He compared hypnotic attention with hypnotic obstruction (which was a suggestion that a brick wall was “covering” the L or R visual field). They found a difference between attended and ignored stimuli in the Frontal area ERP!
However, there are problems with ERPs and localization due to diffusion of signal throughout the scalp.
In a hypnotic obstruction condition the effect is a bit later than in selective inattention; and it is more posterior than in selective inattention. Thus, if we find a difference due to hypnotic obstruction at P100, it may be due to selective inattention. The difference we can produce with hypnotic obstruction comes at P200 and posterior in the occipital cortex, where a visual stimulus is processed. Generation of internal images may contribute. Are there differences if you tell yourself not to see vs to see something obstructing the image?
Ability to do the hypnotic obstruction is related to the eyeroll item on the Hypnotic Induction Profile (HIP). (High eyeroll score makes it easier to reduce P200 amplitude in response to the obstruction suggestion.) So eyeroll score on the HIP has some validation as a biological marker.
Effects of supportive group therapy for cancer patients study: anxiety and depression modulate the pain more than the location of the cancer. Melzack’s theory indicates input from cortex can modulate pain. We taught Self Hypnosis for pain control: used metaphors that induce relaxation, suggestions to filter hurt out of the pain, not fight the pain, focus on a competing sensation. By end of year the intervention group had half the pain that the non-intervention group had. The frequency and duration of pain attacks were not different.
We are now in year 5 of a 10 year replication study.

DePascalis, Vilfredo (1994). Event-related potentials during hypnotic hallucination. International Journal of Clinical and Experimental Hypnosis, 42 (1), 39-55.

Event-related potentials were elicited by visual stimulation and recorded at frontal, central, and posterior scalp sites so as to study the psychophysiological process associated with hypnotic hallucination. Subjects were screened using two measures of hypnotic susceptibility (Harvard Group Scale of Hypnotic Susceptibility, Form A and the Stanford Hypnotic Susceptibility Scale, Form C). Seven high and 9 low hypnotizable right-handed females participated in the experiment. Eight intermediate hypnotizable right-handed females served as controls. Peak amplitudes and latencies of P1, N1, P2, N2, and P3 components were compared in two hypnotic conditions (obtained by means of hypnotic suggestions): stimulus enhancement and stimulus elimination. High hypnotizable subjects displayed a significant attenuation of the P1 and N1 amplitudes of the evoked response while experiencing stimulus elimination. The effect for the P1 component was greatest at the posterior sites compared to that found at the anterior and central sites. A similar trend across condition was also observed for P3 peak amplitude, even though the Group x Condition interaction was only marginally significant (p <.07). during negative hallucination, P3 peak latency for high hypnotizables was shorter than that obtained during stimulus enhancement. This effect was more pronounced across the right hemisphere. These results are discussed in light of previous findings. 1992 Page, Roger A.; Handley, George W. (1992). Effects of 'deepening' techniques on hypnotic depth and responding. International Journal of Clinical and Experimental Hypnosis, 40, 157-168. The present study attempted to assess the effectiveness of commonly used deepening techniques and of surreptitiously provided stimulation on hypnotizability scores, in-hypnosis depth reports, retrospective realness ratings, and the Field Inventory of Hypnotic Depth (Field, 1965). High, medium, and low hypnotizables were assigned in equal numbers to 1 of 3 groups, each containing 54 Subjects. Controls were compared to Subjects receiving 2 deepening techniques or 2 suggestions for positive and negative hallucinations that were surreptitiously enhanced. Of the 4 dependent measures employed, the only significant different between groups related to a change in depth reports for the manipulation items themselves, leading to the conclusion that the effect of the techniques was at best minimal and transient. Some methodological and conceptual issues are also discussed. Spanos, Nicholas P.; Burgess, C. A.; Cross, P. A.; MacLeod, G. (1992). Hypnosis, reporting bias, and suggested negative hallucinations. Journal of Abnormal Psychology, 101, 192-199. 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. Results are used to support a skeptical view of hypnotic response as being based on compliance. 1991 Kunzendorf, Robert G.; Beltz, Susan McLaughlin; Tymowicz, Gina (1991-92). Self-awareness in autistic subjects and deeply hypnotized subjects: Dissociation of self-concept versus self-consciousness. Imagination, Cognition and Personality, 11, 129-141. By refining past tests of self-awareness in mirrors, current testing demonstrates that autistic subjects' percepts are dissociated from self-concept, whereas hypnotized subjects' sensations are dissociated from self-consciousness. In the current test of self-concept, subjects could not _directly_ see a line inside the box on their lap, but subjects could see the line _indirectly_ in a televised mirror image. When instructed to touch the line, autistic subjects reached towards the televised line, whereas nonautistic subjects reached towards the actual line occluded inside the box. This first result suggests that the autistic subject's visual percept of the televised line is dissociated from its spatial relationship to the subject's self-concept. In the current test of self-consciousness, subjects were told to use a televised mirror-image to move their hands together until touching, but were not told that they were actually seeing a pre-recorded tape of their hands struggling unsuccessfully to touch. When queried, hypnotized subjects denied that their tactually joined hands were touching, whereas nonhypnotized subjects confirmed that their hands were touching. This latter result suggests that the hypnotized subject's hand-touching sensations are dissociated from the immediate and incontrovertible self-consciousness _that one is perceiving the hands touching (not imaging them touching)_. 