they had experienced a specific event on the day after birth. Hypnotic and guided imagery participants were age regressed, while participants in the expectancy condition were provided with cues suggesting access to this memory was feasible. Relative to controls, these participants recalled higher levels of day‐after‐birth reports, although age‐regressed participants reported significantly more event specific details than expectancy participants. Furthermore, high and medium hypnotizables were more likely than low hypnotizables to recall events occurring the day after birth. Implications of this study within the therapeutic setting are discussed. Copyright © 2000 John Wiley & Sons, Ltd.     

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.     

Seeing is believing: the reality of hypnotic hallucinations

Two experiments investigated the reality attributed to hypnotic suggestion through subtle projection of a visual image during simultaneous suggestion for a visual hallucination that resembled the projected image. In Experiment 1, high and low hypnotizable participants were administered either a hypnotic induction or wake instructions, given a suggestion to hallucinate a shape, and then the projected image was subsequently introduced. Although highs in both conditions rated the projected image more vividly than lows, highs in the hypnosis (but not wake) condition made comparable reality ratings when the projected image was absent and present. In Experiment 2, high hypnotizable participants were administered a suggestion to see a shape on a wall. For half the participants the suggested image was projected on the wall and then removed, and for half the projection was initially absent and then introduced. Participants who had the projection absent and then present reported comparable reality and vividness ratings when the projection was absent and present. These findings indicate that elevated hypnotizability and hypnosis are associated with attributions of external reality to suggested experiences.     

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.     

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.     

Hypnosis, reporting bias, and suggested negative hallucinations.

We examined the role of reporting bias in hypnotic negative hallucinations by using a paradigm in which reporting bias was assessed independently of perceptual change. In Experiment 1, highly hypnotizable subjects reported significant loudness reductions when tested for hypnotic deafness. Later, however, these subjects biased their reported loudness reductions in the absence of perceptual change, and their reporting bias scores were almost as large as their hypnotic deafness reports. Subjects also biased their ratings of strategy use. In Experiment 2, ratings of blindness given in response to a hypnotic negative visual hallucination suggestion were significantly correlated with reporting bias scores obtained in this paradigm. Although hypnotic blindness and hypnotic deafness correlated significantly, the partial correlation between these variables was nonsignificant when reporting bias scores were statistically controlled. Theoretical implications are discussed.     

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 blindness: a behavioral and experiential analysis

This research examined the influence of visual information on a decision task that subjects were administered during hypnotically suggested blindness. Real, hypnotizable subjects and simulating, unhypnotizable subjects were tested in two experiments. Experiment 1 focused on behavioral responses, and Experiment 2 focused on experiential reactions. In both experiments, the findings indicated that the behavioral responses of reals were influenced by visual information despite their reported blindness. The behavioral responses of reals and simulators were essentially similar. The experiential data in Experiment 2 provided information about the phenomenal nature of subjects' reported blindness. The experimental reactions of reals and simulators were essentially different. The research is discussed in terms of the issues that need to be considered in the development of a model of hypnotic blindness.     

Distignuishing the source of memories reported during prior waking and hypnotic recall attempts

Subjects attempted to identify the occasion on which they first reported particular responses to questions that were asked twice during an experiment on hyphosis and memory 1 week earlier. During this earlier experiment, subjects of high and low hypnotizability had been randomly allocatd to one of two recall test sequences: wake-hypnosis ro wake-wake. Recall improved from the first (R1) to the second test (R2) in a comparable manner for both test sequences, indicating a failure of hypnosis to enhance memory. It is noteworthy that, when later queried about the origins of specific recollections, the majority of subjects exhibited a bias to attribute their responses to R1, regardless of whether hypnosis was used during R2. Moreover, low hypnotizables exposed to the hypnotic procedure and, to a lesser extent, high hypnotizables who recalled both times in the waking condition displayed and exaggerated tendency to overattribute recollections to R1. These data indicate that individuals cannot distinguish between memories retrieved prior to hypnosis and those that occured during hypnosis. Implications for implementing judicial standards regarding hypnosis are discussed.     

