Earlier studies have shown hypnotizability-related postural effects of visual suppression and of leg and neck proprioceptive alteration. This study completes this investigation by demonstrating the postural effects of asymmetric tactile foot stimulation in standing participants with different hypnotizability scores. During this stimulation, body sway changed in medium-to-high more than in low-to-medium hypnotizable participants. Findings support the view that high hypnotizability is associated with higher vulnerability of posture to sensory alteration; together with earlier results, they suggest a role of the cerebellum in the observed hypnotizability-related differences and prompt investigation of cerebral structures and factors potentially responsible for both the cognitive and physiological aspects of hypnotizability.
The aim of this paper is to complement the recently revised American Psychological Association definition of hypnotizability. It (a) lists a few differences in sensorimotor integration between subjects with high and low hypnotizability scores in the ordinary state of consciousness and in the absence of suggestions; (b) proposes that hypnotizability-related cerebellar peculiarities may account for them; (c) suggests that the cerebellum could also be involved in cognitive aspects of hypnotizability; (d) explains why the information derived from studies of sensorimotor and cardiovascular aspects of hypnotizability may be relevant to its definition and useful in orienting further experimental research in the field of hypnosis.