1990 Ross, Colin A.; Miller, S. D.; Reagor, P.; Bjornson, L.; Fraser, G. A.; Anderson, G. (1990). Schneiderian symptoms in multiple personality disorder and schizophrenia. Comprehensive Psychiatry, 31, 111-118. NOTES Schneiderian first-rank symptoms of schizophrenia were equally common among 102 patients with multiple personality disorder in all four centers where data was collected. The average multiple personality disorder (MPD) patient had experienced 6.4 Schneiderian symptoms. When these 102 cases are combined with two previously reported series of MPD cases, an average of 4.9 Schneiderian symptoms in 368 cases of MPD is noted. This compared with an average of 1.3 symptoms acknowledged by 1,739 schizophrenics in 10 published series. Schneiderian symptoms are more characteristic of MPD than of schizophrenia. 1989 Bryant, Richard A.; McConkey, Kevin M. (1989). Hypnotic blindness: A behavioral and experiential analysis. Journal of Abnormal Psychology, 98, 71-77. NOTES "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 Exper. 2 focused on experiential reactions. In both experiments, the findings indicated that the behavioral responses of reals were influenced by visual info. 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" (p. 71). Bryant, Richard A.; McConkey, Kevin M. (1989). Visual conversion disorder: A case analysis of the influence of visual information. Journal of Abnormal Psychology, 98, 326-329. NOTES "examined the influence of visual information on a decision task that was administered to an individual with monocular visual conversion disorder. Findings indicated that his performance was influenced by the visual information and by motivation instructions. The findings are discussed in terms of a model of hysterical blindness that recognizes the interplay of cognitive and motivational processes" (p. 326). Spanos, Nicholas P.; Lush, Nancy I.; Gwynn, Maxwell I. (1989). Cognitive skill-training enhancement of hypnotizability: Generalization effects and trance logic responding. Journal of Personality and Social Psychology, 56 (5), 795-804. Compared low-hypnotizable subjects who simulated hypnosis, underwent cognitive skill training, or served as no- treatment controls to subjects who scored as high hypnotizables without training (natural highs) on response to analgesia, age-regression, visual hallucination, selective amnesia, and posthypnotic suggestions. Subjects who attained high hypnotizability following skill training (created highs) did not differ from natural highs on any response index. Natural and created highs scored lower than simulators but higher than controls on the behavioral and subjective aspects of test suggestions. Simulators, however, were significantly less likely than natural highs or skill- trained subjects to exhibit duality responding or incongruous writing during age regression or transparent hallucinating. Results suggest that the hypnotic responses of natural and created highs are mediated by the same cognitive variables and that enhancements in hypnotizability produced by skill training cannot be adequately explained in terms of compliance. 1988 Lynn, Steven Jay; Rhue, Judith W. (1988). Fantasy proneness: Hypnosis, developmental antecedents, and psychopathology. American Psychologist, 43 (1), 35-44. This article presents a summary of the findings of our ongoing research program on the fantasy-prone person. In seven studies, nearly 6,000 college students were screened in order to obtain five samples of 156 fantasy-prone subjects. Fantasy- prone subjects (fantasizers) were selected from the upper 2%-4% of the college population on a measure of imaginative involvement and contrasted with nonfantasizers (lower 2%-4%), and medium fantasy-prone subjects (middle range). General support was secured for Wilson and Barber's construct of fantasy proneness: Fantasizers were found to differ from nonfantasizers, and in many cases also from medium-range subjects, on measures of hypnotizability, imagination, waking suggestibility, hallucinatory ability, creativity, psychopathology, and childhood experiences. Differences in hypnotizability were most reliable when subjects participated in a multisession study and were screened not only with the screening inventory, but also with an interview that substantiated their fantasy-prone status. However, our findings indicated that less correspondence between fantasy proneness and hypnotizability exists than Wilson and Barber suggested. Hypnotic responsiveness is possible even in the absence of well-developed imaginative abilities, and not all fantasizers were highly hypnotizable. Fantasizers recollected being physically abused and punished to a greater degree than other subjects did and reported experiencing greater loneliness and isolation as children. Many fantasizers appeared to be relatively well-adjusted; however, a subset of fantasizers were clearly maladjusted based on self- report, Minnesota Multiphasic Personality Inventory (MMPI), and Rorschach test data. Because of the diversity inherent in the fantasy-prone population, it is misleading to think of individuals at the extreme end of the fantasy-proneness continuum as conforming to a unitary personality type. Spiegel, David; Barabasz, Arreed F. (1988). Effects of hypnotic instructions on P300 event-related-potential amplitudes: Research and clinical applications. American Journal of Clinical Hypnosis, 31, 22-27. Apparently conflicting findings in two recent studies of the effects of hypnotic hallucination on the P300 component of cortical event-related potentials are examined. In one study, Barabasz and Lonsdale (1983) found an increase in P300 amplitude in response to hypnotic anosmia instructions. However, Spiegel, Cutcomb, Ren, and Pribram (1985) obtained a decrease in P300 amplitude after instructing high hypnotizables that an imaginary cardboard box blocked their view of the stimulus generator. These differences are reconciled on the basis of differences in the hypnotic instructions given. The former study employed language which emphasized negation ("You will not smell anything at all"), while the latter had subjects focus on a competing obstructive hallucination. The anosmia subjects were surprised when they smelled anything at all, leading to an enhanced P300 response, while the subjects in the visual study were so absorbed in the hallucinated obstruction that perception of the stimulus was reduced. Clinical implications of these two studies are examined. 