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The emerging neuroscience of hypnosis
... A review of Figure 1 reveals that a great deal of activity was devoted to scale development in the 1960s. Despite the continued progress on research on basic mechanisms of hypnosis, its clinical application, and exploration of its features from a cognitive neuroscience perspective (Oakley & Halligan, 2009, there has not been reciprocal development in the area of measurement (Terhune & Cohen Kadosh, 2012;Woody & Barnier, 2008). Thus, the most recent introduction of a novel, standalone measure of hypnotic suggestibility was the SHSS:C nearly 60 years ago, which is widely referred to as the "gold standard" in the field (Kihlstrom, 2008). ...
The most well-established finding gleaned from decades of experimental hypnosis research is that individuals display marked variability in responsiveness to hypnotic suggestions. Insofar as this variability impacts both treatment outcome in therapeutic applications of hypnosis as well as responsiveness to suggestions in experimental contexts, it is imperative that clinicians and researchers use robust measures of hypnotic suggestibility. The current paper critically evaluates contemporary measures of hypnotic suggestibility. After reviewing the most widely used measures, we identify multiple properties of these instruments that result in the loss of valuable information, including binary scoring and single-trial sampling, and hinder their utility, such as the inclusion of suboptimal suggestion content. The scales are not well-suited for contemporary research questions and have outlived their usefulness. We conclude by outlining ways in which the measurement of hypnotic suggestibility can be advanced.
... A review of Figure 1 reveals that a great deal of activity was devoted to scale development in the 1960s. Despite the continued progress on research on basic mechanisms of hypnosis, its clinical application, and exploration of its features from a cognitive neuroscience perspective (Oakley & Halligan, 2009, there has not been reciprocal development in the area of measurement (Terhune & Cohen Kadosh, 2012;Woody & Barnier, 2008). Thus, the most recent introduction of a novel, standalone measure of hypnotic suggestibility was the SHSS:C nearly 60 years ago, which is widely referred to as the "gold standard" in the field (Kihlstrom, 2008). ...
The most well-established finding gleaned from decades of experimental hypnosis research is that individuals display marked variability in responsiveness to hypnotic suggestions. Insofar as this variability impacts both treatment outcome in therapeutic applications of hypnosis as well as responsiveness to suggestions in experimental contexts, it is imperative that clinicians and researchers use robust measures of hypnotic suggestibility. The current paper critically evaluates contemporary measures of hypnotic suggestibility. After reviewing the most widely used measures, we identify multiple measurement properties of these instruments that result in the loss of valuable information, including binary scoring and single-trial sampling, and hinder their utility, such as the inclusion of sub-optimal suggestion content. The scales are not well-suited for contemporary research questions and have outlived their usefulness. We conclude by outlining ways in which the measurement of hypnotic suggestibility can be advanced.
... Hypnosis consists of a set of procedures including an induction and one or more suggestions (Oakley and Halligan, 2009;Terhune and Cohen Kadosh, 2012a). Inductions vary but generally involve instructions and suggestions to promote minimized awareness of one's environment, reduced metacognition, and perceived effortless attention towards the instructions of the experimenter (Brown, Antonova, Langley, and Oakley, 2001). ...
... When the hypnotic state is entered, verbal instructions can be given to elicit changes in perception, experience, behavior, actions, affect, or cognition (Terhune & Kadosh, 2012). These are also referred to as suggestions. ...
... Experimental hypnosis research critically depends on the robust measurement of hypnotic suggestibility (Woody and Barnier, 2008): hypnotic suggestibility scales are essential for reliably identifying highly suggestible individuals and relating hypnotic suggestibility to cognitive and neurophysiological variables. Despite their many strengths, the most widely used measures of hypnotic suggestibility are outdated (Bowers, 1993;Shor and Orne, 1962;Weitzenhoffer and Hilgard, 1962) and have a number of significant limitations pertaining to the mode of measurement and suggestion content (Bowers et al., 1988;Sadler and Woody, 2004;Terhune, 2015;Terhune and Cohen Kadosh, 2012;Woody and Barnier, 2008). These measurement properties may reduce the precision of estimates of hypnotic suggestibility and will be especially problematic in studies where responsiveness to individual suggestions is measured (Bryant et al., 2012;Dienes and Hutton, 2013), and thus plausibly contribute to the difficulties in identifying reliable correlates of hypnotic suggestibility. ...
