SENSORY-DECISION THEORY ANALYSIS OF PLACEBO EFFECT ON CRITERION FOR PAIN AND THERMAL SENSITIVITY (D')

Administration of a placebo described as a potent analgesic to 22 normal paid volunteers sharply decreased the proportion of pain responses to radiant heat stimulation, suggesting that the threshold for pain had been raised. However, analysis of the data by sensory-decision theory demonstrated that thermal sensitivity remained unchanged. The effect of the placebo was solely to alter Ss' response bias or likelihood ratio criterion (p < .005). (36 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.