1987 Hilgard, Ernest R. (1987). Research advances in hypnosis: Issues and methods. International Journal of Clinical and Experimental Hypnosis, 35, 248-264. There are substantial areas of agreement upon the classical phenomena of hypnosis, illustrated by what we now have learned about hypnotic talent, amnesia, hallucinations, analgesia, and dissociative processes. While genuine advances in knowledge about hypnosis have been made in recent decades, differing orienting attitudes have kept some controversy alive, particularly in the interpretation of empirical findings. Differences of interpretation of the phenomenal and behavioral facts are to be expected in the present stage of developmental, cognitive, and social psychology. NOTES The author writes of the "domain of hypnosis" as within the larger domain of social psychology (because it is usually interpersonal); cognitive psychology (because of alterations in perception, imagination, memory, and thought); developmental and personality psychology (because of individual differences); and physiological psychology (because of neurophysiological aspects). In terms of what we know about hypnotic talent, he notes that high hypnotizability is not generally associated with psychopathology; that it may however be associated with a personality measure called absorption; and that there may be some inherited ability (Morgan, 1973). In the author's view, hypnosis is no longer considered simply a response to suggestion, since imagination and/or fantasy are very important. In reviewing evidence of posthypnotic amnesia the author writes, "Subtleties in language require making careful distinctions among concepts such as compliance, suggestion, compulsivity, belief, self-deception, automaticity, the voluntary, the involuntary, and a happening. If these distinctions are glossed over, the choice of words (e.g., substituting compliance for response to suggestion) may give the impression that a finding departs more widely from conventional views than it does. We, too, have found that Ss used varied strategies or skills during amnesia, but this need not deny augmentation by suggestion. "It takes genuinely high Ss to illustrate truly high posthypnotic amnesia... Many of the truly high hypnotizable individuals cannot break amnesia, no matter how hard they try" (p. 253). Regarding the evidence for hypnotic hallucinations and trance logic, the author suggests that trance logic is not a clear concept because the Subject is capable of good logic while tolerating some inconsistencies. "It is ordinary logic to assume that if your hallucination is your own construction, it is you who can influence it by your own wishes. In the rare cases of transparent or diaphanous hallucinations there is still an 'out there' quality. People who report that they see wispy ghosts also see them as 'out there,' so that they qualify as hallucinations. The distinction appears to be one of perception and perception-like experiences within hypnosis rather than of logic" (p. 256). In reviewing the evidence for hypnotic analgesia, the author acknowledges that pain relief is available with other kinds of interventions, or by using other kinds of psychological processes, but that does not diminish the contribution of hypnosis (which has a long and impressive clinical history). Following laboratory studies, it is noted that "the amount of alleviation of pain through hypnosis is positively correlated with the hypnotizability of the candidate for pain reduction. This result is not universally accepted, because some clinicians are convinced that those unsuccessful in hypnotic pain reduction are resisting hypnosis" (p. 256-257). In the present paper he acknowledges but does not review physiological literature on hypnoanalgesia. Regarding the concept of dissociation, the author indicates that he considers it a more useful concept than the concept of trance or hypnotic state "when a person is only slightly or moderately involved in hypnosis ... . The advantage is that dissociations, as compared with altered states, can be described according to limited or more pervasive changes in the cognitive or motor systems that are being activated or distorted through suggestion in the context of hypnosis. Perhaps when all-inclusive enough, such changes can justify the use of the term trance or altered state, but I believe that these terms should be used, if at all, only for those for whom the immersion in the hypnotic experience is demonstrably pervasive" (pp. 258-259). The author goes on to describe his initial discovery of the 'hidden observer' in an experimental context, and to relate the 'hidden observer' to others' earlier observations of a secondary report of an experience previously concealed from S's consciousness (Binet, 1889-1890/1896; Estabrooks, 1957; James, 1899; Kaplan, 1960). "The issues are still being worked on, but as in the case of trance logic the heart of the problem is not whether to speak of a hidden observer, but to recognize that there may be cognitive distortions in hypnosis even while some more realistic information is being processed in parallel, so that everything is not reportable by S" (p. 260). Nash, Michael R.; Lynn, Steven Jay; Stanley, Scott; Carlson, Victor (1987). Subjectively complete hypnotic deafness and auditory priming. International Journal of Clinical and Experimental Hypnosis, 35 (1), 32-40. The present study examined the cognitive and attentional mechanisms by which auditory information is maintained out of awareness during complete hypnotic deafness. Adopting a methodology from recent work on subliminally presented pattern- masked words and dichotic listening, the study tested whether spoken words presented during complete hypnotic deafness affect lexical decisions concerning subsequently presented word choices. The response of 9 hypnotized and 15 simulating Ss to spoken stimulus words presented following hypnotic deafness instructions was compared to the response of 20 baseline control Ss who never were exposed to the stimulus words. While the response pattern of hypnosis Ss appeared different from that of baseline control Ss, hypnotic Ss showed no evidence of the priming effect found in subliminal perception and dichotic listening studies. Simulator response deviated significantly from hypnotized and baseline control responses. NOTES 10 highs capable of hypnotic deafness, screened by Harvard Group and Stanford Profile Scales (Means 11.0 and 24.7, respectively) and 15 lows (means 1.7 and 1.7, respectively) participated in the study; the