Alcohol increases hypnotic susceptibility

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.     

Multiple predictors of hypnotic susceptibility

In this article, we report two experiments in which various measures thought to be related to hypnotizability were analyzed by stepwise discriminant analysis techniques. Absorption (Tellegen, 1981, 1982; Tellegen & Atkinson, 1974) and preference for an imagic style of thinking (Isaacs, 1982) were robust predictors of hypnotizability; each variable accounted for significant variance in hypnotizability at their respective steps in two samples and correctly classified a significant proportion of low- and high-hypnotizable subjects in the discriminant analyses. The addition of two other variables in Experiment 2--a Sleep-Dream score derived from Evans's (1977) Cognitive Control of Sleep Mentation subscale and Gibson's (1985) Dream Questionnaire, and the Belief in the Supernatural subscale of the Taft (1969) Experience Questionnaire--increased the correct classification of the medium-hypnotizable subjects from chance levels to 74%. It is argued that a confirmatory and hierarchical approach is needed in future studies to explore correlates of hypnotizability more fully.     

Moderating influences of hypnotic susceptibility on signal-detection task performance

This study investigated the differential influence of hypnotic susceptibility level on signal detection task (SDT) performance in waking and hypnotic conditions. As assessed by the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS: A) and the Stanford Hypnotic Susceptibility Scale, Form C (SHSS: C), 20 high (9–12), 20 medium (4–8), and 20 low (0–3) hypnotizables participated. In counterbalanced conditions of waking and hypnosis, Ss (Subjects) were given 36 signal detection trials, consisting of 12 strong signals, 12 weak signals, and 12 “no” signals. No differences were observed in the waking condition between low, medium, and high hypnotizables on strong and weak signal trials. In hypnosis, high hypnotizables exhibited significantly superior performance on the strong signal trials in comparison with low hypotizables, and performed significantly better on the weak signal trials than did the low and medium hypnotizables. Low and medium hypnotizables performed similarly in waking and hypnotic conditions, while high hypnotizables showed significant enhancements in performance for strong and weak signal trials during hypnosis. This research was supported, in part, by a grant from Fort Hays State University.     

Moderating influences of hypnotic susceptibility on signal-detection task performance

This study investigated the differential influence of hypnotic susceptibility level on signal detection task (SDT) performance in waking and hypnotic conditions. As assessed by the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS: A) and the Stanford Hypnotic Susceptibility Scale, Form C (SHSS: C), 20 high (9–12), 20 medium (4–8), and 20 low (0–3) hypnotizables participated. In counterbalanced conditions of waking and hypnosis, Ss (Subjects) were given 36 signal detection trials, consisting of 12 strong signals, 12 weak signals, and 12 “no” signals. No differences were observed in the waking condition between low, medium, and high hypnotizables on strong and weak signal trials. In hypnosis, high hypnotizables exhibited significantly superior performance on the strong signal trials in comparison with low hypotizables, and performed significantly better on the weak signal trials than did the low and medium hypnotizables. Low and medium hypnotizables performed similarly in waking and hypnotic conditions, while high hypnotizables showed significant enhancements in performance for strong and weak signal trials during hypnosis. This research was supported, in part, by a grant from Fort Hays State University.