Cognitive scientists distinguish between automatic and controlled mental processes. Automatic processes are either innately involuntary or become automatized through extensive practice. For example, reading words is a purportedly automatic process for proficient readers and the Stroop effect is consequently considered the “gold standard” of automated performance. Although the question of whether it is possible to regain control over an automatic process is mostly unasked, we provide compelling data showing that posthypnotic suggestion reduced and even removed Stroop interference in highly hypnotizable (...) individuals. Drawing on a large sample of highly hypnotizable participants, we examined the effects of suggestion on Stroop performance both with and without a posthypnotic suggestion to perceive the input stream as meaningless symbols. We show that suggestion administered to highly hypnotizable persons significantly reduced Stroop interference and derailed a seemingly automatic process. (shrink)

Consciousness alterations can be experienced during unstructured, monotonous stimuli. These effects have not been linked to particular cognitive operations; individual differences in response to such stimulation remain poorly understood. We examined the role of hypnotizability and dissociative tendencies in mind-wandering during a sensory homogenization procedure . We expected that the influence of ganzfeld on MW would be more pronounced among highly hypnotizable individuals , particularly those high in dissociative tendencies. High and low hypnotizables, also stratified by dissociation, completed the (...) sustained attention to response task during ganzfeld and control conditions. High dissociative highs made more commission errors during ganzfeld, suggesting increased MW, whereas the other groups displayed the opposite pattern. Increases in commission errors from the control condition to ganzfeld were associated with more alterations in consciousness and negative affect, but only among highs. Sensory homogenization had opposite effects on MW depending on the interaction of hypnotizability and dissociation. (shrink)

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

Cortex functional connectivity associated with hypnosis was investigated in a single highly hypnotizable subject in a normal baseline condition and under neutral hypnosis during two sessions separated by a year. After the hypnotic induction, but without further suggestions as compared to the baseline condition, all studied parameters of local and remote functional connectivity were significantly changed. The significant differences between hypnosis and the baseline condition were observable (to different extent) in five studied independent frequency bands (delta, theta, alpha, beta, and (...) gamma). The results were consistent and stable after 1 year. Based on these findings we conclude that alteration in functional connectivity of the brain may be regarded as a neuronal correlate of hypnosis (at least in very highly hypnotizable subjects) in which separate cognitive modules and subsystems may be temporarily incapable of communicating with each other normally. (shrink)

The present study investigated how the magnitude the word blindness suggestion effect on Stroop interference depended on hypnotic suggestibility when given as an imaginative suggestion and under conditions in which hypnosis was not mentioned. Hypnotic suggestibility is shown to be a significant predictor of the magnitude of the imaginative word blindness suggestion effect under these conditions. This is therefore the first study to show a linear relationship between the imaginative word blindness suggestion effect and hypnotic suggestibility across the whole (...) class='Hi'>hypnotizability spectrum. The results replicate previous findings showing that highs respond to the word blindness suggestion to a greater extent than lows but extend previous work by showing that the advantage for those higher on the hypnotizability spectrum occurs even in a non-hypnotic context. Negative attitudes about hypnosis may not explain the failure to observe similar effects of the word blindness suggestion in less hypnotizable individuals. (shrink)

Clinical delusions are difficult to investigate in the laboratory because they co-occur with other symptoms and with intellectual impairment. Partly for these reasons, researchers have recently begun to use hypnosis with neurologically intact people in order to model clinical delusions. In this paper we describe striking analogies between the behavior of patients with a clinical delusion of mirrored self misidentification, and the behavior of highly hypnotizable subjects who receive a hypnotic suggestion to see a stranger when they look in the (...) mirror. Based on these analogies, we argue that the use of hypnosis is a reliable method to investigate the surface features of clinical delusions. But to what extent can hypnosis successfully recreate delusions? Can it also contribute to a better understanding of delusion formation? Although clinical delusions and hypnotically induced beliefs are different in etiology, some analogies can be identified in the underlying processes that characterise them, based on the two-factor theory of delusion formation. (shrink)

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

The purpose of our study was to measure the relationship between performance on various attentional tasks and hypnotic susceptibility. Healthy volunteers participated in a study, where they had to perform several tasks measuring various attention components in a waking state: sustained attention, selective or focused attention, divided attention and executive attention in task switching. Hypnotic susceptibility was measured in a separate setting by the Waterloo-Stanford Groups Scale of Hypnotic Susceptibility, Form C .We found no significant correlation between any of the (...) attentional measures and hypnotic susceptibility. Highly hypnotizables did not prove to be superior to or worse than the other individuals in any of the tests.These results do not support the neuropsychophysiological model of hypnosis, as they show no consistent relationship between hypnotic susceptibility and waking attentional performance. (shrink)

Research by Raz and his associates has repeatedly found that suggestions for hypnotic agnosia, administered to highly hypnotizable subjects, reduce or even eliminate Stroop interference. The present paper sought unsuccessfully to extend these findings to negative priming in the Stroop task. Nevertheless, the reduction of Stroop interference has broad theoretical implications, both for our understanding of automaticity and for the prospect of de-automatizing cognition in meditation and other altered states of consciousness.