Moderating influences of hypnotic susceptibility on signal-detection task performance

This study investigated the differential influence of hypnotic susceptibility level on signal detection task (SDT) performance in waking and hypnotic conditions. As assessed by the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS: A) and the Stanford Hypnotic Susceptibility Scale, Form C (SHSS: C), 20 high (9–12), 20 medium (4–8), and 20 low (0–3) hypnotizables participated. In counterbalanced conditions of waking and hypnosis, Ss (Subjects) were given 36 signal detection trials, consisting of 12 strong signals, 12 weak signals, and 12 “no” signals. No differences were observed in the waking condition between low, medium, and high hypnotizables on strong and weak signal trials. In hypnosis, high hypnotizables exhibited significantly superior performance on the strong signal trials in comparison with low hypotizables, and performed significantly better on the weak signal trials than did the low and medium hypnotizables. Low and medium hypnotizables performed similarly in waking and hypnotic conditions, while high hypnotizables showed significant enhancements in performance for strong and weak signal trials during hypnosis. This research was supported, in part, by a grant from Fort Hays State University.     

Reflections on the varieties of hypnotizables: A commentary on Terhune and Cardeña

This commentary reflects on the varieties of high hypnotizable subjects suggested in the works by Barber, Barrett, Pekala and colleagues, and Terhune and Cardeña (2010). These different studies point to the existence of different types of low, medium, and high hypnotizable subjects. However, types of high hypnotizables have received the most attention. Two main concerns are raised in this commentary: (a) drawing parallels between the suggested typologies is not without problems given methodological differences among different studies, and (b) the low base rates of these special types is likely not to appeal to a typical clinician, already resistant to testing for hypnotizability, to conduct initial assessments so as to tailor suggestion to fit specific typologies.     

Moderating influences of hypnotic susceptibility on signal-detection task performance

This study investigated the differential influence of hypnotic susceptibility level on signal detection task (SDT) performance in waking and hypnotic conditions. As assessed by the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS: A) and the Stanford Hypnotic Susceptibility Scale, Form C (SHSS: C), 20 high (9–12), 20 medium (4–8), and 20 low (0–3) hypnotizables participated. In counterbalanced conditions of waking and hypnosis, Ss (Subjects) were given 36 signal detection trials, consisting of 12 strong signals, 12 weak signals, and 12 “no” signals. No differences were observed in the waking condition between low, medium, and high hypnotizables on strong and weak signal trials. In hypnosis, high hypnotizables exhibited significantly superior performance on the strong signal trials in comparison with low hypotizables, and performed significantly better on the weak signal trials than did the low and medium hypnotizables. Low and medium hypnotizables performed similarly in waking and hypnotic conditions, while high hypnotizables showed significant enhancements in performance for strong and weak signal trials during hypnosis. This research was supported, in part, by a grant from Fort Hays State University.     

Effects of preparatory information about sensations, threat of pain, and attention on cold pressor distress.

Pain experience is conceptualized as a combination of stimulus sensations (e.g., aching) and emotional distress. In Experiment 1, less distress was reported to cold pressor stimulation by subjects first told about stimulus sensations than by subjects who were uninformed or were told about symptoms of bodily arousal (e.g., tension). Adding a pain warning to sensation information blocked distress reduction, presumably by eliciting an emotional interpretation of the stimulus. In Experiment 2, subjects attending only to hand sensations reported less distress than subjects attending to their bodies. This decrease in the power of the stimulus to provoke emotion is presumably mediated by a schema of hand sensations formed by attention. In Experiment 3, subjects attending to hand sensations early in the immersion and distracting themselves later reported the same low levels of distress as did subjects who attended to hand sensations throughout. Subjects distracted throughout and subjects attending to hand sensations later showed no distress reduction. Therefore, stimulus schematization must precede distress reduction. Implications for distress control are discussed.     

Analgesic effects of posthypnotic suggestions and virtual reality distraction on thermal pain

The individual and combined effects of posthypnotic suggestion (PHS) and virtual reality distraction (VRD) on experimentally induced thermal pain were examined using a 2 x 2, between-groups design. After receiving baseline thermal pain, each participant received hypnosis or no hypnosis, followed by VRD or no VRD during another pain stimulus. Consistent with the hypothesis that hypnosis and VRD work via different mechanisms, results show that posthypnotic analgesia was moderated by hypnotizability but VRD analgesia was not. The impact of PHSs for analgesia was specific to high hypnotizables, whereas VRD was effective independent of hypnotizability. Results also show a nonsignificant but predicted pattern for high hypnotizables: Audio hypnosis combined with VRD reduced worst pain 22% more and pain unpleasantness 25% more than did VRD alone. Theoretical and clinical implications are discussed.