Hypnosis is a state of human consciousness involving focused attention and reduced peripheral awareness and an enhanced capacity for response to suggestion. The term may also refer to an art, skill, or act of inducing hypnosis.
The ability to be hypnotized has been described as heritable as shown in twin studies.
Theories explaining what occurs during hypnosis fall into two groups. Altered state theories see hypnosis as an altered state of mind or trance, marked by a level of awareness different from the ordinary conscious state. In contrast, nonstate theories see hypnosis as a form of imaginative role-enactment.
During hypnosis, a person is said to have heightened focus and concentration. The person can concentrate intensely on a specific thought or memory, while blocking out sources of distraction. Hypnotised subjects are said to show an increased response to suggestions. Hypnosis is usually induced by a procedure known as a hypnotic induction involving a series of preliminary instructions and suggestion. The use of hypnotism for therapeutic purposes is referred to as “hypnotherapy“, while its use as a form of entertainment for an audience is known as “stage hypnosis“. Stage hypnosis is often performed by mentalists practicing the art form of mentalism.
The term “hypnosis” comes from the Ancient Greek word ὕπνος hypnos, “sleep”, and the suffix -ωσις –osis, or from ὑπνόω hypnoō, “put to sleep” (stem of aorist hypnōs-) and the suffix –is. The words “hypnosis” and “hypnotism” both derive from the term “neuro-hypnotism” (nervous sleep), all of which were coined by Étienne Félix d’Henin de Cuvillers in 1820. These words were popularized in English by the Scottish surgeon James Braid (to whom they are sometimes wrongly attributed) around 1841. Braid based his practice on that developed by Franz Mesmer and his followers (which was called “Mesmerism” or “animal magnetism“), but differed in his theory as to how the procedure worked.
The hypnotized individual appears to heed only the communications of the hypnotist and typically responds in an uncritical, automatic fashion while ignoring all aspects of the environment other than those pointed out by the hypnotist. In a hypnotic state an individual tends to see, feel, smell, and otherwise perceive in accordance with the hypnotist’s suggestions, even though these suggestions may be in apparent contradiction to the actual stimuli present in the environment. The effects of hypnosis are not limited to sensory change; even the subject’s memory and awareness of self may be altered by suggestion, and the effects of the suggestions may be extended (posthypnotically) into the subject’s subsequent waking activity.
It could be said that hypnotic suggestion is explicitly intended to make use of the placebo effect. For example, in 1994, Irving Kirsch characterised hypnosis as a “nondeceptive placebo”, i.e., a method that openly makes use of suggestion and employs methods to amplify its effects.
The earliest definition of hypnosis was given by Braid, who coined the term “hypnotism” as an abbreviation for “neuro-hypnotism”, or nervous sleep, which he contrasted with normal sleep, and defined as: “a peculiar condition of the nervous system, induced by a fixed and abstracted attention of the mental and visual eye, on one object, not of an exciting nature.”
Braid elaborated upon this brief definition in a later work, Hypnotic Therapeutics:
The real origin and essence of the hypnotic condition, is the induction of a habit of abstraction or mental concentration, in which, as in reverie or spontaneous abstraction, the powers of the mind are so much engrossed with a single idea or train of thought, as, for the nonce, to render the individual unconscious of, or indifferently conscious to, all other ideas, impressions, or trains of thought. The hypnotic sleep, therefore, is the very antithesis or opposite mental and physical condition to that which precedes and accompanies common sleep
Therefore, Braid defined hypnotism as a state of mental concentration that often leads to a form of progressive relaxation, termed “nervous sleep”. Later, in his The Physiology of Fascination (1855), Braid conceded that his original terminology was misleading, and argued that the term “hypnotism” or “nervous sleep” should be reserved for the minority (10%) of subjects who exhibit amnesia, substituting the term “monoideism”, meaning concentration upon a single idea, as a description for the more alert state experienced by the others.
A new definition of hypnosis, derived from academic psychology, was provided in 2005, when the Society for Psychological Hypnosis, Division 30 of the American Psychological Association (APA), published the following formal definition:
Hypnosis typically involves an introduction to the procedure during which the subject is told that suggestions for imaginative experiences will be presented. The hypnotic induction is an extended initial suggestion for using one’s imagination, and may contain further elaborations of the introduction. A hypnotic procedure is used to encourage and evaluate responses to suggestions. When using hypnosis, one person (the subject) is guided by another (the hypnotist) to respond to suggestions for changes in subjective experience, alterations in perception, sensation, emotion, thought or behavior. Persons can also learn self-hypnosis, which is the act of administering hypnotic procedures on one’s own. If the subject responds to hypnotic suggestions, it is generally inferred that hypnosis has been induced. Many believe that hypnotic responses and experiences are characteristic of a hypnotic state. While some think that it is not necessary to use the word “hypnosis” as part of the hypnotic induction, others view it as essential.
Michael Nash provides a list of eight definitions of hypnosis by different authors, in addition to his own view that hypnosis is “a special case of psychological regression“:
3. T. X. Barber … defined hypnosis in terms of nonhypnotic behavioural parameters, such as task motivation and the act of labeling the situation as hypnosis.
