Hypnotic Hallucinations as “Unmonitored” Images: An Empirical Study

In studying waking images and hypnotic hallucinations, most psychologists have implicitly adopted Hume's sensory continuum theory: that perceived sensations and imaged sensations differ only inasmuch as the latter tend to be less vivid. The current research contrasts sensory continuum theory with an alternative theory: that the central innervation of waking images, especially vivid images, is neurally monitored and tacitly known. To the extent that vivid images demand a greater amount of central innervation, the image-monitoring process should register them more quickly than faint images, even though vivid images are closer to percepts on the sensory continuum. Consistent with image-monitoring theory and contrary to sensory continuum theory, waking subjects discriminated percepts more quickly from vivid images than from faint images. In contrast, deeply hypnotized subjects did not discriminate percepts most quickly from vivid images. The latter result suggests that deep hypnosis attenuates the monitoring process and, thereby, turns “centrally innervated” images into “unmonitored” hallucinations – the most vivid of which tend to be least distinguishable from hypnotic percepts.