Hypnotizability and imagery modality preference: Do highs and lows live in the same world?

Imagery is considered largely involved in hypnotic phenomena. Recent findings have shown, however, that not hypnotized subjects with high (Highs) and low (Lows) susceptibility to hypnosis undergoing guided imagery tasks centred on specific sensory modalities share a similar visual imagery ability. In contrast, Highs obtain a better imagery than Lows when tactile instructions are given. Aim of the experiment was to confirm this finding using instructions of globally reduced perception instead of suggestions centred on specific sensory modalities, assuming that the preferred imagery modality would be the least easily suppressed. The changes in body sway (that are sensitive to cognitive activity because postural control requires attention) were used as indexes of possible different cognitive load of the task in Highs and Lows. The results confirmed the hypothesis that Highs and Lows differ in their preferred imagery modalities and showed that Highs’ body sway was not modified by the simultaneous imagery of globally reduced perception, while Lows increased their sway while perceiving a decreased sensory availability. The Discussion is focussed on the similar networks involved in imagery and perception and on the possible differences between Highs and Lows in the mechanisms of imagery/perception and sensory-motor integration.