low hypnotizables being in the simulation group. For the experimental session, a different E administered a standard hypnotic induction and the deafness suggestion, testing for deafness by snapping fingers near S's ear and making loud requests for motor responses. An experimental trial consisted of tapping an S on the hand, saying the stimulus word out loud, and visually presenting four words for the S to read out loud and circle one. "Of the 18 main experimental trials, the four-word array consisted of two words which were related to the stimulus (one word which was semantically related to the spoken stimulus word and one word which was phonetically related), and two neutral unrelated words" (p. 34). For example, if the spoken word were 'dream,' the word array might include 'cream, tennis, sell, sleep.' There also were "3 phonetically unrelated trials (whose arrays consisted of one phonetically related choice and 3 unrelated choices) and 2 stimulus word-unrelated trials (whose arrays consisted of the stimulus word and 3 unrelated choices) ... [and] 7 dummy trials with 4 unrelated choices only" (p. 34). Ss rated their degree of deafness on a 10-point scale after hypnosis was terminated. Possible sources of bias were examined by having 20 control Ss respond to blank tachistoscopic slides with the instructions that they were participating in a study of 'subliminal perception.' Another 22 Ss were asked to identify the semantically and phonetically related words from the word array, which for the most part they did successfully. All Ss rated themselves as '10' on the deafness scale, indicating total deafness. The principal results are seen in Tables 1 and 2. Table 1 Mean Number of Related and Unrelated Responses (Percentage of Responses) for all S Groups on the 18 Mean Experimental Trials Response Category S Group N Related Unrelated Total Hypnotized 9 7.22 10.78 18 (40.13%) (59.88$) (100%) Simulating 15 12.13 5.87 18 (67.43%) (32.61%) (100%) Baseline 19 8.79 9.21 18 Controls (48.82%) (51.17%) (100%) Table 2 Mean Number of Phonetic and Semantic Responses within the Related Response Category on the 18 Main Experimental Trials Related Responses S Group Phonetic Semantic Hypnotized 1.78 5.44 (9.89%) (30.24%) Simulating 7.07 5.07 (39.27%) (28.16%) Baseline 4.21 4.58 Controls (23.38%) (25.44%) Hypnotized Ss were significantly different from simulators (Table 1) in number of related responses. Simulators gave significantly more related responses than baseline controls. Simulators also gave more phonetically related words than either the hypnotized or baseline Ss (Table 2); there was no difference between groups on semantically related words. (Authors performed other useful and detailed analyses.) In their Discussion section, the authors note that they did not obtain the expected results of hypnotized Ss producing more related responses than baseline Ss. "In fact, internal analyses of hypnotized and baseline responses revealed that the pattern of choices for hypnotic deaf Ss was opposite to the direction predicted by subception. Hypnotic Ss appeared to avoid phonetically related word choices, even for items on which baseline control Ss scored above chance. ... "This kind of non-baseline performance by hypnotic Ss can be accounted for by either a strategic enactment conceptualization of hypnosis (Spanos, 1982; Wagstaff, 1981) or Hilgard's (1979) neo-dissociation theory. Spanos might emphasize the hypnotic S's active strivings to meet the hypnotist's perceived expectations. ... Neo-dissociation theory might stress the mechanisms by which processing of auditory inputs are maintained outside of awareness via a dissociative barrier. " ... Given the tendency for simulating Ss to 'overplay' hypnotic phenomena (Levitt & Chapman, 1979), one might have expected simulators to pointedly avoid related responses, thus producing a lower frequency of related words than either the hypnotic Ss or the baseline controls (in effect being more deaf than the deaf). Just the opposite occurred. One possible explanation for this behavior presents itself: In their work with posthypnotic suggestion and the 'disappearing hypnotist' ... M. T. Orne and others found that simulating Ss may be more alert and responsive to demand cues than are hypnotic Ss. In the present study, the authors' original hypothesis was that hypnotic Ss might reveal a subception effect by above-chance responding on related word choices. If we assume that this expectation was somehow communicated to Ss by some subtle aspect of the experimental procedure, then it is conceivable that simulating Ss were able to detect and act upon these cues, while hypnotized Ss remained relatively unattuned to such subtleties. "In sum, the priming effect noted in the subliminal perception research does not appear to be a feature of complete hypnotic deafness, at least as measured in this study. The behavior of simulating Ss in the present study should be another caution to researchers that differences between hypnotized and simulating Ss may reflect simulation effects in addition to, or instead of, hypnotic effects" (pp. 37-38). 1985 Spiegel, David; Cutcomb, Steven; Ren, Chuan; Pribram, Karl (1985). Hypnotic hallucination alters evoked potentials. Journal of Abnormal Psychology, 94 (3), 249-255. Brain electrical potentials evoked by visual stimulation were analyzed to study the neurophysiological mechanism associated with hypnotic hallucination. The visual evoked responses of 6 high- and 6 low-hypnotizable subjects were compared in three hypnotic conditions: stimulus enhancement, stimulus diminution, and stimulus elimination (obstructive hallucination). High-hypnotizable individuals demonstrated significant suppression of the later components of the evoked response (N1 and P3) while experiencing obstructive hallucinations, indicating a change in information processing. This effect was significantly greater in the right, as compared to the left, occipital region. NOTES In the stimulus enhancement condition, Ss were told that one of two colored stimuli would appear unusually bright and interesting. In the stimulus diminution condition, Ss were told that the alternate color stimulus would appear drab, dull, uninteresting. In the obstructive hallucination condition, Ss were told to visualize a box that blocked their view of the TV monitor, making it impossible to see anything on the TV screen. The stimuli were 8 cm x 8 cm squares (colored gratings) presented 1 meter in front