Hypnosis is a unique form of top-down regulation in which verbal suggestions are capable of eliciting pronounced changes in a multitude of psychological phenomena. Hypnotic suggestion has been widely used both as a technique for studying basic science questions regarding human consciousness but also as a method for targeting a range of symptoms within a therapeutic context. Here we provide a synthesis of current knowledge regarding the characteristics and neurocognitive mechanisms of hypnosis. We review evidence from cognitive neuroscience, experimental psychopathology, and clinical psychology regarding the utility of hypnosis as an experimental method for modulating consciousness, as a model for studying healthy and pathological cognition, and as a therapeutic vehicle. We also highlight the relationships between hypnosis and other psychological phenomena, including the broader domain of suggestion and suggestibility and conclude by identifying the most salient challenges confronting the nascent cognitive neuroscience of hypnosis and outlining future directions for research on hypnosis and suggestion.
... We propose that hypnotic paralysis yields a useful possibility to investigate the neural correlates of the subjective experience of wanting to move. Hypnosis is a genuine and robust phenomenon and can be reliably induced in susceptible individuals (see Halligan & Oakley, 2013;Raz, 2011;Raz & Shapiro, 2002;Terhune & Kadosh, 2012). Hypnosis is a state of altered attention in which susceptible individuals respond particularly well to suggestions. ...
The distinct feeling of wanting to act and thereby causing our own actions is crucial to our self-perception as free human agents. Disturbances of the link between intention and action occur in several disorders. Little is known, however, about the neural correlates of wanting or intending to act. To investigate these for simple voluntary movements, we used a paradigm involving hypnotic paralysis and functional magnetic resonance imaging. Eight healthy women were instructed to sequentially perform left and right hand movements during a normal condition, as well as during simulated weakness, simulated paralysis and hypnotic paralysis of the right hand. Right frontopolar cortex was selectively hypoactivated for attempted right hand movement during simulated paralysis while it was active in all other conditions. Since simulated paralysis was the only condition lacking an intention to move, the activation in frontopolar cortex might be related to the intention or volition to move.
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... It is noteworthy that suggestions comparable to those in the AG profile are not represented on the HGSHS:A (Shor & Orne, 1962), SHSS:C (Weitzenhoffer & Hilgard, 1962), or WSGC (Bowers, 1993; see also Moran, Kurtz, & Strube, 2002), the most commonly used measures of hypnotic suggestibility, whereas the latter two scales include two items that are equivalent to suggestions on the DR profile, which was here shown to lack discriminant validity. In addition to reinforcing the claim that the standard scales of hypnotic suggestibility are poorly suited to the task of delineating individual differences in high hypnotic suggestibility (Terhune & Cohen Kadosh, 2012;Terhune et al., 2011b), these results further suggest that greater representation of agnosia and inhibitory cognitive suggestions in future measures of hypnotic suggestibility will optimize the measurement of response variegation in this population. ...
Diagnosable only through a healthcare professional, Muscle Tension Dysphonia (MTD) is a compensatory muscle hyperfunction of the laryngeal mechanism. A significant cause of this singing voice disorder is anxiety and is symptomatic of inefficient neuromuscular patterns in the larynx. Numerous noninvasive studio voice modalities treat or reduce the muscular and phonatory symptoms of MTD, but a more systemic treatment of underlying mental causes may be considered. Recent studies have shown positive psychological and neuromuscular implications using hypnosis. This paper argues using hypnosis and autohypnosis as a top-down approach to anxiety-induced MTD.
Despite its many influences on numerous features of human behavior and consciousness, suggestibility, the ubiquitous disposition to generate and modify experiences, thoughts, and actions remains one of the least researched aspects of human cognition. As a critical feature of hypnosis, much research on suggestion and suggestibility has understandably focused on hypnotic suggestion with comparatively little exploration of the larger rich domain of suggestibility. From a research perspective, suggestibility, can be regarded as comprising a range of bio–psycho–social processes that facilitate or enhance the probability of a suggestion being accepted and believed. Suggestion, on the other hand, can be seen as a form of communicable ideation or belief, that once accepted has the capacity, (like other strong beliefs) to exert profound changes on a person’s mood, thoughts, perceptions, and ultimately their behaviors. Although studies of hypnotic suggestion have historically provided much productive research, the comparative neglect of the broader domain of suggestion seems surprising, given its demonstrable potential as a causal explanatory framework for many aspects of human behavior from the placebo effect to advertising. In addition to discerning the potential adaptive value(s) of suggestibility, it is now timely, given the growing interest from neuroscience in hypnotic suggestion, to revisit previous attempts to elucidate potential shared underlying psychological properties.
Hypnosis uses the powerful effects of attention and suggestion to produce, modify and enhance a broad range of subjectively compelling experiences and behaviours. For more than a century, hypnotic suggestion has been used successfully as an adjunctive procedure to treat a wide range of clinical conditions. More recently, hypnosis has attracted a growing interest from a cognitive neuroscience perspective. Recent studies using hypnotic suggestion show how manipulating subjective awareness in the laboratory can provide insights into brain mechanisms involved in attention, motor control, pain perception, beliefs and volition. Moreover, they indicate that hypnotic suggestion can create informative analogues of clinical conditions that may be useful for understanding these conditions and their treatments.
