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2. What is a hypnotic "trance" ?

2.7. Evidence of enhanced functioning following suggestion?

Some of the 'unusual capacities' often claimed of hypnosis are actually legitimate, but found to be quite normal capacities seen in various non-hypnotic situations as well, though the hypnotic 'deep trance' context does apparently give a unique kind of access to those normal capacities. Seemingly a product of the unique sort of attention control found in hypnotic responding.

"Trance permits the operator to evoke in a controlled manner the same mental mechanisms that are operative spontaneously in everyday life."

Milton Erickson

T.X. Barber, a highly respected researcher into human functioning under hypnosis has long promoted the view that people can bring out their own inner capabilities by direct requests to think, feel, and experience in a suggested way, without any need for hypnotic induction. He says that the secret of hypnosis involves the ability to fantasize in a hallucinatory way and provide the drama and excitement. Also important, according to Barber, is the way in which suggestions are given, language which gives firm but metaphorical suggestions.

Keith Harary, in his March/April 1992 Psychology Today article, "The trouble with HYPNOSIS. Whose power is it, anyway?" reviews a number of critical studies of hypnosis and concludes a similar view:

"Packaging them [the true claims made about hypnosis] under the label 'hypnosis' conceals what is really going on. It doesn't even begin to suggest that they are our very own powers and there might be ways to get at them directly and entirely on our own."


2.7.1. 'Mind and Body' in medicine

We see that there is little of any consistency that can be said about light trance objectively, and possibly only 'trance logic' (if that) as a common characteristic of deep trance. Yet the subjective experience of the individual is sometimes very profoundly altered.

And some phenomena can be reliably reproduced in good subjects which are medically considered very unusual and hard to explain (though not necessarily limited to hypnosis situations). The working medical framework that had traditionally cleanly separated psychogenic from physiological effects has been revised in parts to allow for some of the mechanisms related to effects found in good hypnotic subjects; such as influences between neural and immunological systems, dermatological (skin) responses that were previously believed not to be able to be influenced by the brain and nervous system, and the difficult but demonstrable 'biofeedback' ability to indirectly control very small neural units previously considered completely autonomic.

In terms of the prevailing medical paradigm, numerous functional interconnections within the brain and between the nervous system and other body systems have been found that may gradually help to explain such remarkable effects as we see in hypnosis and under various other seemingly special psychological conditions. Among other key discoveries, the study of neuropeptides and their distribution throughout the body as well as the brain provides some potential answers for some of the more perplexing questions arising from effects due to suggestion.

Richard Benson's "relaxation response" research pioneered in this area, and a great many studies since then have validated his ideas about psychological and physiological functions greatly influencing each other. Two recent article that are fairly typical are in the June 1989 issue of the mainstream medical specialty journal Gastroenterology, "Hypnosis and the relaxation response" and "Modulation of gastric acid secretion by hypnosis."

An excellent review of the research into the exact physiological effects found to result from hypnotic suggestions in particular may be found in these two of T.X. Barber's articles ...

  • "Physiological effects of 'hypnosis,' Psychological Bulletin, 58: 390-419, 1961
  • "Physiological effects of 'hypnotic suggestions': a critical review of recent research (1960-1964)," Psychological Bulletin, 63: 201-222, 1965.

In addition to these general references, the following sections may help to follow-up on any interest into various specific apparent unusual effects of suggestion.


2.7.2. Hypermnesia, perceptual distortions, hallucinations

Hypermnesia is perceived enhanced recall of memories. See also the later section on the reliability of hypnotic recall.

An excellent overview of experimental and clinical studies of hypermnesia, perceptual distortions, and hallucinations under hypnosis may be found in the hypnosis section of the Annual Review of Psychology, especially these issues spanning 20 years of research into hypnotic phenomena:

  • Vol 16, 1965, E. Hilgard, p. 157-180
  • Vol 26, 1975, E. Hilgard, p. 19-44
  • Vol 36, 1985, J.R. Kihlstrom, p. 385-418

Another related area is the remarkable phenomena of eidetic imagery, or 'photographic memory.' In recent years, this formerly controversial phenomenon has been demonstrated by means of computer generated random pixel patterns which stereoscopically encode a visual image. There would be two images which, one seen by each eye at the same time, produce a three dimensional visual image. It is considered virtually impossible to detect the encoded image by looking at the separate encoded patterns at different times. People with eidetic imagery can memorize one pattern, and then mentally project it with one eye while looking at the other pattern with the other eye. The result is that they can see the three dimensional image, while apparently no amount of motivation will permit someone without eidetic imagery to see the final image.