of S: 50% were blue vertical gratings, 50% were pink horizontal gratings. Ss were told to press a button in response to any stimulus they happened to see; hence all stimuli were potential targets. To control for the effect of motor potentials when they pressed the button, a button-pressing/passive-attention control group was added. Only results significant beyond this control group were attributed to a hypnotic hallucination effect. A second control group of medium level hypnotizable Ss were required to (a) button press after each stimulus presentation and (b) attend passively to the TV monitor screen without button pressing. "Thus, we had three control conditions: (a) for attentional demands, comparing the performance of high hypnotizables in the obstructive hallucination versus the hypnotic stimulus enhancement condition, (b) for hypnotizability, in comparing the high hypnotizables in the obstructive hallucination condition versus the low hypnotizables in the same condition, and (c) for button-pressing behavior, comparing the performance of the high hypnotizables to that of control subjects in press versus no-press conditions" (p. 250). In their discussion, the authors state, "Our results are consistent with the hypothesis that an hypnotic instruction of obstructive hallucination among high- hypnotizable subjects is accompanied by a decrease in the amplitude of the P3 component of the evoked response throughout the brain, and of the N2 and P3 components in the occipital region. This dampening of amplitude is particularly notable among high hypnotizables in the right, as compared with the left, occipital area, suggesting greater inhibition of scalp-recorded response to a visual stimulus in the right hemisphere. "These data show that while experiencing an obstructive hallucination blocking the stimulus, high-hypnotizable subjects demonstrate a change in the information-processing components of the evoked response (Baribeau-Braun, Picton, & Gosselin, 1983), rather than primarily in channel selection, which is reflected more by P1 and N1 (Ford, Roth, Dirk, & Kopell, 1978; Hillyard & Picton, 1979). Although there were differences at P1 and N1 between high and low hypnotizables, they were not significantly greater than those observed in the press/no-press control group. These observations make it possible to address several alternative explanations for the findings, such as the possibility of differences in nonspecific arousal leading to a differential preparation (Naatanen, 1969), which should be reflected primarily in changes in the early components, as would any differences in pupil size. Drowsiness or inattention in this condition should be associated with an increase, rather than a decrease, in response amplitudes (Schacter, 1976). The possibility that high hypnotizables might have defocused their view of the monitor (Schulman-Galambos, & Galambos, 1978) is made less likely by the fact that defocusing is accompanied by increases in P1 latency (Sokol & Moskowitz, 1981), whereas there were no P1 latency differences in the obstructive hallucination condition" (p. 254). Zamansky, Harold S.; Bartis, Scott P. (1985). The dissociation of an experience: The hidden observer observed. Journal of Abnormal Psychology, 94 (3), 243-248. Addressed methodological weaknesses in previous studies of the hidden observer phenomenon presented by E. R. Hilgard (1977) using a modified procedure with 11 undergraduates highly susceptible to hypnosis. The critical modifications were that no prior practice in dissociation was given before the hidden observer was assessed, the notion of hidden information was introduced only after the stimulus was no longer present, and independently verifiable stimuli were employed. Despite this more rigorous procedure, a hidden observer response was still observed in more than 90% of Ss. This finding makes much less tenable interpretations that attribute the hidden observer effect solely to social expectancies and situational demands. It is concluded that it is possible for some hypnotized individuals to monitor the actual state of events while experiencing a variety of perceptual distortions. 1983 Nash, John (1983). Negative visual hallucination and concomitant changes in cortical event-related potentials (Dissertation, University of California, Santa Barbara). Dissertation Abstracts International, 45 (2), 716-B. (Order No. DA 8411224) "The purpose of this investigation was to examine the effects of negative visual hallucination (NVH) on cortical event-related potentials (ERPs), and to compare these effects with those of selectively attending to and ignoring stimuli. Five highly hypnotically susceptible subjects, four female and one male, were trained to block from subjective experience, i.e., negatively hallucinate, a ring of strobe-illuminated circles surrounding a central, independently strobe-illuminated circle. This stimulus array was modeled after part of the Titchener-Ebbinghaus circle illusion, since previous research had shown that subjects could attenuate the effects of the optical illusion via NVH of the outer, illusion-producing circles. "Analysis of the ERP data revealed amplitude and latency changes in various ERP components across the three experimental conditions (Attend, Ignore, NVH) for the four female subjects, a negative result which is explained in motivational terms. "The most noteworthy finding was the selection of the P3 amplitude variable at C2 by stepwise discriminant analysis for the four females, and the fact that this amplitude systematically decreased across conditions from largest in Attend to smallest in NVH. A variety of individual patterns were observed in terms of other ERP components which allowed discrimination (successful classification) among the three conditions. The results suggest that both Ignoring and NVH of a stimulus result in a decrease in the subjective certainty of perception of the stimulus. Individual differences in patterns of ERP changes are interpreted in terms of differing strategies for execution of the experimental instructions. The results support the view that NVH instructions produce distinctive ERP effects and that NVH generally can be viewed as an extreme level of ignoring" (p. 716). 