Much effort has been made to understand the role of attention in perception; much less effort has been placed on the role attention plays in the control of action. Our goal in this chapter is to account for the role of attention in action, both when performance is automatic and when it is under deliberate conscious control. We propose a theoretical framework structured around the notion of a set of active schemas, organized according to the particular action sequences of which they are a part, awaiting the appropriate set of conditions so that they can become selected to control action. The analysis is therefore centered around actions, primarily external actions, but the same principles apply to internal actions—actions that involve only the cognitive processing mechanisms. One major emphasis in the study of attentional processes is the distinction between controlled and automatic processing of perceptual inputs (e.g., Shiffrin & Schneider, 1977). Our work here can be seen as complementary to the distinction between controlled and automatic processes: we examine action rather than perception; we emphasize the situations in which deliberate, conscious control of activity is desired rather than those that are automatic.
The continuing absence of an identifiable physical cause for disorders such as chronic low back pain, atypical facial pain, or fibromyalgia, is a source of ongoing controversy and frustration among pain physicians and researchers. Aberrant cerebral activity is widely believed to be involved in such disorders, but formal demonstration of the brain independently generating painful experiences is lacking. Here we identify brain areas directly involved in the generation of pain using hypnotic suggestion to create an experience of pain in the absence of any noxious stimulus. In contrast with imagined pain, functional magnetic resonance imaging (fMRI) revealed significant changes during this hypnotically induced (HI) pain experience within the thalamus and anterior cingulate (ACC), insula, prefrontal, and parietal cortices. These findings compare well with the activation patterns during pain from nociceptive sources and provide the first direct experimental evidence in humans linking specific neural activity with the immediate generation of a pain experience.
This chapter explains the primary phenomenology of hypnosis with two new accounts of how hypnosis happens. First, it discusses in more detail the phenomena to be explained and the questions that have been addressed. Then, it briefly and selectively reviews previous generations of cognitive theories that have influenced and informed the answers to those questions. This article introduces two new accounts: Dienes and Perner's (2007) cold control theory of hypnosis and Barnier and Mitchell's (2005) discrepancy-attribution theory of hypnotic illusions. Both these accounts have been presented together as they share a number of features, especially their roots in contemporary cognitive psychology. Both of the theoretical accounts that have been presented in this chapter reconsider the role of expectations in hypnosis. And the article argues at least for one of the accounts that hypnotic responses feel like they do, not because they meet expectations, but because they violate them.
Previous studies implicate involvement of dopaminergic systems in hypnotizability and report association with the COMT Val(158)Met single nucleotide polymorphism (SNP, rs4680) demonstrating the Val/Met heterozygotes as the most hypnotizable group using the Stanford Hypnotic Susceptibility Scale. This study replicates that association using an independent sample of 127 healthy Hungarian young adults and the Waterloo-Stanford Group C Scale of Hypnotic Susceptibility. Significant association (p = .016) was found between the COMT genotypes and hypnotizability, with a clear additive effect of the Val allele: Hypnotizability scores were highest in Val/Val (5.9), intermediate in Val/Met (4.7), and lowest in Met/Met (4.1). Differences between these results and those of previous studies support recent findings suggesting an inverted-U-shaped relation between dopamine level in the prefrontal cortex and cognitive functioning. The present study replicates association of COMT Val(158)Met SNP and hypnotizability and stresses the importance of mediating factors, such as group vs. individual inductions.
To clarify whether hypnotically-induced alexia was able to reduce the Stroop effect due to color/word interference, 12 volunteers (6 with high and 6 with low hypnotizability according to Stanford Hypnotic Susceptibility Scale Form C) underwent a Stroop test consisting of measuring, both in basal conditions and during post-hypnotic alexia, the reaction times (RT) at appearance of a colored word indicating a color. In basal conditions, RT were greater in case of incongruence. In highly hypnotizable participants, the interference was less pronounced during post-hypnotic alexia (-34%, p = 0.03). During alexia, late positive complexamplitude was also greater for congruent than incongruent conditions (p < 0.03), and cardiovascular response to stress was less pronounced as well. In participants showing low hypnotizability, no reduction of Stroop effect was detected during post-hypnotic alexia. Posthypnotic alexia is therefore a real and measurable phenomenon, capable of reducing the color-word interference and the haemodynamic effects of the Stroop test.
The growing acceptance of consciousness as a legitimate field of enquiry and the availability of functional imaging has rekindled research interest in the use of hypnosis and suggestion to manipulate subjective experience and to gain insights into healthy and pathological cognitive functioning. Current research forms two strands. The first comprises studies exploring the cognitive and neural nature of hypnosis itself. The second employs hypnosis to explore known psychological processes using specifically targeted suggestions. An extension of this second approach involves using hypnotic suggestion to create clinically informed analogues of established structural and functional neuropsychological disorders. With functional imaging, this type of experimental neuropsychopathology offers a productive means of investigating brain activity involved in many symptom-based disorders and their related phenomenology.