It is now known that many five year old children can experience eidetic imagery, and that it is very rare in adults. A study published in the Journal of Abnormal Psychology in 1975 (and a follow-up three years later) demonstrated that the rate of eidetic imagery in adults hypnotically regressed to age five was comparable to that in actual five year olds.

This could be interpreted as evidence of true temporal regression in hypnosis in some sense, although that interpretation seems unlikely in the face of evidence in other areas. It is more likely to provide unique evidence of state-specific abilities accessible through hypnotic suggestion.

The following are the studies quoted above:

  • Walker, Garrett, & Wallace, 1976, "Restoration of Eidetic Imagery via Hypnotic Age Regression: A Preliminary Report," Journal of Abnormal Psychology, 85, 335-337.
  • Wallace, 1978, "Restoration of Eidetic Imagery via Hypnotic Age Regression: More Evidence," Journal of Abnormal Psychology, 87, 673-675.

In addition, Michael Nash in his chapter "Hypnosis as Psychological Regression," in Lynn and Rhue's 1991 Theories of Hypnosis discusses the evidence around different kinds of psychological regression and also refers to an unpublished manuscript by Crawford, Wallace, Katsuhiko, and Slater, from 1985, which is said to also discuss positive evidence for the facilitation of eidetic imagery phenomenon with hypnotic techniques: "Eidetic Images in Hypnosis, Rare but There."


2.7.3. Posthypnotic suggestion and amnesia

Amnesia (basically selective forgetting in this case) sometimes occurs spontaneously in hypnosis, and sometimes happens as the result of a direct or indirect suggestion to forget something. The amnesia effect may last a variable time, possibly months or longer, depending on the psychological significance of the amnesia and the forgotten material and on the intensity of attempts to recall and availability of recall cues in the environment.

A posthypnotic suggestion in general is a response to hypnotic suggestion that extends beyond the boundary of the actual trance period. Posthypnotic suggestions are often performed without any knowledge that they were previously suggested (thus the necessary link to hypnotic amnesia of this phenomena). The individual responding to a posthypnotic suggestion and with amnesia for the source of the suggestion will generally incorporate the response into their ongoing activities without disruption, in a similar manner to ritualized actions that we pay little attention to such as brushing our teeth in the morning or making the right sequence of turns in our well established route to work each morning. If the response involves some bizarre action, the individual will either be confused or typically will come up with a creative rationalization for the behavior. Very rarely will there be any awareness of the action resulting from a previous suggestion.

It is the contention of many experts in hypnotic work that individuals can and do resist posthypnotic suggestions that they do not wish to perform, except that implicit trust of the hypnotist may promote a behavior out of the ordinary. This is sometimes (especially per Orne) considered more a factor of the relationship between the hypnotist and subject than a matter of any capacity to use hypnosis to coerce a person without their knowledge. The later section on hypnosis and volition will cover this in grater detail.

See the following sources of information on post-hypnotic research, in addition to the Hilgard article in Vol. 16 of Annual Reviews (1965), cited above:

  • W. Wells, 1940, "The extent and duration of post-hypnotic amnesia," Journal of Psychology, 9:137-151.
  • Edwards, 1963, "Duration of post-hypnotic effect," British Journal of Psychiatry, 109: 259-266.
  • Dixon, 1981, "Preconscious Processing" (book)

Various studies have also been done to try to determine what kinds of psychological pressure will cause hypnotic amnesia to be breached, and under what conditions.

Schuyler & Coe, "A physiological investigation of volitional and nonvolitional experience during posthypnotic amnesia," Journal of Personality & Social Psychology, 40(6):1160-9, 1981 Jun was a good example.

Highly responsive hypnotic subjects, who were classified as having control over remembering (voluntaries) or not having control over remembering (involuntaries) during posthypnotic amnesia, were compared with each other on four physiological measures (heart rate, electrodermal response, respiration rate, muscle tension) during posthypnotic recall. Two contextual conditions were employed: One was meant to create pressure to breach posthypnotic amnesia (lie detector instructions); the other, a relax condition, served as a control. The recall data confirmed earlier findings of Howard and Coe and showed that voluntary subjects under the lie detector condition recalled more than the other three samples that did not differ from each other. However, using another measure of voluntariness showed that both voluntary and involuntary subjects breached under lie detector conditions. Electrodermal response supported the subjects' reports of control in this case. Physiological measures were otherwise insignificant. The results are discussed as they relate to (a) studies attempting to breach posthypnotic amnesia, (b) the voluntary/involuntary classification of subjects, and (c) theories of hypnosis.


