Experimental designs, expectancy effects, and hypnotic analgesia.

40 undergraduates who scored high on the Harvard Group Scale of Hypnotic Susceptibility were randomly assigned to 1 of 4 groups. Each group received 3 60-sec immersions of cold-pressor pain stimulation. Immersions were associated with either hypnotic, waking, or no analgesia (control) instructions. The treatments and their order were varied across groups to induce different expectations about the efficacy of hypnotic and waking analgesia. Magnitude estimates and category scale ratings of pain indicated that hypnotic analgesia was more, less, or equally as effective as waking analgesia, depending on the expectations induced by varying treatment order. Pain ratings were also related to the type of cognitive activity (e.g., imaginative coping) engaged in during an immersion. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)