1982 Cunningham, Paul V.; Blum, Gerald S. (1982). Further evidence that hypnotically induced color blindness does not mimic congenital defects. Journal of Abnormal Psychology, 91, 139-143. Six undergraduate women, highly skilled in hypnotic techniques, were trained under hypnosis with a color mixer to experience red, green, blue, and total color blindness and were then programmed for the same responses in the posthypnotic state under conditions of amnesia. After awakening they were shown pseudoisochromatic plates as a preliminary check on the efficacy of the prior hypnotic instructions. The experiment consisted of successive administrations of the Farnsworth-Munsell 100-hue test, initially under normal baseline viewing conditions followed by each of the color-blind conditions in turn. Results indicate that although the observers subjectively experienced the varieties of color blindness as instructed, their responses differed from specimen responses of individuals with congenital defects in color discrimination. Implications for interpreting hypnotic alterations of perception are discussed. Spanos, Nicholas P.; Bridgeman, M.; Stam, H. J.; Gwynn, M. I.; Saad, C. I. (1982-83). When seeing is not believing: The effects of contextual variables on the reports of hypnotic hallucinations. Imagination, Cognition and Personality, 2, 195-209. When administered a hallucination suggestion most high susceptible hypnotic and task-motivated subjects reported that they "saw" the suggested object. When asked what they meant by "saw," however, almost all indicated that they had imagined the object but did not believe that it had actually been present. On the other hand, simulating subjects maintained that the suggested object had been "really there." Simulators were also more likely than non-simulators to provide "life-like" descriptions of the suggested object (e.g., solid rather than transparent, colored, highly vivid). These findings are consistent with the view that hypnotic hallucinations are context-generated imaginings. They also indicate that unique or unusual psychological processes like "trance logic" need not be posited to account for the descriptions of "hallucinatory" experiences proffered by hypnotic subjects. NOTES It was observed that hypnotized Ss reported more vivid (and longer sustained) imagery than task motivated Subjects. Hypnotized Ss did not differ from high susceptible simulators on vividness of imagery or how long they experienced the imagery, but did report shorter and less vivid imagery than simulators who were low hypnotizables. 1981 Blum, Gerald S.; Nash, John; Jansen, Robert D.; Barbour, John S. (1981, June). Posthypnotic attenuation of a visual illusion as reflected in perceptual reports and cortical event-related potentials. Academic Psychology Bulletin, 3, 251-271. Highly selected and trained hypnotic subjects, capable of ablating portions of visual stimuli from conscious awareness, showed varying degrees of ability to attenuate the Titchener-Ebbinghaus circles illusion post-hypnotically under a negative visual hallucination instruction. The presence or absence of such inhibitory skill, inferred from perceptual reports, was differentially reflected in changes in cortical event-related potentials not typically associated with shifts in selective attention. These findings point to the cognitive operation of a distinctive mechanism of selective inattention. NOTES Blum et al. postulate an inhibitory mechanism of the central nervous system with stages of amplification and attenuation. They suggest that individual differences in inhibitory skill may be improved with practice even for very skilled Subjects. They studied this type of inhibition using a visual illusion (the Titchener-Ebbinghaus circles) because the neural locus of such illusions is thought to be more central in the nervous system rather than at the level of the retina. Experiment 1. Three Ss trained in using hypnosis viewed stimuli in waking and posthypnotic negative visual hallucination (NVH) conditions. All three had previously passed a negative hallucination item (not seeing a playing card of three such cards placed on a table). Training included practice sessions applying NVH to the experimental stimuli. S1 reported immediate success; S2 experienced some initial difficulty ("I have a feeling something's there") but then reported success; S3 required a couple of long practice sessions. The classic Titchener-Ebbinghaus illusion stimuli were used. Stimuli were ten slides with drawings of a standard 17-mm-diameter black circle on the left and a comparison black circle on the right. The black circle on the right was either 14, 15, 16, 17, or 18 mm in diameter, skewed intentionally around 17, to compensate for the proportion of smaller and larger judgments applied to the comparison figure in relation to the standard. One black comparison figure was surrounded by seven 15-mm diameter white circles; the other by seven 10 mm diameter white circles. The key drawings were both black circles of 17 mm. The second set of five drawings, used as a control, contained the same black circles but lacked outer rings of white circles. The Subject was to state whether the black circle on the right appeared larger, smaller, or the same as the standard black circle on the left. Slides were shown for 4 seconds each, with 6 seconds in between slides. Alternating blocks of trials were given under baseline (B) condition and a posthypnotically programmed negative hallucination condition (NVH). In the NVH condition, "the rings of white circles surrounding the standard and comparison black inner circles were 'ablated' from consciousness. The observers were amnesic in the waking state for their prior hypnotic instructions and were cued in advance of a block of trials simply by the phrases 'This will be a mixed series' (referring to B, in which the stimuli appeared as they really were, some with outer rings of white circles present and others not), or 'This will be a black only series' (referring to NVH, in which all stimuli appeared to the observer as black circles only, whether the outer rings were physically present or not)" (pp. 254- 255). Sessions were spread out over 8-12 months for each observer, interspersed with a variety of other experiments. In one session the Experimenters used a selective attention instruction, with Ss given posthypnotic suggestions to regulate their cognitive arousal to a peak of mental alertness and concentration (+AA) and focus on the inner black circles but not to negatively hallucinate the outer white circles. Although all three Ss showed the illusion effect, they varied in ability to attenuate the illusion when negative visual