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)

One approach to hypnosis suggests that for hypnotic experience to occur frontal lobe activity must be attenuated. For example, cold control theory posits that a lack of awareness of intentions is responsible for the experience of involuntariness and/or the subjective reality of hypnotic suggestions. The mid-dorso-lateral prefrontal cortex and the ACC are candidate regions for such awareness. Alcohol impairs frontal lobe executive function. This study examined whether alcohol affects hypnotisability. We administered 0.8 mg/kg of alcohol or a placebo to 32 (...) medium susceptible participants. They were subsequently hypnotised and given hypnotic suggestions. All participants believed they had received some alcohol. Participants in the alcohol condition were more susceptible to hypnotic suggestions than participants in the placebo condition. Impaired frontal lobe activity facilitates hypnotic responding, which supports theories postulating that attenuation of executive function facilitates hypnotic response, and contradicts theories postulating that hypnotic response involves enhanced inhibitory, attentional or other executive function. (shrink)

We examined two potential correlates of hypnotic suggestibility: dissociation and cognitive inhibition. Dissociation is the foundation of two of the major theories of hypnosis and other theories commonly postulate that hypnotic responding is a result of attentional abilities . Participants were administered the Waterloo-Stanford Group Scale of Hypnotic Susceptibility, Form C. Under the guise of an unrelated study, 180 of these participants also completed: a version of the Dissociative Experiences Scale that is normally distributed in non-clinical populations; a latent inhibition (...) task, a spatial negative priming task, and a memory task designed to measure negative priming. The data ruled out even moderate correlations between hypnotic suggestibility and all the measures of dissociation and cognitive inhibition overall, though they also indicated gender differences. The results are a challenge for existing theories of hypnosis. (shrink)

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. (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)

The ‘default mode’ network refers to cortical areas that are active in the absence of goal-directed activity. In previous studies, decreased activity in the ‘default mode’ has always been associated with increased activation in task-relevant areas. We show that the induction of hypnosis can reduce anterior default mode activity during rest without increasing activity in other cortical regions. We assessed brain activation patterns of high and low suggestible people while resting in the fMRI scanner and while engaged in visual tasks, (...) in and out of hypnosis. High suggestible participants in hypnosis showed decreased brain activity in the anterior parts of the default mode circuit. In low suggestible people, hypnotic induction produced no detectable changes in these regions, but instead deactivated areas involved in alertness. The findings indicate that hypnotic induction creates a distinctive and unique pattern of brain activation in highly suggestible subjects. (shrink)

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 , low dissociative highly suggestible , and high dissociative highly suggestible participants completed the Stroop color-naming task in control and hypnosis conditions. The magnitude of conflict adaptation 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. (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)