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.
Hypnotic responses have been attributed to 2 mechanisms that are characterized as dissociative. In E. R. Hilgard's (1986) neodissociation theory, responses are hypothesized to be due to a division of consciousness into 2 or more simultaneous streams, separated by an amnesic barrier that prevents access to suggestion-related executive functions, monitoring functions, or both. In K. S. Bowers's (1992) dissociated control theory, hypnotic inductions are hypothesized to weaken frontal control of behavioral schemas, thereby allowing direct activation of behavior by the hypnotist's suggestions. The authors review the empirical base, conceptual issues, and strengths and weaknesses of both theories.
Hypnotic and nonhypnotic suggestibility were investigated in 2 experiments. In Experiment 1, nonhypnotic suggestibility was suppressed when measured after hypnotic suggestibility, whereas hypnotic suggestibility was not affected by the order of assessment. Experiment 2 confirmed a small but significant effect of hypnosis on suggestibility when nonhypnotic suggestibility was measured first. Nonhypnotic suggestibility was correlated with absorption, fantasy proneness, motivation, and response expectancy, but only expectancy predicted suggestibility when the other variables were controlled. Behavioral response to hypnosis was predicted by nonhypnotic suggestibility, motivation, and expectancy in a model accounting for 53% of the variance. Experiential response to hypnotic suggestion was predicted only by nonhypnotic suggestibility. Unexpectedly, hypnosis was found to decrease suggestibility for a substantial minority of participants.
Only recently have studies of electrocortical activity, event-related potentials, and regional cerebral blood flow begun to shed light on the anatomical and neurobiological underpinnings of hypnosis. Since twin studies show a significant heritable component for hypnotizability, we were prompted to examine the role of a common, functional polymorphism in contributing to individual differences in hypnotizability. A group of 109 subjects (51 male, 59 female) were administered three psychological instruments and tested for the high/low enzyme activity COMT val-->met polymorphism. We observed a significant correlation between hypnotizability measured by the Stanford Hypnotic Susceptibility Scale (SHSS:C), ability to partition attention (Differential Attentional Processes Inventory or DAPI), and absorptive capacities (Tellegen Absorption Scale or TAS). The effect of COMT on the various dependent variables was initially examined by multivariate analysis that corrects for multiple testing. The dependent variables were SHSS:C hypnotizability scores, four attentional subscales of the DAPI, and TAS total score grouped by the COMT genotype (val/val, val/met, met/met) as the independent variable. Hotelling's Trace statistic was significant when scores were grouped by the COMT genotype (Hotelling's T(2) = 1.88, P = 0.04. Post-hoc testing using the Bonferroni correction shows that the only significant difference is between the val/met vs. the val/val COMT genotypes on hypnotizability. This association was significant for men but not for women. As for all case-control studies, these results need to be interpreted cautiously and require replication. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:771-774, 2000.
Hypnosis has been used clinically for hundreds of years and is primarily a phenomenon involving attentive receptive concentration. Cognitive science has not fully exploited hypnosis and hypnotic suggestion as experimental tools. This study was designed to determine whether a hypnotic suggestion to hinder lexical processing could modulate the Stroop effect.
Behavioral Stroop data were collected from 16 highly suggestible and 16 less suggestible subjects; both naturally vigilant and under posthypnotic suggestion. Subjects were urged to only attend to the ink color and to impede reading the stimuli under posthypnotic suggestion.
Whereas posthypnotic suggestion eliminated Stroop interference for highly suggestible subjects, less suggestible control subjects showed no significant reduction in the interference effect.
This outcome challenges the dominant view that word recognition is obligatory for proficient readers, and may provide insight into top-down influences of suggestion on cognition.
4 principles, or criteria, are suggested for the hypnotic induction of psychopathology: the induced process must not include cues as to how E expects the S to respond in any other respect; (b) the induced process must be response-producing, (c) some of the produced responses must fit the criteria for inclusion in some classification of psychopathology; and (c) some of the Ss must be asked by a co-experimenter, unknown to the E, to fake hypnosis in order to determine the demand characteristics of the research. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
One hundred and seven healthy volunteers were administered Cloninger's Tridimensional Personality Questionnaire (TPQ), the Differential Attentional Processes Inventory (DAPI), the Tellegen Absorption Scale (TAS), and the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). Polymorphisms of catechol O-methyltransferase (COMT), an enzyme involved in dopamine metabolism, were assessed. Highly hypnotizable subjects self-reported greater TPQ persistence, absorption, and focused attentional abilities. Hierarchical multiple regression analyses found that TPQ persistence, COMT, TAS, and the DAPI attentional scales explained 43.8% of the variance in women and 29% in men. Membership was correctly discriminated for the more extreme low (62.1%) and highly (81.5%) hypnotizable groups. These results suggest that highly hypnotizable persons have a more effective frontolimbic attentional system and further suggest the involvement of dopaminergic systems in hypnotizability.
