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 experiential 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotically induced emotional numbing: A real-simulating analysis.

This study compared 20 real, hypnotized and 20 simulating, unhypnotized participants who were administered a hypnotic induction and then presented with emotionally distressing and neutral visual images. Half were administered a hypnotic suggestion for emotional numbing. Reals and simulators who received the emotional numbing suggestion reported comparably less responsivity to distressing stimuli than others. Whereas emotionally numb reals displayed little change in electromyographic (EMG) activity during the distressing stimuli, simulators displayed marked reduction in EMG activity. Reals (not simulators) displayed a dissociation between their affective response and awareness of the negative content of the stimuli following the numbing suggestion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trance logic duality and hidden observer responding in hypnotic, imagination control, and simulating subjects: A social psychological analysis.

Tested the hypothesis that a tolerance for logical incongruity characterizes hypnotic responding and is related to reports of duality experiences during age regression and hidden-observer responding during suggested analgesia. 30 undergraduates (the "reals") with high scores on a responsiveness-to-suggestion scale were randomly assigned to hypnotic or imagination control treatments, while 15 undergraduates with low scores were assigned to a simulation treatment in which they were instructed to fake hypnosis. Ss were assessed on 6 indicators of logical incongruity, given age-regression suggestions and perception tasks, administered a suggestion for analgesia and hidden observer instructions, and interviewed. Results do not support the hypothesis. The differences in responding that did emerge between reals and simulators were accounted for by the different task demands to which Ss were exposed. These behavioral differences, which have been previously interpreted in terms of intrinsic characteristics of hypnosis, may instead reflect a combination of between-treatments differences in demands and between-Ss differences in the interpretation of those demands and in the ability to fulfill them. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trance logic, susceptibility screening, and the transparency response.

Two groups of hypnotizable ("real") Ss were screened on the Harvard Group Scale of Hypnotic Susceptibility and the individually administered Revised Stanford Profile Scales of Hypnotic Susceptibility or on the Group Scale alone. These 26 Ss were compared with 15 simulating Ss (who were group and individually screened) on 5 measures of trance logic (TL). As predicted, the stringently screened Ss passed more of the criterion hallucinations used in the tests of TL than group-screened-alone Ss, whereas simulators passed all the criterion hallucinations. However, the 2 groups of reals were indistinguishable on measures of TL, and only the transparency response differentiated reals and simulators. In their guesses of group assignment, hypnotists were better able to differentiate less stringently screened than stringently screened reals from simulators. Although experimenter blindness may be compromised by the use of less stringently screened Ss in TL research, bias was not associated with differential responding on TL tasks. The finding that reals who reported transparency also reported weakened or imperfect hallucinations supports the hypothesis that less than compelling hypnotic experience, not contralogical responding, is at the heart of transparency reports. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotic blindness, awareness, and attribution.

Examined whether performance on a spelling task would be influenced by visual information in the reported absence of hypnotized subjects' awareness of that information. Experiment 1 visually presented uncommon spellings of homophones to subjects before and during a suggestion for hypnotic blindness, and subsequently tested subjects' spelling of the homophones. Words presented during hypnotic blindness influenced subjects' spelling performance. Subjects' attributions of their performance did not involve awareness of the homophones. Experiment 2 used the nonexperiment methodology to examine the impact of demand characteristics and indicated that the performance attributions of subjects of Experiment 1 could not be explained in these terms. The discussion focuses on implicit perception in hypnotic blindness and on the relevance of attributions about behavioral performance on hypnotic phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotically induced limb anesthesia and adaptation to displacing prisms: A failure to confirm.

Tested 3 groups of 10 undergraduates for accuracy of pointing at a visual target before and after wearing displacing prisms. One group consisted of highly susceptible Ss given a hypnotic suggestion for limb anesthesia following the pretest, and a 2nd group included low susceptible Ss instructed to fake limb anesthesia. A control group unselected on susceptibility received no special instructions. The high susceptibles reported significantly greater felt anesthesia than Ss in the other 2 treatments. Nevertheless, Ss in all 3 groups showed very large displacement errors (i.e., errors in pointing) following prism removal. Results fail to confirm reports that placement errors were eliminated by hypnotic suggestion in highly susceptible Ss. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnosis, reporting bias, and suggested negative hallucinations.

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 Exp 1, highly hypnotizable Ss reported significant loudness reductions when tested for hypnotic deafness. Later, however, these Ss 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. Ss also biased their ratings of strategy use. In Exp 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnosis, suggestion, and placebo in the reduction of experimental pain.

Two experiments compared placebo and hypnotic analgesia in high and low hypnotizable subjects. Experiment 1 demonstrated that hypnotic and placebo analgesia were equally ineffective in low hypnotizables, but that hypnotic analgesia was much more effective than placebo analgesia in high hypnotizables. Experiment 2 replicated these results, but also included low and high hypnotizables who were given a nonhypnotic suggestion for analgesia. Both the low and high hypnotizables in this group reported greater suggested than placebo analgesia and as much suggested analgesia as high hypnotizable hypnotic subjects. Both experiments found substantial discrepancies between the amount of pain reduction subjects expected from the various treatments and the amount of pain reduction they actually reported following exposure to those treatments. In Experiment 2, subjects in all treatments who reduced reported pain engaged in more cognitive coping and less catastrophizing than those who did not reduce pain. Theoretical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suggested ("hypnotic") visual hallucinations: Experimental and phenomenological data.