2.7.4. Pain control (analgesia and anesthesia)

Hypnosis was at one time frequently and successfully used for surgical anesthesia. It is still sometimes used effectively for dental work, childbirth, and chronic pain of various types. Pain control is one of the most reliable and most studied of the hypnotic phenomena.

n addition to Hilgard's article in Vol 26 of Annual Reviews (1975) see:

  • Hilgard, Hilgard, Macdonald, Morgan, and Johnson, 1978, "The reality of hypnotic analgesia: a comparison of highly hypnotizables with simulators." The authors find that motivated simulation of hypnotic analgesia is easily distinguished from hypnotic analgesia.
  • Hilgard and Hilgard, 1983, "Hypnosis in the relief of pain" (book)
  • In 'Evaluation of the efficacy and neural mechanism of a hypnotic analgesia procedure in experimental and clinical dental pain,' 4,41-48, Pain, 1977, J. Barber and D. Mayer reported that effective analgesia was produced by a refinement of hypnotic technique, and was not reduced by naloxone. J. Barber, neuropsychiatry at UCLA, seems to have somewhat specialized in this area.
  • Another 1977 study, Stern, Brown, Ulett, and Sletten, 'A comparison of hypnosis, acupuncture, morphine, Valium, aspirin, and placebo in the management of experimentally induced pain,' Annals of the New York Academy of Sciences, 296, 175-193, found that acupuncture, morphine, and hypnotic analgesia all produced significantly reduced pain ratings for cold pressor and ischemic pain.
  • Van Gorp, Meyer, and Dunbar, 'The efficacy of direct versus indirect hypnotic induction techniques on reduction of experimental pain,' International Journal of Clinical and Experimental Hypnosis, 33, 319-328, 1985 (with cold pressor pain).
  • Tripp and Marks, 1986, compared hypnosis and relaxation with regard to analgesia for cold pressor pain in 'Hypnosis, relaxation, and analgesia suggestions for the reduction of reported pain in high- and low-suggestible subjects,' Austrailian Journal of Clinical and Experimental Hypnosis, 33, 319-328.
  • H.B. Crasilneck et al., 1955, "Use of hypnosis in the management of patients with burns," Journal of the American Medical Association, 158: 103-106.
  • D. Turk, D.H. Meichenbaum, and M. Genest, (1983), Pain and behavioral medicine: a cognitive-behavioral perspective, New York: Guilford Press has a review of cognitive-behavioral strategies for pain control in general, not limited to hypnosis.
  • In Larbig W. Elbert T. Lutzenberger W. Rockstroh B. Schnerr G. Birbaumer N. EEG and slow brain potentials during anticipation and control of painful stimulation. Electroencephalography & Clinical Neurophysiology. 53(3):298 -309, 1982 Mar., EEG corrrelates of pain control were studied.

Cerebral responses in anticipation of painful stimulation and while coping with it were investigated in a "fakir" and 12 male volunteers. Experiment 1 consisted of 3 periods of 40 trials each. During period 1, subjects heart one of two acoustic warning stimuli of 6 sec duration signaling that either an aversive noise or a neutral tone would be presented at S1 offset. During period 2, subjects were asked to use any technique for coping with pain that they had ever found to be successful. During period 3, the neutral S2 was presented simultaneously with a weak electric shock and the aversive noise was presented simultaneously with a strong, painful shock. EEG activity within the theta band increased in anticipation of aversive events. Theta peak was most prominent in the fakir's EEG. A negative slow potential shift during the S1-82 interval was generally more pronounced in anticipation of the aversive events that the neutral ones, even though no overt motor response was required. Negativity tended to increase across the three periods, opposite to the usually observed diminution. In Experiment 2, all subjects self- administered 21 strong shock-noise presentations. The fakir again showed more theta power and more pronounced EEG negativity after stimulus delivery compared with control subjects. Contrary to the controls, self-administration of shocks evoked a larger skin conductance response in the fakir than warned external application.


