Heart rate biofeedback and cold pressor pain: effects of expectancy.

The study investigated the effects of expectancy on the reduction of cold pressor test pain using heart rate biofeedback training. Thirty-six male subjects were given an initial 45-sec cold pressor test, 25 heart rate decrease feedback training trials, and a final cold pressor test in which they were told to decrease their heart rate, but without the aid of feedback. Two levels of outcome expectancy (increase pain, decrease pain) and two levels of cold pressor water temperature (0 degrees C, 5 degrees C), resulting in four groups (N = 9 per group), were used to assess the interaction between expectancy and aversive stimulus intensity. Immediately prior to the final cold pressor test, the increase pain expectancy subjects were told that decreasing their heart rate during the ice water immersion would cause more pain. Decrease pain subjects were told that decreasing their heart rate would cause less pain. Expectancy was found to be the major determinant of pain reports. The decrease pain subjects consistently reported less pain on the final cold pressor, whereas the increase pain subjects consistently reported more pain. Contrary to prediction, expectancy effects were greater for the colder water. The findings indicate the importance of expectancy in the clinical use of biofeedback to control pain.