The psychophysics of cold pressor pain and its modification through hypnotic suggestion.

Abstract

Earlier reports of the pain of putting hand and forearm in circulating ice water were recomputed to study how subjects scale that pain and to find appropriate measures of its reduction under hypnotic analgesia. The numerical scaling (0 to 10, open at the top) tended to follow a power function with time (5-sec intervals from immersion), sometimes requiring a new exponent at high reported values. Changes in water temperature led to power functions differing in slope, while hypnotic analgesia and hallucinated pain led instead to power functions differing primarily in intercept value. Hypnotic analgesia, then, acted as a 'filter' between stimulus and response, and was best measured by ratio scores when comparing responses by separate groups of subjects. The cold pressor response has been widely used in the laboratory investigation of pain ever since its introduction by Hines and Brown (1932). Interest has commonly centered on vasomotor or other physiological correlates, but there have all along been some studies in which the verbal responses to pain have been given careful quantitative study (e.g., Wolf and Hardy, 1941). The present report uses data from several previous experiments, in which physiological measures (heart rate, blood pressure) were also recorded, but it concentrates on a new analysis of the verbal responses to cold pressor pain as a function of time in the water, of water temperature, and of hypnotic suggestion, and on some effects of attempts to anchor the scale in order to lead to more uniform reporting from subject to subject.