hallucination suggestions were given. "S1 showed a very greatly reduced frequency of reports in the illusory direction under the NVH condition, a less marked reduction under +AA concentration, and no reduction at all under a waking instruction to ignore the outer circles; S2 revealed a moderate but significant reduction under NVH but not under +AA; S3 gave no evidence of attenuation in either condition" (p. 258). The response times for the two more successful Ss (1 and 2) with the 17 mm stimuli under NVH conditions were not different when the outer circles were either present or absent. Experiment 2. The next year S1 and S2 returned but S3 was no longer available as a Subject; S4 and S5 were added and trained in hypnosis skills. EEG evoked response potentials (ERPs) were recorded while Ss made size judgments as in Experiment 1. Averaged ERPs for each block of 100 stimulus presentations were obtained for the first 500 milliseconds following stimulus onset. Judges blind to the experimental conditions evaluated the ERP records. All Subjects experienced the Titchener-Ebbinghaus illusion, but again there were individual differences in ability to attenuate the illusion: S1 was the most successful; S2 gave significantly fewer responses in the larger category under NVH than B conditions; and both S1 and S2 improved attenuation performance over the previous year. S4 fell between S1 and S2 in ability; S5 was unable to attenuate the illusion in the NVH condition. Results. "All three observers whose perceptual reports indicated some attenuation of the visual illusion during the NVH condition also showed a consistent reduction of the P2-N2 amplitude during NVH" (p. 262) at the Occipital sites. Median amplitude reduction was 36%, 40%, and 36% for S1, S2, and S4; only 7% for S5. There were no similar reductions for the other electrode sites, though "enhancement of P2-N2 amplitudes occurred in the lateral prefrontal and frontal areas in the two most successful individuals, S1 and S4" (p. 263). There was also a lag in N2 peak latencies for the three best subjects. The Experimenters noted that the N2 peak occurred 50 msec later in the frontal and prefrontal areas than in the occipital area. In their Discussion, the authors express the view that it is not likely that faking could have occurred, for several reasons: 1. The Subjects were trained to report honestly, and they often had reported failures to experience hypnotic phenomena suggested during training sessions. 2. The task elicited rapid responses, usually in less than 2 seconds, to 10 different slides in randomized blocks of 100 trials, which would make self monitoring of responses extremely difficult. 3. Subjects exhibited a consistency of responses over experimental sessions that were widely separated in time, making conscious or unconscious deception unlikely. 4. The finding of no difference in latency between 17 mm stimuli with and without outer rings of white circles supports an interpretation of reliable reporting. 5. Differences in ERP data between the B and NVH conditions were obtained only for those Ss who successfully attenuated the illusion. The authors also state, "In terms of our conceptual model of the mind, inhibitory skill is attributable to the capacity for invoking inhibitory action earlier in the sequence as signals are processed through stages of amplification and attenuation en route to consciousness (Blum & Barbour, 1979). In the NVH condition of the present task, first- stage attenuation ... [Subject 1] ... occurs in time to negate the illusion as well as preventing conscious awareness of the outer white circles, second-stage attenuation takes place too late to disrupt the illusion but still in time to keep the outer circles from consciousness" (p. 265). Note that the unsuccessful Subject 5 had the highest score on the screening hypnotizability tests. The variation among very high hypnotizables casts doubt on the practice of grouping Ss who score between 9 and 12 on the SHSS. "It is perhaps not surprising that many previous hypnotic studies involving alterations in such subtle phenomena as visual illusions have yielded negative results." p. 266. N.B. None of the Ss was able to eliminate the illusion under a strong waking instruction to ignore the outer circles while judging the inner black ones. "These different results for AA and NVH instructions pinpoint the contrast between selective attention (+AA) and selective inattention (NVH)" (p. 266). The ERP changes seen in occipital and frontal areas were in opposite directions. Thus "the data suggest an effect which seems to parallel both investment of attention (increases in late components over frontal cortex) and withdrawal of attention (relative decreases in late components over occipital cortex). This parallel leads us to speculate that our occipital decreases may have been due to active inhibition of information-processing in the occipital regions, and that the late component enhancement over frontal areas may have been due to the mobilization of resources in these areas necessary to accomplish the tonic inhibition of visual input. ... Activity in the frontal cortex apparently 'programs' inhibition on the specific sensory nuclei of the thalamus, in a modality specific and topographical way, accomplishing gating of sensory information to primary sensory cortex" (p. 268). 1980 Bauer, Herbert; Berner, Peter; Steinringer, Hermann; Stacher, Georg (1980). Effects of hypnotic suggestions of sensory change on event-related cortical slow potential shifts. Archiv fur Psychologie, 133 (3), 161-169. "The purpose of this study was to evaluate whether cortical slow potentials related to a S1-S2 paradigm are influenced by hypnotic suggestions of sensory change. Five healthy subjects susceptible to hypnosis participated each in two identical experiments with three conditions. In condition (1) and (2) each three intensities of 800 and 4000 Hz tones were presented. Preceding condition (2) hypnosis was induced and the subjects received the suggestion to hear the 800 but not the 4000 Hz tones. In condition (3), the tones were presented as S1 and a flash as S2. The subjects received the same suggestions as in (2) and a motor response to S2 was required. EEG was recorded from Cz. In (1) 800 and 4000 Hz tones caused negativities of equal amplitude, in (2) only minute negativities developed, possibly due to hypnosis induced deactivation. In (3) the S1-S2 related negativities were significantly smaller