This is the first MRI study to report differences in brain structure size between low and highly hypnotizable, healthy, right-handed young adults. Participants were stringently screened for hypnotic susceptibility with two standardized scales, and then exposed to hypnotic analgesia training to control cold pressor pain. Only the highly hypnotizable subjects (HHs) who eliminated pain perception were included in the present study. These HHs, who demonstrated more effective attentional and inhibitory capabilities, had a significantly (P < 0.003) larger (31.8%) rostrum, a corpus callosum area involved in the allocation of attention and transfer of information between prefrontal cortices, than low hypnotizable subjects (LHs). These results provide support to the neuropsychophysiological model that HHs have more effective frontal attentional systems implementing control, monitoring performance and inhibiting unwanted stimuli from conscious awareness, than LHs.
Hypnosis involves the manipulation of conscious attentional discrimination. The prepulse inhibition (PPI) paradigm assesses primary unconscious information processing. We investigated the correlation between hypnotizability and PPI of the startle reflex. Forty-eight healthy subjects were evaluated with the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) and acoustic PPI. Subjects were divided into low, medium, and high hypnotizable groups. The low-hypnotizable group showed a significantly higher inhibition of the startle response, at lead intervals 60 ms and 120 ms, than did the medium- and high-hypnotizable groups. We conclude that hypnotizability and PPI may be negatively correlated. These findings lend further support for the role of dopaminergic neurotransmission mechanisms in the determination of hypnotizability levels.
contrast 2 psychological views of dissociation / [the "bogey tale"] view of dissociation starts with the assumption that mental processes normally represent some kind of unity / however, this unity may be uncharacteristically disrupted by an unusual and special mechanism (dissociation), in which mental processes become divided / the 2nd [Stevensonian] view of dissociation begins with the assumption that some multiplicity of mental process is typical and normal, in the sense of coexisting levels of control that are usually well-coordinated by higher conscious functioning / circumstances in which dissociation becomes evident, therefore, are ones in which this higher functioning is weakened, laying bare some of the underlying "multifarious" architecture of the mind
apply these conceptions of dissociation to an understanding of hypnosis / [propose] a dissociated-control view of hypnotic amnesia / [relate] the dissociated-control theory to some current cognitive and neuropsychological models of mental functioning / aims are both to substantiate the plausibility of such a theory, and in the process of fleshing it out, to suggest some novel directions for further work / link a dissociated-control theory of hypnosis to the inhibition of functions subserved by the prefrontal cortex / [draws some parallels between] the hypnotized S [and] a frontal lobe patient (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Brain mechanisms underlying hysterical conversion symptoms are still poorly known. Recent hypotheses suggested that activation of motor pathways might be suppressed by inhibitory signals based on particular emotional situations. To assess motor and inhibitory brain circuits during conversion paralysis, we designed a go–nogo task while a patient underwent functional magnetic resonance imaging (fMRI). Preparatory activation arose in right motor cortex despite left paralysis, indicating preserved motor intentions, but with concomitant increases in vmPFC regions that normally mediate motivational and affective processing. Failure to execute movement on go trials with the affected left hand was associated with activations in precuneus and ventrolateral frontal gyrus. However, right frontal areas normally subserving inhibition were activated by nogo trials for the right (normal) hand, but not during go trials for the left hand (affected by conversion paralysis). By contrast, a group of healthy controls who were asked to feign paralysis showed similar activation on nogo trials and left-go trials with simulated weakness, suggesting that distinct inhibitory mechanisms are implicated in simulation and conversion paralysis. In the patient, right motor cortex also showed enhanced functional connectivity with the posterior cingulate cortex, precuneus, and vmPFC. These results suggest that conversion symptoms do not act through cognitive inhibitory circuits, but involve selective activations in midline brain regions associated with self-related representations and emotion regulation.
