Hypnosis - Hallucinations

A hallucination is defined as a perception in the absence of a real external stimulus. Usually the occurrence of a hallucination is a symptom of a psychotic disorder, but under certain circumstances, normal people may hallucinate. These situations include conditions of sensory deprivation, extreme hunger or thirst, fever, drugs, REM sleep (nocturnal dreams), and, in some cases, scrying (crystal ball gazing). Normal people may also hallucinate under the influence of suggestions, hypnotic or otherwise.

Psychotic hallucinations in general have both a characteristic sensory mo dality and a characteristic content that vary between diagnostic categories. For example, schizophrenic hallucinations are predominantly auditory and have a characteristic obscene or self-critical content. Most psychotic hallucinations are accompanied by a delusional belief in their objective reality that is often absent in the hallucinations of normal people. This phenomenon is not intrinsically unreasonable, for psychotic hallucinations tend to be consis tent with past experience. For example, a hallucinated image will usually ob scure parts of real images lying in back of it in the visual field, and it will cast a reflection in a mirror. All of his life the patient has been correct in believing the information his sense organs have communicated to him about the ex­ternal world, and there is no reason why he should not believe in the ver-idicality of these images when they are hallucinated.

In the case of the hypnotically suggested hallucination, the modality and the contect of the hallucination are functions of the suggestions made. Hallucinations can be suggested in any sense modality; the ones most commonly used are vision, audition, olfaction, gustation, touch, heat, and cold. : hallucinations may be suggested in specific modalities or it may produce multimodality effects. For example, the hallucinated fly in the Stanford test (SHSS:A) may produce visual, auditory, fects. In addition to positive hallucinations, negative hal-the subject fails to perceive some real external stimulus, ted. These are analogous, if not identical, to the everyday >erson is looking directly at an object that he is searching :e it. Those portions of the external environment that are lotic suggestions are generally perceived accurately if not (Orne, 1962d).

Hallucinations in general are difficult to elicit under hypnosis, and there is ilty between the various sensory modalities. Tactile hallucinations are comparatively easy to produce. Suggesting to a group of nons that they should notice that their noses are beginning to in effect in many of them. So will reading a paragraph iing that might be used in making such a suggestion. The rises of olfaction and gustation are also more amenable to ! more highly developed senses of audition and vision.

Orne (1962d) points out that when a visual hallucination is suggested In a subject he may react in a variety of ways. He may act as though he sees 1 what has been suggested or seem disturbed because he does not experience it. In the former case, if he is questioned after the experience, he may say that (1) he saw nothing but felt compelled to act as if he did; (2) he expeFrienced a visual image but knew it was unreal; (3) he experienced a real external image but it had illogical aspects to it (e.g., he could see a chair j through a hallucinated person); or (4) he experienced an image indistinguish able from reality. Thus Orne categorized the subject's subjective experience into one of four categories. He considers only the last two as true halluci nations. In actuality, there is probably an infinite series of gradations of subject responses, and individual investigators differ in what they define as a positive | response to a suggested hallucination.

Another point needs to be made: there is no way for an experimenter to observe the subject's hallucination directly. Hence he or she must rely on the subject's verbal report of his or her experiences. Thus it is possible, and in deed probable, that one subject who experiences a hallucination more vividly than another may report it as less vivid because of individual differences in the use of language and subjective standards of what the term vivid means. This is the same problem experienced by dream researchers who purport to be studying dreams but are actually studying verbal reports of dreams. The only hallucinations that an investigator can observe directly are his or her own, and these are necessarily individual and atypical. The question about the relative subjective experiences of two different subjects reporting their own hallucinations, no matter how similar or different their verbal descriptions, is as unanswerable by observation as is the question of whether two subjects describing the same stimulus as blue are having the same or radically different subjective experiences.

Such questions are philosophical, not scientific, ones. Although the degree of the apparent reality of a hallucination can only be estimated by a verbal report, Orne (1962d) attempts to distinguish effects that are actually experienced from those that are simulated by subjects motivated to produce what the experimenter wants them to by the use of stimulating subjects. These are subjects who have not been hypnotized but have been instructed to act as if they have been and to attempt to deceive the experi menter making the behavioral observations (who is not told which subjects are actually hypnotized). Simulators are usually informed that if the experi menter discovers that they are simulating, he or she will halt the procedure; hence, its continuation lets the simulator know he is successful in efforts at deception. The logic behind the use of simulating subjects is that both hyp notized subjects and simulators are equally motivated to produce the sug gested behavior, but if only the hypnotic subjects actually experience the ef fects suggested, their behavior may be different to some degree from that of the subjects who are faking an effect. The lack of knowledge on the part of the experimenter of the real or simulating status of a subject eliminates experimenter bias and prevents any unconscious systematic differential treatment of the two types of subjects.

There are behavioral differences between real subjects and simulators. If a subject is told to hallucinate the experimenter sitting in a chair and is then told to turn around and look at where the experimenter really is, he will often appear surprised and report seeing him twice. He may not know which image is real. (Some subjects will distinguish the real from the hallucinated image by having the hallucinated one raise his hand.) Simulating subjects will usually deny seeing the experimenter when looking at him because they believe they are not supposed to.

If a negative hallucination is suggested so that the subject is told he can no longer see a chair and then is asked to walk in a direct line with the chair, hypnotized subjects will avoid bumping into the chair, while simulators will Usually walk into it. Spanos, Churchill, and McPeake (1976) found that a cooperative attitude toward hypnosis and involvement in everyday fantasy were each positively correlated with the ability of a subject to experience visual and auditory hal lucinations. Visual hallucinations were more difficult to produce than auditory hallucinations, but they found that the abilities to produce these two types of hallucinations were correlated. They reported no sex difference in the ability to hallucinate. A large majority of their subjects reported their experiences as Imagined rather than seen or heard. Ham and Spanos (1974) report that with 60 male and female subjects equally assigned to hypnotic and task-motivational groups, the task-moti vated subjects performed better in response to suggestions of visual or au-ditory hallucination. Spanos, Mullens, and Rivers (1979) in a 2 x 3 factorial study compared hypnotic and task-motivated subjects in performance of vis ual and auditory hallucinations in response to brief suggestions, long sug gestions, and suggestions providing an imaginary context. Task-motivated subjects performed better than hypnotic subjects on auditory hallucinations, I and the authors report a "trend toward significance" in this direction on visual hallucinations. Both long and image-involving suggestions were equally more effective than short suggestions for auditory hallucinations but were not sig nificantly different for visual hallucinations.