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Definition: hypnosis from Philip's Encyclopedia

State of relaxation and suggestibility brought about by interaction between a hypnotist and a subject. The exact nature of hypnosis is unclear. Hypnosis is put to many uses, from stage entertainment to treatment for pain and addiction, and it is sometimes used in psychoanalysis.

Summary Article: Hypnosis
From The Corsini Encyclopedia of Psychology and Behavioral Science

From the time of Mesmer, hypnosis has captured the attention of luminaries in psychology including Sigmund Freud, Alfred Binet, William James, Wilhelm Wundt, Clark Hull, and Ernest R. Hilgard. Today, hypnosis is well positioned within the mainstream of psychology. Researchers have debunked common misconceptions about hypnosis and identified important social and cognitive determinants of suggestibility, and clinicians have recognized the promise of hypnosis in treating an array of psychological and medical conditions.

Recognizing the need for a theoretically neutral definition of hypnosis, the American Psychological Association (APA) Division of Psychological Hypnosis (1994) arrived at a consensus definition of hypnosis as a procedure in which a researcher or mental health professional provides suggestions to a participant, client, or patient for changes in sensations, perceptions, thoughts, or behaviors. A decade later, the APA reformulated the definition to encompass self-hypnosis in which individuals self-administer suggestions, usually following practice in responding to hypnotist-facilitated suggestions.

Typically, a hypnosis session begins with a so-called “induction,” followed by specific suggestions for a variety of experiences and physical responses such as overt movements, pain relief, and alterations in memory, including amnesia. Many inductions include suggestions for relaxation and deepening of the hypnotic experience, which serve to define the context as hypnosis and increase suggestibility to a small degree—typically 10–15%. Many hypnotic inductions (e.g., hand levitation, eye fixation) can be used interchangeably, including ones that emphasize feeling alert and energized. Moreover, the way suggestions are worded (e.g., explicit versus open-ended, authoritative versus permissive) has little bearing on how people respond. Interestingly, properly motivated awake participants can experience virtually all hypnotic phenomena without a formal hypnotic induction.

People exhibit dramatic differences in hypnotic suggestibility. A variety of well-validated, standardized scales of hypnotic suggestibility have been developed, with laudable psychometric properties that rival those of intelligence tests. Approximately 15–20% of individuals are minimally suggestible (respond to 0–3 suggestions on a 12-item scale), 15–20% are highly suggestible (respond to 9–12 suggestions), and the remainder of the population scores in the medium range (respond to 4–8 suggestions) of hypnotic suggestibility.

Differences in suggestibility can be accounted for largely in terms of people’s attitudes, beliefs, and expectancies about hypnosis; their motivation and ability to imagine suggested events; and their ability to respond to waking imaginative suggestions apart from the context of hypnosis. To date, researchers have failed to identify a reproducible physiological signature of a “hypnotic trance.” However, suggested experiences (e.g., hallucination of color) have detectable psychophysiological concomitants, often similar to “actual” experiences (e.g., viewing a colored object). Thus, hypnosis can engender vivid and lifelike experiences (Woody & Szechtman, (2000)).

Facts about Hypnosis

Movies, the Internet, books, and magazines have fueled the popular imagination, while disseminating myths and misconceptions about hypnosis. Surveys indicate that many college students hold the popular yet mistaken beliefs that hypnotized participants (1) relinquish their free will and cannot resist suggestions; (2) are aware only of what the hypnotist suggests; (3) respond based on the skill of the hypnotist; and (4) can be made to tell the truth about things they would normally lie about.

Research also demonstrates that the following five beliefs do not square with scientific evidence (Nash, (2001)):

  1. Hypnosis is not a sleeplike state of consciousness. Most people describe their experience as focused attention on suggested events. Moreover, people can respond to hypnotic suggestions when they are wide-awake and while they pedal a stationary bicycle.

  2. Most hypnotized people are neither gullible nor faking nor merely complying with suggestions.

  3. Spontaneous amnesia for suggested events rarely develops.

  4. Hypnosis is not a dangerous procedure when practiced by well-trained professionals.

  5. Suggestibility can be increased significantly following training in how to imagine along with and in response to suggestions.

Theoretical Accounts

Historically, hypnosis has been viewed as producing an altered state of consciousness or trance. However, starting in the 1950s, Theodore Sarbin ((1950)) and later T. X. Barber ((1969)) contended that a special state or condition is not necessary to account for the behavioral and subjective responses associated with hypnosis. Other sociocognitve theorists, including Spanos, Chaves, Kirsch, Lynn, and Wagstaff, also rejected “trance” as an explanatory concept and argued that hypnotic responses are the product of individuals’ abilities, motivations, agendas, attitudes, beliefs, expectancies, attributions, and interpretations of the situation.

Dissociation theories have vied with sociocognitive models for attention and empirical support. According to Ernest Hilgard’s (1986) neodissociation theory, multiple cognitive systems or cognitive structures exist in hierarchical arrangement under some measure of control by an “executive ego” that is responsible for planning and monitoring functions of the personality. During hypnosis the hypnotist’s suggestions take much of the normal control away from the subject. An amnesic barrier prevents conscious awareness of how a person might bring about a suggested response via imagining, for example, thereby producing the impression of nonvolition that often accompanies hypnotic responses. Other dissociation theorists (e.g., Bowers, Woody) reject the idea of an amnesic barrier and argue that hypnotic suggestions bypass executive controls and directly activate suggested responses.

Paralleling theoretical developments in the broader skein of psychology, theorists have proposed accounts of hypnosis that rely on concepts derived from psychoanalysis (e.g., Fromm, Nash), neuroscience (e.g., Banyai, Gruzelier), cognitive psychology (e.g., Kihlstrom, McConkey, Sheehan), and communication theory (Lankton, Matthews, Yapko, Zeig). Each of these theories has garnered at least a modicum of empirical support.