The neuropsychological status of pain conditions such as fibromyalgia, commonly categorized as 'psychosomatic' or 'functional' disorders, remains controversial. Activation of brain structures dependent upon subjective alterations of fibromyalgia pain experience could provide an insight into the underlying neuropsychological processes. Suggestion following a hypnotic induction can readily modulate the subjective experience of pain. It is unclear whether suggestion without hypnosis is equally effective. To explore these and related questions, suggestions following a hypnotic induction and the same suggestions without a hypnotic induction were used during functional magnetic resonance imaging to increase and decrease the subjective experience of fibromyalgia pain. Suggestion in both conditions resulted in significant changes in reported pain experience, although patients claimed significantly more control over their pain and reported greater pain reduction when hypnotised. Activation of the midbrain, cerebellum, thalamus, and midcingulate, primary and secondary sensory, inferior parietal, insula and prefrontal cortices correlated with reported changes in pain with hypnotic and non-hypnotic suggestion. These activations were of greater magnitude, however, when suggestions followed a hypnotic induction in the cerebellum, anterior midcingulate cortex, anterior and posterior insula and the inferior parietal cortex. Our results thus provide evidence for the greater efficacy of suggestion following a hypnotic induction. They also indicate direct involvement of a network of areas widely associated with the pain 'neuromatrix' in fibromyalgia pain experience. These findings extend beyond the general proposal of a neural network for pain by providing direct evidence that regions involved in pain experience are actively involved in the generation of fibromyalgia pain.
This study tested the prediction that dissociative tendencies modulate the impact of a hypnotic induction on cognitive control in different subtypes of highly suggestible individuals. Low suggestible (LS), low dissociative highly suggestible (LDHS), and high dissociative highly suggestible (HDHS) participants completed the Stroop color-naming task in control and hypnosis conditions. The magnitude of conflict adaptation (faster response times on incongruent trials preceded by an incongruent trial than those preceded by a congruent trial) was used as a measure of cognitive control. LS and LDHS participants displayed marginally superior up-regulation of cognitive control following a hypnotic induction, whereas HDHS participants' performance declined. These findings indicate that dissociative tendencies modulate the influence of a hypnotic induction on cognitive control in high hypnotic suggestibility and suggest that HS individuals are comprised of distinct subtypes with dissimilar cognitive profiles.
This study examined whether the behavioral and electrophysiological correlates of synaesthetic response conflict could be disrupted by posthypnotic suggestion. We recorded event-related brain potentials while a highly suggestible face-color synaesthete and matched controls viewed congruently and incongruently colored faces in a color-naming task. The synaesthete, but not the controls, displayed slower response times, and greater P1 and sustained N400 ERP components over frontal-midline electrodes for incongruent than congruent faces. The behavioral and N400 markers of response conflict, but not the P1, were abolished following a posthypnotic suggestion for the termination of the participant's synaesthesia and reinstated following the cancellation of the suggestion. These findings demonstrate that the conscious experience of synaesthesia can be temporarily abolished by cognitive control.
Among hypnotized subjects passing a challenge suggestion of arm rigidity, how might patterns of motor activity (strategies) contribute to the illusion that the elbow cannot be bent? Kinematic analyses of upper limb and trunk were performed. Nonhypnotized subjects carefully enacted a set of prescribed strategies typifying responses possibly adopted by a hypnotized subject. Profile analysis showed striking heterogeneity of response in hypnotic subjects. Half of participants showed no perceivable strategy consistent with the hypothesis that subjects hallucinate the suggestion and so do not engage the motor periphery. Equally common were subtle oscillations or trembling of the arm implying that motion resembling difficulty in bending was initiated. This can be misperceived as unintentional and thus evidence of inability to bend. The lack of a motor strategy is more consistent with dissociated-control theory, whereas the trembling response is more consistent with social-cognitive and dissociated-experience theories.
The present work aimed at assessing whether the interference exerted by task-irrelevant spatial information is comparable in high- and low-susceptible individuals and whether it may be eliminated by means of a specific posthypnotic suggestion. To this purpose high- and low-susceptible participants were tested using a Simon-like interference task after the administration of a suggestion aimed at preventing the processing of the irrelevant spatial information conveyed by the stimuli. The suggestion could be administered either in the absence or following a standard hypnotic induction. We showed that, outside from the hypnotic context, the Simon effect was similar in high and low-susceptible participants and it was significantly reduced following the posthypnotic suggestion in high-susceptible participants only. These results show that a specific posthypnotic suggestion can alter information processing in high-susceptible individuals and reduce the interfering effect exerted by arrow stimuli.
Brain mechanisms of hypnosis are poorly known. Cognitive accounts proposed that executive attentional systems may cause selective inhibition or disconnection of some mental operations. To assess motor and inhibitory brain circuits during hypnotic paralysis, we designed a go-no-go task while volunteers underwent functional magnetic resonance imaging (fMRI) in three conditions: normal state, hypnotic left-hand paralysis, and feigned paralysis. Preparatory activation arose in right motor cortex despite left hypnotic paralysis, indicating preserved motor intentions, but with concomitant increases in precuneus regions that normally mediate imagery and self-awareness. Precuneus also showed enhanced functional connectivity with right motor cortex. Right frontal areas subserving inhibition were activated by no-go trials in normal state and by feigned paralysis, but irrespective of motor blockade or execution during hypnosis. These results suggest that hypnosis may enhance self-monitoring processes to allow internal representations generated by the suggestion to guide behavior but does not act through direct motor inhibition.
