Auditory hallucinations and the verbal transformation effect: The role of suggestions

Previous studies of the Verbal Transformation Effect (VTE), the tendency to perceive illusory transformations of repeatedly presented words, have yielded conflicting results for hallucinating patients. In the present experiment, the VTE was assessed in hallucinating patients, psychiatric controls and normal subjects under conditions in which it was suggested that different words would be presented and in which no such suggestion was given. No overall differences were observed between the groups for the number of transformations reported or the latencies of transformations. However, hallucinators reported significantly more transformations in the suggestion condition compared to the no suggestion condition. The hallucinators also reported a greater range of transformations. The results indicate that the auditory judgements of hallucinators are highly influenced by beliefs and expectations and that differing VTE results previously obtained from hallucinating patients may reflect the task demands of experiments.