Clinical Hypnosis

Although theoreticians disagree about the determinants of hypnotic suggestibility, a consensus exists among experts regarding the value of using hypnosis as an adjunct to psychotherapy. Meta-analyses reveal that hypnosis enhances the effectiveness of psychodynamic and cognitive behavioral psychotherapies. Controlled outcome studies also support the usefulness of hypnosis in treating anxiety, depression, and obesity. Moreover, patients who undergo hypnotic treatment for smoking cessation fare better than both patients on a wait list for treatment and patients who receive no treatment, implying that hypnosis can be a valuable intervention in a stepped-care approach to smoking cessation (Lynn, Kirsch, Barabasz, Cardena, & Patterson, 2000).

Hypnosis has been applied in individual and group settings, and with diverse populations including children, athletes, the elderly, marital couples in distress, and patients suffering from a variety of medical conditions. There is considerable support for the effectiveness of hypnosis in the preoperative preparation of surgical patients, the treatment of a subgroup of patients with asthma, and the treatment of patients with dermatological disorders, irritable bowel syndrome, hemophilia, and postchemotherapy nausea and emesis (Covino & Pinnell, in press). Hypnosis has proved to be very effective in alleviating acute and chronic pain, with 75% of the population receiving some benefit regardless of suggestibility level (Montgomery, DuHamel, & Redd, (2000)). There is a clear need for additional controlled outcome research that controls for the effects of relaxation and compares hypnotic interventions with a variety of alternative treatments and placebo conditions.

Hypnosis in the Legal Arena

Triers of fact have expressed considerable skepticism about admitting hypnotically elicited testimony to the bar. Court rulings have varied, with 27 states ruling hypnotically elicited recall as per se inadmissible, 4 states with precedents of per se admissibility, and 13 states considering evidence on a case-by-case basis. Many of the reservations concerning hypnosis center on research indicating that increases in accurate recall following hypnosis are often accompanied by even greater increases in inaccurate recollections. Importantly, hypnosis can also increase the confidence that witnesses hold in their memories, independent of the accuracy of the memories recovered. Accordingly, experts and courts have expressed concerns that, when witnesses hold unwarranted confidence in memories, it can render them resistant to cross-examination, thereby corrupting the judicial process. To date, few studies have addressed the issue of cross-examination. However, the available evidence indicates that hypnosis is not a reliable method for improving memory (Lynn, Barnes, & Matthews, in press).


Cognitive and social scientists, as well as mental-health professionals, have made important strides in demystifying hypnosis and mooring it to empirically supported theories, principles, and clinical practices. Our understanding of hypnosis will no doubt be advanced by new technologies, including neuroimaging techniques, that promise to illuminate the neurocognitive underpinnings of suggestions in hypnotic and nonhypnotic contexts. Clinicians can practice with assurance that hypnosis has the potential to enhance the effectiveness of a variety of psychotherapeutic interventions, and they can rely on a burgeoning literature to reassure patients that hypnosis is neither an occult nor a dangerous procedure. Moreover, triers of fact have a sound basis for appreciating the limitations and contraindications of the use of hypnosis for memory retrieval. Whereas the field of hypnosis has surely benefited from advances in psychological science more broadly, the study of hypnosis has the potential to enrich our understanding of how the power of words and communication can radically transform consciousness and behaviors.

  • Barber, T. X. (1969). Hypnosis: A scientific approach. New York: Van Nostrand Reinhold.
  • Covino, N., & Pinnell, C. (in press) Medical applications of hypnosis. In Lynn, S. J., Kirsch, I., & Rhue, J. W. (Eds.), Handbook of clinical hypnosis (2nd ed.). Washington, DC: American Psychological Association.
  • Hilgard, E. R. (1986). Divided consciousness: Multiple controls in thought and action (expanded ed.). New York: John Wiley & Sons.
  • Lynn, S. J., Barnes, S., & Matthews, A. (in press). Hypnosis and forensic science: Legal decisions and opinions. In Edwards, C. (Ed.), Handbook of forensic science. New York: Wiley.
  • Lynn, S. J., Kirsch, I., Barabasz, A., Cardena, E., & Patterson, D. (2000). Hypnosis as an empirically supported adjunctive technique: The state of the evidence. International Journal of Clinical and Experimental Hypnosis, 48, 343-361.
  • Montgomery, G. H., DuHamel, K. N., & Redd, W. H. (2000). A meta-analysis of hypnotically induced analgesia: How effective is hypnosis? International Journal of Clinical and Experimental Hypnosis, 48, 138-153.
  • Nash, M. R. (2001). The truth and hype of hypnosis. Scientific American, 285, 46-55.
  • Sarbin, T. R. (1950). Contributions to role-taking theory: I. Hypnotic behavior. Psychological Review, 57, 225-270.
  • Woody, E., & Szechtman, H. (2000). Hypnotic hallucinations: Toward a biology of epistemology. Contemporary Hypnosis, 17, 4-14.
  • Suggested Readings
  • Lynn, S. J., & Kirsch, I. (2006). Essentials of clinical hypnosis. Washington, DC: American Psychological Association.
  • Lynn, S. J., Kirsch, I., & Rhue, J. W. (Eds.). Handbook of clinical hypnosis (2nd ed.). Washington, DC: American Psychological Association.
  • Nash, M. R., & Barnier, A. (in press). Oxford handbook of hypnosis. New York: Oxford Press.
    Binghamton University
    Copyright © 2010 by John Wiley & Sons, Inc. All rights reserved.

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