in amplitude during 4000 Hz tones than during 800 Hz tones, while the negativities preceding S2 differed only after the most intense S1. Hypnotic suggestions attenuate S1-S2 related negative potentials, possibly by affecting cognitive functions. Erickson, Milton H. (1980). Hypnotic alteration of sensory, perceptual and psychophysical processes. (2 ). New York: Irvington Publishers, Inc.. NOTES: This second volume of four has five sections, with chapters as follows. I. Visual Processes 1. The hypnotic induction of hallucinatory color vision followed by pseudonegative afterimages (written with E. M. Erickson) 2. Discussion: Critical comments on Hibler's presentation of his work on negative afterimages of hypnotically induced hallucinated colors (written by E. M. Erickson) 3. The induction of color blindness by a technique of hypnotic suggestion 4. An experimental investigation of the hypnotic subject's apparent ability to become unaware of stimuli 5. The development of an acute limited obsessional hysterical state in a normal hypnotic subject 6. Observations concerning alterations in hypnosis of visual perceptions (written by E. M. Erickson) 7. Further observations on hypnotic alteration of visual perception (written by E. M. Erickson) 8. An investigation of optokinetic nystagmus 9. Acquired control of pupillary responses II. Auditory Processes 10. A study of clinical and experimental findings on hypnotic deafness: I. Clinical experimentation and findings 11. A study of clinical and experimental findings on hypnotic deafness: II. Experimental findings with a conditioned response technique 12. Chemo-anaesthesia in relation to hearing and memory 13. A field investigation by hypnosis of sound loci importance in human behavior III. Psychophysiological Processes 14. Hypnotic investigation of psychosomatic phenomena: Psychosomatic interrelationships studied by experimental hypnosis 15. Hypnotic investigation of psychosomatic phenomena: The development of aphasialike reactions from hypnotically induced amnesias (written with R. M. Brickner) 16. Hypnotic investigation of psychosomatic phenomena: A controlled experimental use of hypnotic regression in the therapy of an acquired food intolerance 17. Experimentally elicited salivary and related responses to hypnotic visual hallucinations confirmed by personality reactions 18. Control of physiological functions by hypnosis 19. The hypnotic alteration of blood flow: An experiment comparing waking and hypnotic responsiveness 20. A clinical experimental approach to psychogenic infertility 21. Breast development possibly influenced by hypnosis: Two instances and the psychotherapeutic results 22. Psychogenic alteration of menstrual functioning: Three instances 23. The appearance in three generations of an atypical pattern of the sneezing reflex 24. An addendum to a report of the appearance in three generations of an atypical pattern of the sneezing reflex IV. Time Distortion 25. Time distortion in hypnosis, I (written by L. F. Cooper) 26. Time distortion in hypnosis, II (written with L. F. Cooper) 27. The clinical and therapeutic applications of time distortion 28. Further considerations of time distortion: Subjective time condensation as distinct from time expansion (written with E. M. Erickson) V. Research Problems 29. Clinical and experimental trance: Hypnotic training and time required for their development 30. Laboratory and clinical hypnosis: The same or different phenomena? 31. Explorations in hypnosis research (with a discussion by T. X. Barber, R. Dorcus, H. Guze, T. Sarbin, and A. Weitzenhoffer) 32. Expectancy and minimal sensory cues in hypnosis 33. Basic psychological problems in hypnotic research 34. The experience of interviewing in the presence of observers Wallace, Benjamin (1980). Autokinetic movement of an imagined and an hypnotically hallucinated stimulus. International Journal of Clinical and Experimental Hypnosis, 28 (4), 386-393. Autokinetic movement (AKM) of an imagined or an hallucinated stimulus was assessed as a function of hypnotic susceptibility level. 3 groups of Ss were asked to produce an image of a small, pinpoint spot of light and to monitor any activity of the stimulus. The stimulus was produced by imagination for a group of Ss judged high in hypnotic susceptibility and for a second group of Ss judged low in hypnotic susceptibility. A third group of Ss, highly susceptible to hypnosis, was asked to hallucinate the pinpoint spot stimulus with the aid of instructions administered by E. Instructions by which movement reports were elicited were kept equal and open-ended for all 3 groups of Ss. Results indicated that form of the stimulus (imagined or hallucinated) did not affect reports of AKM. Hypnotic susceptibility level, however, was a major factor in influencing resultant reports. The Ss judged high in hypnotic susceptibility reported a significantly greater number of direction changes of AKM than Ss low in hypnotic susceptibility. The data are interpeted in terms of the possible differences in stimulus monitoring ability as a function of hypnotic susceptibility level. 1979 Karlin, Robert A. (1979). Hypnotizability and attention. Journal of Abnormal Psychology, 88 (1), 92-95. An attentional explanation of cognitive hypnotic phenomena (e.g., hallucinations and amnesia) based on the ability to shift the pertinence of stored information was developed. It was hypothesized that individuals who were successful at a difficult attentional task would also succeed on cognitive hypnotic items. The Harvard Group Scale of Hypnotic Susceptibility, Form A was used to assess hypnotizability. To measure pertinence-shift ability, two tape recordings made by the same person were played through a single sound source. One tape was designated the target tape. Amount remembered and perceived task ease were summed to form an additive score of task success. Subjects above the median on the task were assigned to the good pertinence shift group (GP); those below the median were assigned to the poor pertinence shift group (PP). As predicted, GP subjects passed significantly more cognitive hypnotic items than did PP subjects (p<.05). When task difficulty and compliance were controlled for, the results remained significant (p<.05). These results were replicated in a second study. NOTES 1: A brief version of this paper was presented at the Annual Meeting of the Society for Clinical and Experimental Hypnosis, Asheville, North Carolina, October, 1978