4. In his early writings, Weitzenhoffer … conceptualised hypnosis as a state of enhanced suggestibility. Most recently … he has defined hypnotism as “a form of influence by one person exerted on another through the medium or agency of suggestion.”
5. Psychoanalysts Gill and Brenman … described hypnosis by using the psychoanalytic concept of “regression in the service of the ego”.
6. Edmonston … has assessed hypnosis as being merely a state of relaxation.
7. Spiegel and Spiegel … have implied that hypnosis is a biological capacity.
Joe Griffin and Ivan Tyrrell (the originators of the human givens approach) define hypnosis as “any artificial way of accessing the REM state, the same brain state in which dreaming occurs”, and they suggest that this definition, when properly understood, resolves “many of the mysteries and controversies surrounding hypnosis”. They see the REM state as being vitally important for life itself, for programming in our instinctive knowledge initially (after Dement and Jouvet) and then for adding to this throughout life. They explain this by pointing out that, in a sense, all learning is post-hypnotic, which explains why the number of ways people can be put into a hypnotic state are so varied: anything that focuses a person’s attention, inward or outward, puts them into a trance.
Hypnosis is normally preceded by a “hypnotic induction” technique. Traditionally, this was interpreted as a method of putting the subject into a “hypnotic trance”; however, subsequent “nonstate” theorists have viewed it differently, seeing it as a means of heightening client expectation, defining their role, focusing attention, etc. There are several different induction techniques. One of the most influential methods was Braid’s “eye-fixation” technique, also known as “Braidism”. Many variations of the eye-fixation approach exist, including the induction used in the Stanford Hypnotic Susceptibility Scale (SHSS), the most widely used research tool in the field of hypnotism. Braid’s original description of his induction is as follows:
Take any bright object (e.g. a lancet case) between the thumb and fore and middle fingers of the left hand; hold it from about eight to fifteen inches from the eyes, at such position above the forehead as may be necessary to produce the greatest possible strain upon the eyes and eyelids, and enable the patient to maintain a steady fixed stare at the object.
The patient must be made to understand that he is to keep the eyes steadily fixed on the object, and the mind riveted on the idea of that one object. It will be observed, that owing to the consensual adjustment of the eyes, the pupils will be at first contracted: They will shortly begin to dilate, and, after they have done so to a considerable extent, and have assumed a wavy motion, if the fore and middle fingers of the right hand, extended and a little separated, are carried from the object toward the eyes, most probably the eyelids will close involuntarily, with a vibratory motion. If this is not the case, or the patient allows the eyeballs to move, desire him to begin anew, giving him to understand that he is to allow the eyelids to close when the fingers are again carried towards the eyes, but that the eyeballs must be kept fixed, in the same position, and the mind riveted to the one idea of the object held above the eyes. In general, it will be found, that the eyelids close with a vibratory motion, or become spasmodically closed.
Braid later acknowledged that the hypnotic induction technique was not necessary in every case, and subsequent researchers have generally found that on average it contributes less than previously expected to the effect of hypnotic suggestions.Variations and alternatives to the original hypnotic induction techniques were subsequently developed. However, this method is still considered authoritative. In 1941, Robert White wrote: “It can be safely stated that nine out of ten hypnotic techniques call for reclining posture, muscular relaxation, and optical fixation followed by eye closure.”
When James Braid first described hypnotism, he did not use the term “suggestion” but referred instead to the act of focusing the conscious mind of the subject upon a single dominant idea. Braid’s main therapeutic strategy involved stimulating or reducing physiological functioning in different regions of the body. In his later works, however, Braid placed increasing emphasis upon the use of a variety of different verbal and non-verbal forms of suggestion, including the use of “waking suggestion” and self-hypnosis. Subsequently, Hippolyte Bernheim shifted the emphasis from the physical state of hypnosis on to the psychological process of verbal suggestion:
I define hypnotism as the induction of a peculiar psychical [i.e., mental] condition which increases the susceptibility to suggestion. Often, it is true, the [hypnotic] sleep that may be induced facilitates suggestion, but it is not the necessary preliminary. It is suggestion that rules hypnotism.
Bernheim’s conception of the primacy of verbal suggestion in hypnotism dominated the subject throughout the 20th century, leading some authorities to declare him the father of modern hypnotism.
Contemporary hypnotism uses a variety of suggestion forms including direct verbal suggestions, “indirect” verbal suggestions such as requests or insinuations, metaphors and other rhetorical figures of speech, and non-verbal suggestion in the form of mental imagery, voice tonality, and physical manipulation. A distinction is commonly made between suggestions delivered “permissively” and those delivered in a more “authoritarian” manner. Harvard hypnotherapist Deirdre Barrett writes that most modern research suggestions are designed to bring about immediate responses, whereas hypnotherapeutic suggestions are usually post-hypnotic ones that are intended to trigger responses affecting behaviour for periods ranging from days to a lifetime in duration. The hypnotherapeutic ones are often repeated in multiple sessions before they achieve peak effectiveness.