The demonstration that hypnotic suggestion can inhibit word/colour Stroop highlights one of the benefits of using hypnosis to explore cognitive psychology and in particular attentional processes. The compelling results using a rigorous design have particular relevance for the presumed automaticity of some forms of information processing. Moreover the results support the potential that hypnotic suggestion offers for creating clinically informed analogues of relevant psychological and neuropsychological conditions. As with all novel research, the results of Raz and Campbell raise further operational (...) and theoretical questions, relating in this case to the use of hypnotic, post-hypnotic and non-hypnotic suggestion and the utility of existing measures of hypnotizability. (shrink)

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 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. (shrink)

“Altered State of Consciousness” (ASC) has been defined as a changed overall pattern of conscious experience, or as the subjective feeling and explicit recognition that one's own subjective experience has changed. We argue that these traditional definitions fail to draw a clear line between altered and normal states of consciousness (NSC). We outline a new definition of ASC and argue that the proper way to understand the concept of ASC is to regard it as a representational notion: the alteration that (...) has happened is not an alteration of consciousness (or subjective experience) per se, but an alteration in the informational or representational relationships between consciousness and the world. An altered state of consciousness is defined as a state in which the neurocognitive background mechanisms of consciousness have an increased tendency to produce misrepresentations such as hallucinations, delusions, and memory distortions. Paradigm examples of such generally misrepresentational, temporary, and reversible states are dreaming, psychotic episodes, psychedelic drug experiences, some epileptic seizures, and hypnosis in highly hypnotizable subjects. The representational definition of ASC should be applied in the theoretical and empirical studies of ASCs to unify and clarify the conceptual basis of ASC research. (shrink)

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 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. (shrink)

Two experiments investigated the reality attributed to hypnotic suggestion through subtle projection of a visual image during simultaneous suggestion for a visual hallucination that resembled the projected image. In Experiment 1, high and low hypnotizable participants were administered either a hypnotic induction or wake instructions, given a suggestion to hallucinate a shape, and then the projected image was subsequently introduced. Although highs in both conditions rated the projected image more vividly than lows, highs in the hypnosis condition made comparable reality (...) ratings when the projected image was absent and present. In Experiment 2, high hypnotizable participants were administered a suggestion to see a shape on a wall. For half the participants the suggested image was projected on the wall and then removed, and for half the projection was initially absent and then introduced. Participants who had the projection absent and then present reported comparable reality and vividness ratings when the projection was absent and present. These findings indicate that elevated hypnotizability and hypnosis are associated with attributions of external reality to suggested experiences. (shrink)

The target article's use of core concepts is confused and excessively broad. Two main types of experiences have been described in relation to shamanism: magical flight and mediumship/possession. The first refers to visual and remembered experiences of events in other realms, the second to embodied experiences of ceding mental control and personality to a preternatural entity. These experiences grossly correspond to two main experience modalities exhibited by highly hypnotizable individuals in a secular setting.

The present study examined the trait-like nature of hypnotic suggestibility by examining the stability of hypnotic responsiveness in a test–retest design in which the procedures were administered either live or by audiotape. Contrary to the idea that hypnotizability is a largely immutable, stable trait, scores on the scale of hypnotic responsiveness decreased significantly at the second session. Measures of subjective experiences and expectancies accounted for a sizable portion of the variance in hypnotic responding, both at initial test and at (...) retest. Participants became disengaged with the hypnotic procedures at retest. Participants who received the hypnotic induction by audiotape did not differ from participants who received it live. The results are consistent with sociocognitive and altered state theories of hypnosis, and underline the important role of subjective experiences in hypnotic responding. (shrink)

In the present article we consider general anesthesia as a means of exploring questions regarding unconscious influence. The primary questions addressed in the research are whether surgical patients who are under adequate general anesthesia unconsciously perceive auditory information and whether they can benefit from such information. In addition, we consider the relevance of individual hypnotic ability for perceptual processing in this context. Ninety-six adult patients, undergoing elective abdominal hysterectomy, were randomly allocated to one of four tape-recorded conditions: therapeutic suggestions, melodies, (...) suggestions-plus-melodies, or silence. Double-blind conditions were satisfied in every respect. Patients received a standardized, but typical, "balanced" anesthetic, and level of anesthesia was adequately monitored. Following surgery, all patients received their analgesic medication from a patient-controlled device. Patients who were played therapeutic suggestions used a significantly smaller dose of morphine than patients who were not played suggestions. Although hypnotic ability was not significantly associated with therapeutic outcome, high but not low hypnotizable patients accurately guessed whether they were played suggestions. No compelling evidence for memory of melodies was obtained. (shrink)