Eighty families including at least one set of twins were studied to determine intrafamily resemblances in hypnotizability. Each available family member was tested separately on the Stanford Hypnotic Susceptibility Scale. A significant intraclass correlation ofr
I
=.63 (N=35,p=.001) was found for monozygotic twins, but the corresponding correlations from same-sexed dizygotic twin pairs and other fraternal pairs did not depart significantly from zero.
Sons showed a significant correlation with fathers (r=.37, N=45,p=.05). Results of ratings on a personality scale showed that the correlation was determined by those sons who were rated as similar to their fathers in personality; sons not rated as similar to their fathers in personality did not resemble their fathers in hypnotizability. Because no such correspondences were found between mothers and daughters, or between children and opposite-sexed parents, a simple genetic interpretation does not appear tenable. The study is continuing.
An auditory hallucination shares with imaginal hearing the property of being self-generated and with real hearing the experience of the stimulus being an external one. To investigate where in the brain an auditory event is "tagged" as originating from the external world, we used positron emission tomography to identify neural sites activated by both real hearing and hallucinations but not by imaginal hearing. Regional cerebral blood flow was measured during hearing, imagining, and hallucinating in eight healthy, highly hypnotizable male subjects prescreened for their ability to hallucinate under hypnosis (hallucinators). Control subjects were six highly hypnotizable male volunteers who lacked the ability to hallucinate under hypnosis (nonhallucinators). A region in the right anterior cingulate (Brodmann area 32) was activated in the group of hallucinators when they heard an auditory stimulus and when they hallucinated hearing it but not when they merely imagined hearing it. The same experimental conditions did not yield this activation in the group of nonhallucinators. Inappropriate activation of the right anterior cingulate may lead self-generated thoughts to be experienced as external, producing spontaneous auditory hallucinations.
Based on reflections on the University of Tennessee Conference on Brain Imaging and Hypnosis, the authors point the field of hypnosis toward a new generation of research that can successfully coordinate multiple methods of inquiry and effectively connect psychological with biological understanding. They examine issues concerning hypnosis as a state, hypnotic susceptibility as a trait, and the psychological processes that underlie hypnotic responses. The article indicates ways in which some old questions can, and need to, be asked in new ways. The authors illustrate how to move toward a neuropsychological understanding of hypnosis by describing the classic suggestion effect and consider candidate psychological mechanisms to explain this effect. They argue that the neuroscience of hypnosis needs to build on a sound psychological foundation and add to, rather than replace, existing levels of analysis.
Hypnosis research has contributed much to the understanding of human behavior and experience, both normal and abnormal. This paper considers ways in which neuroscience approaches may be integrated into hypnosis research to continue and enhance that contribution, as well as further reveal the nature of hypnosis itself. The authors review the influences on and advances in hypnosis research over the last century; illustrate the investigative value of hypnosis to selected phenomena across the areas of doing, feeling, believing, and remembering; and specify elements for the successful integration of neuroscience approaches into hypnosis research. The authors believe that hypnosis research offers powerful techniques to isolate psychological processes in ways that allow their neural bases to be mapped. Successful integration will be achieved when researchers add levels of explanation, rather than shift the emphasis from one level or feature to another.
Recent data indicate that under a specific posthypnotic suggestion to circumvent reading, highly suggestible subjects successfully eliminated the Stroop interference effect. The present study examined whether an optical explanation (e.g., visual blurring or looking away) could account for this finding. Using cyclopentolate hydrochloride eye drops to pharmacologically prevent visual accommodation in all subjects, behavioral Stroop data were collected from six highly hypnotizables and six less suggestibles using an optical setup that guaranteed either sharply focused or blurred vision. The highly suggestibles performed the Stroop task when naturally vigilant, under posthypnotic suggestion not to read, and while visually blurred; the less suggestibles ran naturally vigilant, while looking away, and while visually blurred. Although visual accommodation was precluded for all subjects, posthypnotic suggestion effectively eliminated Stroop interference and was comparable to looking away in controls. These data strengthen the view that Stroop interference is neither robust nor inevitable and support the hypothesis that posthypnotic suggestion may exert a top-down influence on neural processing.
Norms are presented on an adaptation for group administration with self-report scoring of Weitzenhoffer and Hilgard's Stanford Hypnotic Susceptibility Scale, Form A. Comparisons are made between a sample of 132 undergraduates given the new group-administered version and four reference samples including the original Stanford University normative group.Findings indicate that the group-administered version yields norms congruent with the individually-administered original. Diagnostic evaluations of hypnotic depth after one or more additional hypnotic training sessions tentatively indicate that the adapted scale is an effective predictor of subsequent hypnotic depth.