The conscious and the unconscious mind
Some hypnotists view suggestion as a form of communication that is directed primarily to the subject’s conscious mind, whereas others view it as a means of communicating with the “unconscious” or “subconscious” mind. These concepts were introduced into hypnotism at the end of the 19th century by Sigmund Freud and Pierre Janet. Sigmund Freud’s psychoanalytic theory describes conscious thoughts as being at the surface of the mind and unconscious processes as being deeper in the mind. Braid, Bernheim, and other Victorian pioneers of hypnotism did not refer to the unconscious mind but saw hypnotic suggestions as being addressed to the subject’s conscious mind. Indeed, Braid actually defines hypnotism as focused (conscious) attention upon a dominant idea (or suggestion). Different views regarding the nature of the mind have led to different conceptions of suggestion. Hypnotists who believe that responses are mediated primarily by an “unconscious mind”, like Milton Erickson, make use of indirect suggestions such as metaphors or stories whose intended meaning may be concealed from the subject’s conscious mind. The concept of subliminal suggestion depends upon this view of the mind. By contrast, hypnotists who believe that responses to suggestion are primarily mediated by the conscious mind, such as Theodore Barber and Nicholas Spanos, have tended to make more use of direct verbal suggestions and instructions.
The first neuropsychological theory of hypnotic suggestion was introduced early on by James Braid who adopted his friend and colleague William Carpenter’s theory of the ideo-motor reflex response to account for the phenomenon of hypnotism. Carpenter had observed from close examination of everyday experience that, under certain circumstances, the mere idea of a muscular movement could be sufficient to produce a reflexive, or automatic, contraction or movement of the muscles involved, albeit in a very small degree. Braid extended Carpenter’s theory to encompass the observation that a wide variety of bodily responses besides muscular movement can be thus affected, for example, the idea of sucking a lemon can automatically stimulate salivation, a secretory response. Braid, therefore, adopted the term “ideo-dynamic”, meaning “by the power of an idea”, to explain a broad range of “psycho-physiological” (mind–body) phenomena. Braid coined the term “mono-ideodynamic” to refer to the theory that hypnotism operates by concentrating attention on a single idea in order to amplify the ideo-dynamic reflex response. Variations of the basic ideo-motor, or ideo-dynamic, theory of suggestion have continued to exercise considerable influence over subsequent theories of hypnosis, including those of Clark L. Hull, Hans Eysenck, and Ernest Rossi. It should be noted that in Victorian psychology the word “idea” encompasses any mental representation, including mental imagery, memories, etc.
Braid made a rough distinction between different stages of hypnosis, which he termed the first and second conscious stage of hypnotism; he later replaced this with a distinction between “sub-hypnotic”, “full hypnotic”, and “hypnotic coma” stages. Jean-Martin Charcot made a similar distinction between stages which he named somnambulism, lethargy, and catalepsy. However, Ambroise-Auguste Liébeault and Hippolyte Bernheim introduced more complex hypnotic “depth” scales based on a combination of behavioural, physiological, and subjective responses, some of which were due to direct suggestion and some of which were not. In the first few decades of the 20th century, these early clinical “depth” scales were superseded by more sophisticated “hypnotic susceptibility” scales based on experimental research. The most influential were the Davis–Husband and Friedlander–Sarbin scales developed in the 1930s. André Weitzenhoffer and Ernest R. Hilgard developed the Stanford Scale of Hypnotic Susceptibility in 1959, consisting of 12 suggestion test items following a standardised hypnotic eye-fixation induction script, and this has become one of the most widely referenced research tools in the field of hypnosis. Soon after, in 1962, Ronald Shor and Emily Carota Orne developed a similar group scale called the Harvard Group Scale of Hypnotic Susceptibility (HGSHS).
Whereas the older “depth scales” tried to infer the level of “hypnotic trance” from supposed observable signs such as spontaneous amnesia, most subsequent scales have measured the degree of observed or self-evaluated responsiveness to specific suggestion tests such as direct suggestions of arm rigidity (catalepsy). The Stanford, Harvard, HIP, and most other susceptibility scales convert numbers into an assessment of a person’s susceptibility as “high”, “medium”, or “low”. Approximately 80% of the population are medium, 10% are high, and 10% are low. There is some controversy as to whether this is distributed on a “normal” bell-shaped curve or whether it is bi-modal with a small “blip” of people at the high end. Hypnotizability Scores are highly stable over a person’s lifetime. Research by Deirdre Barrett has found that there are two distinct types of highly susceptible subjects, which she terms fantasizers and dissociaters. Fantasizers score high on absorption scales, find it easy to block out real-world stimuli without hypnosis, spend much time daydreaming, report imaginary companions as a child, and grew up with parents who encouraged imaginary play. Dissociaters often have a history of childhood abuse or other trauma, learned to escape into numbness, and to forget unpleasant events. Their association to “daydreaming” was often going blank rather than creating vividly recalled fantasies. Both score equally high on formal scales of hypnotic susceptibility.