SOMATIC CONSEQUENCES OF ILLUSIONS
If one goes beyond Cartesian notions, it is evident that, even though we label certain ideas as illusory, they exist in central nervous system tissue and therefore have physiological consequences. No one questions that fantasies and images influence the somatic realm. One only has to consider the commonplace example of how merely thinking about food initiates salivation and gastric mobility. However, despite the obvious connection between fantasy and bodily processes, little attention has been devoted directly to how illusion registers physiologically. True, there have been scattered studies of the impact of illusory ideas implanted by means of hypnosis upon sensory, motor, and autonomic functions (e.g., Kihlstrom, 1985; McGlashan, Evans, & Orne, 1969), and they documented significant effects. Also, various studies have pointed up the potential power of imagination to target specific channels of physiological response (e.g., Cacioppo & Petty, 1983). Becoming anxious about an imagined ("unreal") threat has physiological consequences quite analogous to those evoked by a "real" threat. While it may be apparent that illusory images reverberate in body terms, it is worthwhile to provide some detailed illustrations of such reverberation. Indeed, it can be suggested that ideational paradigms constructed of the illusory stuff of fantasy may shape unique modes of physiological representation.
The best examples of illusion's role in body response come from instances in which individuals are asked to take into their bodies substances to which they falsely ascribe potent properties. Let us begin with a really surprising report by Briddell et al. ( 1978). They were interested in exploring the effects of cognitive and pharmacological factors, linked with alcohol consumption, on sexual arousal to sexual stimuli differing in amount of deviance. Forty-