Tested 74 female student nurses' responses to a pretreatment hallucination suggestion to see an object that was not present. Each S was then exposed to either hypnotic induction procedure or task motivational instructions, and was again tested on response to an equivalent posttreatment hallucination suggestion. Next, each S was assessed on the Barber Suggestibility Scale (BSS) and on a self-rating of hypnotic depth measure. Finally, Ss were interviewed individually by a "blind" E to determine their phenomenological experiences during the posttreatment hallucination suggestion. There were significant positive correlations between scores on the posttreatment hallucination suggestion and scores on the BSS, self-ratings of hypnotic depth, and pretreatment hallucination suggestion. Similar phenomenological experiences were reported by Ss tested under the hypnotic induction and task motivational treatments, and by Ss who reported that they "saw" and those who reported that they "vividly imagined" the suggested object. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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 nonhypnotized 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotic deafness: Now you hear it—now you still hear it.

24 undergraduates who had been preselected as either high or low on hypnotic susceptibility (according to the Harvard Group Scale of Hypnotic Susceptibility) listened to 2 dichotically presented word pair lists. One list was presented following a suggestion for unilateral deafness and the other following instructions for selective attention. All Ss received both treatments in counterbalanced order, and an index of auditory intrusions from the unattended (or "deaf") ear was obtained following each trial. High susceptibles showed no more evidence of unilateral hearing impairment than low susceptibles under either the deafness suggestion or selective attention treatment. Nevertheless, high susceptibles reported greater deafness than low susceptibles on a posttest scale. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The reality of hypnotic analgesia: A comparison of highly hypnotizables with simulators.

Used the real–simulator design to investigate the reality of hypnotic analgesia when normally painful stress was induced by immersing a hand and forearm in circulating ice water (cold pressor response). 2 groups of Ss (12 14–22 yr old selected highly hypnotizable "reals" and 12 13–27 yr old insusceptible "simulators"), determined by the Harvard Group Scale of Hypnotic Susceptibility (Form A) and the Stanford Hypnotic Susceptibility Scale (Form C), participated in a single session during which suggestions for pain reduction were given in both the waking and hypnotic conditions. The simulators proved remarkably successful in predicting and imitating the responses of the reals, except for a tendency to overreact and exaggerate compliance with suggestions. The genuineness of hypnotic analgesia was attested, however, by the differences between the honesty reports of the reals and those of the simulators who attempted to behave as hypnotized Ss are expected to do. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotic age regression and the occurrence of transitional object relationships.

Object relations theory and subsequent empirical investigations have established the characteristic ways in which children aged 2–6 yrs utilize transitional objects (e.g., teddy bears or blankets). Three of these characteristics—spontaneity, specificity, and intensity—were used as the primary criteria to investigate the genuineness of hypnotic age regression when Ss were regressed to age 3 and placed in emotional situations typical of those reported clinically. Two groups of college students (16 highly susceptible, as "reals," and 15 low susceptible, as simulators; Ss were administered the Harvard Group Scale of Hypnotic Susceptibility and a version of the Stanford Profile Scales of Hypnotic Susceptibility) behaved differentially on all 3 measures, with reals behaving in a generally more childlike manner, thus suggesting an effect attributable to the hypnotic condition. Further, the behavior of these Ss was compared to that of 77 children aged 1–6 yrs; reals and children were statistically indistinguishable on the 2 criteria on which they were compared, but simulators differed significantly from both groups. This pattern of results, along with real–simulator differences, suggests a more complete reproduction of an earlier affective process as a function of meaningful hypnotic age regression. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of gender on susceptibility to multiple sclerosis and age of onset in concordant sibships

The tendency of highly hypnotizable participants to bias their retrospective perceptual reports in response to instructional demands was reexamined with the addition of low-hypnotizable control participants instructed to simulate hypnosis. Mean scores of high-hypnotizable participants and simulators did not differ, but the responses of simulators to the demand instruction was less variable than those of high-hypnotizable participants, and the shape of the response distribution was different. Unlike simulators, some high-hypnotizable participants who had reported changes in perception that were consistent with a hypnotic suggestion subsequently reported changes opposite to those suggested by a demand instruction. These data were interpreted as suggesting that the responses of high-hypnotizable participants to both the demand instruction and the preceding hypnotic suggestion were not entirely due to compliance.     

Reporting biases in hypnosis: Suggestion or compliance?