The continuing absence of an identifiable physical cause for disorders such as chronic low back pain, atypical facial pain, or fibromyalgia, is a source of ongoing controversy and frustration among pain physicians and researchers. Aberrant cerebral activity is widely believed to be involved in such disorders, but formal demonstration of the brain independently generating painful experiences is lacking. Here we identify brain areas directly involved in the generation of pain using hypnotic suggestion to create an experience of pain in the absence of any noxious stimulus. In contrast with imagined pain, functional magnetic resonance imaging (fMRI) revealed significant changes during this hypnotically induced (HI) pain experience within the thalamus and anterior cingulate (ACC), insula, prefrontal, and parietal cortices. These findings compare well with the activation patterns during pain from nociceptive sources and provide the first direct experimental evidence in humans linking specific neural activity with the immediate generation of a pain experience.
Hypnosis can profoundly alter sensory awareness and cognitive processing. While the cognitive and behavioral phenomena associated with hypnosis have long been thought to relate to attentional processes, the neural mechanisms underlying susceptibility to hypnotic induction and the hypnotic condition are poorly understood. Here, we tested the proposal that highly hypnotizable individuals are particularly adept at focusing attention at baseline, but that their attentional control is compromised following hypnosis due to a decoupling between conflict monitoring and cognitive control processes of the frontal lobe. Employing event-related fMRI and EEG coherence measures, we compared conflict-related neural activity in the anterior cingulate cortex (ACC) and control-related activity in the lateral frontal cortex (LFC) during Stroop task performance between participants of low and high hypnotic susceptibility, at baseline and after hypnotic induction. The fMRI data revealed that conflict-related ACC activity interacted with hypnosis and hypnotic susceptibility, in that highly susceptible participants displayed increased conflict-related neural activity in the hypnosis condition compared to baseline, as well as with respect to subjects with low susceptibility. Cognitive-control-related LFC activity, on the other hand, did not differ between groups and conditions. These data were complemented by a decrease in functional connectivity (EEG gamma band coherence) between frontal midline and left lateral scalp sites in highly susceptible subjects after hypnosis. These results suggest that individual differences in hypnotic susceptibility are linked with the efficiency of the frontal attention system, and that the hypnotized condition is characterized by a functional dissociation of conflict monitoring and cognitive control processes.
Many studies have suggested that conflict monitoring involves the anterior cingulate cortex (ACC). We previously showed that a specific hypnotic suggestion reduces involuntary conflict and alters information processing in highly hypnotizable individuals. Hypothesizing that such conflict reduction would be associated with decreased ACC activation, we combined neuroimaging methods to provide high temporal and spatial resolution and studied highly and less-hypnotizable participants both with and without a suggestion to interpret visual words as nonsense strings. Functional MRI data revealed that under posthypnotic suggestion, both ACC and visual areas presented reduced activity in highly hypnotizable persons compared with either no-suggestion or less-hypnotizable controls. Scalp electrode recordings in highly hypnotizable subjects also showed reductions in posterior activation under suggestion, indicating visual system alterations. Our findings illuminate how suggestion affects cognitive control by modulating activity in specific brain areas, including early visual modules, and provide a more scientific account relating the neural effects of suggestion to placebo.
• anterior cingulate cortex
• attention
• hypnosis
• neuroimaging
• Stroop effect
The present work was aimed at investigating whether the flanker compatibility effect can be eliminated by means of a posthypnotic suggestion influencing attentional focusing. In Experiment 1, participants who scored high and low on hypnotic susceptibility performed the flanker compatibility task when naturally awake and when under a posthypnotic suggestion aimed at increasing the target's discriminability from the flankers. Results showed that the posthypnotic suggestion effectively eliminated the flanker compatibility effect in highly susceptible participants, whereas low-susceptibility participants did not show any reduction in the effect. In Experiment 2, highly susceptible participants performed the task after receiving a suggestion but without the induction of hypnosis. Results showed that the suggestion alone was not sufficient to reduce the flanker compatibility effect. These results support the view that in highly susceptible participants, hypnotic suggestion can influence the ability to focus on relevant information.
Dissociation: Clinical and Theoretical Perspectives
- E Z Woody
- K S Bowers
Woody EZ and Bowers KS. A frontal assault on dissociated
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Theoretical Perspectives. New York: Guilford, 1994: 52e79.
Hypnotic suggestion reduces conflict in the human brain
- A Raz
- J Fan
- M I Posner
Raz A, Fan J, and Posner MI. Hypnotic suggestion reduces conflict
in the human brain. Proceedings of the National Academy of
Sciences of the United States of America, 102(28): 9978e9983, 2005.