This investigation was designed to determine the extent to which contextual cues mediated the effectiveness of systematic desensitization and a plausible placebo in alleviating public speaking anxiety. After participating in a public speaking situation that allowed the collection of self-report, physiological, and behavioral manifestations of anxiety, 67 subjects were randomly assigned to receive five sessions of either desensitization, "T scope" therapy, or no treatment. Each of these conditions was conducted in a context that either stressed the clinical relevance of the procedure or presented the procedure as a laboratory investigation of fear without therapeutic implications. Analysis of changes both between groups and within individuals indicated that desensitization reduced public speaking anxiety in both contexts, whereas the placebo was effective only in the therapeutic setting. The superiority of desensitization was most pronounced on the physiological variables. The results are interpreted as indicating support for a counterconditioning, rather than an expectancy, interpretation of desensitization.

No abstract