The tendency of highly hypnotizable participants to bias their retrospective perceptual reports in response to instructional demands was reexamined with the addition of low-hypnotizable control participants instructed to simulate hypnosis. Mean scores of high-hypnotizable participants and simulators did not differ, but the responses of simulators to the demand instruction was less variable than those of high-hypnotizable participants, and the shape of the response distribution was different. Unlike simulators, some high-hypnotizable participants who had reported changes in perception that were consistent with a hypnotic suggestion subsequently reported changes opposite to those suggested by a demand instruction. These data were interpreted as suggesting that the responses of high-hypnotizable participants to both the demand instruction and the preceding hypnotic suggestion were not entirely due to compliance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

OCMAP-PLUS: a program for the comprehensive analysis of occupational cohort data

Previous research indicated that high-hypnotizable participants reported more primary-process mentation in hypnotic dreams than low-hypnotizable participants instructed to simulate hypnosis. Differences in primary process were not evidenced in response to instructions for a "hidden part" of the participant to report on the hypnotic dream. This research replicated and extended these findings by showing that high-hypnotizable participants (n = 20) passing the dream suggestion reported more primary process in their dreams than high-hypnotizable participants instructed to remain alert and think and imagine along with suggestions (n = 20). Differences in primary process were not evidenced in response to hidden-observer suggestions, and the frequency of dream (87% hypnosis vs. 96% imagining) and hidden-observer responses (100% in both groups) was equivalent across hypnotic and nonhypnotic groups. The results provided qualified support for a psychoanalytic model of hypnosis: Differences in primary process were apparent in response to the dream but not the hidden-observer suggestion.     

Responsiveness to suggestions following waking and imagination instructions and following induction of hypnosis.

2 experiments are reported to test the increase of responsiveness to suggestion tests following hypnotic induction over responsiveness to such tests in waking and imagination conditions, an increase that has been doubted as a result of experiments by Barber and Calverley. In the 1st experiment 60 Ss were divided into groups of 20, each serving under 1 of 3 conditions in a 1st session (waking, imagination, hypnosis). All received a standard hypnotic induction in a 2nd session. While the treatment effects did not yield significant differences on the 1st day, there were significant gains in responsiveness to suggestions by the waking and imagination groups in the 2nd session. In the 2nd experiment, with some methodological improvements, 90 Ss served in 6 groups of 15 in: (1) imagination without expectation of hypnosis, (2) imagination with expectation of hypnosis, (3) hypnotic induction, and (4) various combinations. Significant gains were found with hypnotic induction throughout. State reports (subjective responses of drifting into hypnosis) showed that those Ss within both imagination and hypnotic induction conditions who reported themselves as becoming hypnotized yielded the highest suggestibility scores. There is difficulty in obtaining significant treatment effects unless Ss were as their own controls. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental designs, expectancy effects, and hypnotic analgesia.

40 undergraduates who scored high on the Harvard Group Scale of Hypnotic Susceptibility were randomly assigned to 1 of 4 groups. Each group received 3 60-sec immersions of cold-pressor pain stimulation. Immersions were associated with either hypnotic, waking, or no analgesia (control) instructions. The treatments and their order were varied across groups to induce different expectations about the efficacy of hypnotic and waking analgesia. Magnitude estimates and category scale ratings of pain indicated that hypnotic analgesia was more, less, or equally as effective as waking analgesia, depending on the expectations induced by varying treatment order. Pain ratings were also related to the type of cognitive activity (e.g., imaginative coping) engaged in during an immersion. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of suggestion and distraction on reported pain in subjects high and low on hypnotic susceptibility.

84 18–30 yr old undergraduates high or low in hypnotic susceptibility (the Carleton University Responsiveness to Suggestion Scale) immersed an arm in ice water on 2 separate trials. Within susceptibility levels, Ss were randomly assigned to 3 groups, with an equal number in each group. Between trials, Ss in 1 group were administered a suggestion to imagine their hand as numb and insensitive, those in a 2nd group practiced a distraction task to be used during the 2nd trial (shadowing words), and those in a 3rd group (controls) received no special instructions. The suggestion significantly lowered rated pain in high but not in low susceptibles. Contrary to dissociation accounts of hypnotic susceptibility and suggested analgesia, low-susceptible shadowers showed as much reduction in rated pain as high susceptibles given suggestion. The social psychology of the experimental pain assessment situation is discussed. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trance logic as incomplete responding.

Two experiments tested predictions derived from the logical incongruity and differential demands hypotheses of trance logic responding. In Exp I, Ss that were highly susceptible to hypnosis showed higher levels of responding on 3 trance logic indexes (i.e., transparent hallucinating, duality, incongruous writing in age regression) than did Ss low in susceptibility to hypnosis who were instructed to fake hypnosis (i.e., simulators). In line with the differential demands hypothesis, hypnotic "reals" were less likely than simulators to report believing in the reality of the suggested situations and were less likely to report fine details in their hallucinations. Rate of trance logic responding correlated negatively with the degree to which hypnotic reals rated themselves as subjectively experiencing suggested effects, and as becoming absorbed in suggestions. Exp II found that highly susceptible hypnotic and nonhypnotic Ss (collectively called "reals") responded equivalently on all suggestions. High- and low-susceptible simulators also performed equivalently on all suggestions. Consistent with the differential demands hypothesis, (a) trance logic indexes differentiated reals from simulators when these indexes also measured incomplete subjective responding, and (b) trance logic indexes that failed to measure incomplete responding also failed to differentiate reals from simulators. (PsycINFO Database Record (c) 2010 APA, all rights reserved)