Autonomic responses to suggestions for cold and warmth in hypnosis

The goal of the present study was to investigate whether suggestions for cold or warmth during hypnosis affect fingertip skin temperature. Hypnosis without specific suggestions for cold or warmth ('neutral hypnosis') caused a drop in respiration frequency, however, pulse rate, fingertip skin temperature, and electrodermal activity were not affected. The cold and warmth suggestions decreased and increased fingertip skin temperature, respectively. Compared with the neutral trance phase, the other three autonomic variables measured were also affected by suggestions for cold. However, there was no association between the changes in autonomic variables induced by suggestions and hypnotizability scores measured by the 'Stanford Hypnotic Clinical Scale for Adults'. Fingertip skin temperature was mostly affected when the images used for the cold and warmth suggestions during hypnosis included experiences of physical temperature and psychological stress or relaxation, indicating that the psychological content of the imagery amplified the autonomic response.