Expectancy factors in the treatment of fear: Methodological and theoretical issues

Critically reviews the literature assessing the importance of Ss' expectation of therapeutic gain in facilitating fear reduction. Reviewed studies fall into 2 major categories: those that compare the relative efficacy of systematic desensitization and placebos and those that attempt to manipulate Ss' expectation of therapeutic gain within a particular technique (e.g., systematic desensitization). The methodological problems with this research include the failure of investigators to evaluate the experiential impact of expectancy-inducing instructions, the use of unconvincing placebo manipulations, and the predominant employment of mildly fearful, poorly motivated Ss. In spite of these problems, it is tentatively concluded that expectancy manipulations are important change mediators. Several mechanisms may explain how expectancy mediates change, including increased compliance with real treatment procedures; increased tendency to test reality after having undergone an "effective" therapy, with subsequent fear extinction and self-reinforcement for behavioral improvement; modification of demand characteristics after treatment; and modification of cognitive events controlling fear responding. (71 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).