2.7.5. Dermatological responses

Some of the most interesting hypnotic phenomena involve the apparent precision production of subtle skin responses by suggestion. Allergic reactions, pseudo-sunburns, blisters, and weals have been produced by suggestion. In addition, it has long been known that certain highly troublesome skin conditions have been influenced or healed in some people by suggestion (with or without hypnotic induction).

See the following for further information on studies of this:

  • Ullman & Dudek, 1960, "On the psyche and warts: II. Hypnotic suggestion and warts," Psychosomatic Medicine, 22:68-76
  • Rulison, 1942, "Warts, A statistical study of nine hundred and twenty one cases," Archives of Dermatology and Syphilology, 46:66-81.
  • Asher, 1956, "Respectable Hypnosis," British Medical Journal, 1: 309-312
  • R.F.Q. Johnson and T.X. Barber, 1976, "Hypnotic suggestions for blister formation: Subjective and physiological effects," American Journal of Clinical Hypnosis, 18: 172-181.
  • Mason, 1955, "Icthyosis and hypnosis," British Medical Journal, 2: 57-58.
  • M. Ullman, 1947, "Herpes Simplex and second degree burn induced under hypnosis, American Journal of Psychiatry, 103: 828-830.


2.7.6. Control of bleeding

Experiments with hypnosis during surgery have found that suggestion during and after surgery can reduce bleeding significantly, as well as help with the management of pain.

See Clawson and Swade, 1975, "The hypnotic control of blood flow and pain: The cure of warts and the potential for the use of hypnosis in the treatment of cancer," American Journal of Clinical Hypnosis, 17: 160-169.


2.7.7. Cognition and learning

This is a broad area covering a number of factors that are difficult to separate. In addition to the critical review by Barber in 1965 cited above in (1), see G.S. Blum, 1968. "Effects of hypnotically controlled strength of registration vs. rehearsal," Psychonomic Science", 10: 351-352, which discusses hypnosis as a possible way of reducing rehearsal needed to learn something new.

In some of his publications, researcher Charles Tart discusses the concept of state-specific abilities, including the possibility that some might apply to hypnotic phenomena. See his States of Consciousness, and other related works for more on this.


2.7.8. Enhanced strength or dexterity

The effect of hypnotic suggestion in apparently enhancing physical performance under certain conditions seems to relate to the unusual control over focus of attention available in hypnosis, which permits improved concentration and increased motivation in some athletes, and can be used to modify or lessen the influence of inhibiting beliefs or attitudes. Similar effects are seen when athletes are motivated in other ways, outside of hypnosis.

See T.X. Barber's 1966 paper, "The effects of 'hypnosis' and motivational suggestion on strength and endurance: a critical review of research studies," British Journal of Social and Clinical Psychology", 5:42-50.


2.7.9. Immune Response

It has long been supposed (and in recent years demonstrated experimentally) that emotions and psychological state somehow have an effect on human immune response, but even though detailed mechanisms and the limits of this effect have not been well understood in modern medical science. A recent article in Science News, Sept. 4,1993, pp. 153, describes 'the first solid evidence that hypnosis can modify the immune system far more than relaxation alone."

The report concerns the research of Patricia Ruzyla-Smith of Washington State University in Pullman and her co-workers, who conclude that "hypnosis strengthens the disease-fighting capacity of two types of immune cells, particularly among people who enter a hypnotic trance easily."

This appears to correspond well with and bolster the previous findings related to enhanced 'placebo' (psychosomatic) effects in good hypnotic subjects, in the hypnotic induction situation. However, it does not appear to address the persistent question of whether highly hypnotizable subjects have a unique capacity for psychosomatic regulation, or whether they simply exhibit this capacity common to all of us in a uniquely accessible and convenient way by responding to hypnotic suggestion.

In this research, the psychologists recruited 33 college students who achieved a hypnotic trance easily and 32 students who had great difficulty doing so. Volunteers viewed a brief video describing the immune system and then were assigned to one of three groups: hypnosis, in which they listened to a hypnotic induction asking them to imagine their white blood cells attacking "germ cells" in their body and then performed this exercise through self-hypnosis twice daily for one week; relaxation, in which they floated effortlessly in a large tank of warm water containing Epsom salts and repeated the session one week later; or neither method.

Students who underwent hypnosis displayed larger jumps in two important classes of white blood cells than participants in the other groups. The greatest immune enhancement occurred among highly hypnotizable students in the hypnosis group.


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