What Is Hypnosis?

Why, everybody knows what hypnosis is! It’s … *rummages for the dictionary* a noun referring to “a state like sleep in which the subject acts only on external suggestion.”​(Barber, 2004)​

Hmm. That’s not quite right. Maybe I need a more specialised dictionary. The Oxford Dictionary of Psychology has it as, “Alterations in sensations, perceptions, thoughts, feelings, or behaviour brought about by suggestion, often (though controversially) interpreted as a trance-like altered state of consciousness characterized by heightened suggestibility, associated with such phenomena as suggested hallucinations, hypnotic analgesia, hypnotic amnesia, and hypnotic age regression. Also called hypnotism or mesmerism.” ​(“Hypnosis,” 2015)​ That’s somewhat better, but …

Well. Perhaps I do need to address it myself.

This is not actually a simple question

“If you ask n experts, you will get n+1 answers” is so common a sentiment across fields as to be cliché, but it does reflect the lack of consensus among hypnotists and researchers about the nature of what they do. The American Psychological Association’s Society of Psychological Hypnosis, for example, first published a formal definition in 1994; this was immediately attacked for being too long, and for being too limited. Complaints were made that the notion of hypnosis as a distinct state was not mentioned, and suggested that this indicated a theoretical bias that was not representative of members’ beliefs. ​(Elkins, Barabasz, Council, & Spiegel, 2015)​ When members of the British Society of Experimental and Clinical Hypnosis were asked about their agreement with the definition, only about 70% of those who responded felt that their organisation should adopt the APA definition without significant changes. ​(Fellows, 1994)​

Almost immediately after publication of the definition in 1994, the executive committee of APA Division 30 began to address these concerns; however, the revision proved to be a very challenging task, and the 1994 definition served for more than a decade. Initially, several subcommittees were formed with the goal of examining the language and developing a more clearly stated definition. However, none of these committees succeeded in achieving a consensus, and in 2002, the previous committees were dissolved

​(Elkins et al., 2015)​

The American Psychological Association released new definitions in 2003, and again in 2014; each time, their attempts met with immediate criticism and condemnation from some of the members of the Society of Psychological Hypnosis.

With these difficulties in mind, don’t expect a simple blog post to reach the One Ultimate and True definition of hypnosis. Rather, let’s aproach this as an exploration of ways hypnosis might be conceptualised, and some of the shortcomings of those concepts as definitions.

In the beginning …

Part of the difficulty in finding a suitable definition of hypnosis is that our understanding of the phenomenon has changed in the centuries since James Braid coined the term. In 1843, his understanding of hypnotism was as a “nervous sleep”, which is reflected in the general dictionary definition to this day. ​(Braid, 1843)​

By 1855, Braid had himself recognised the difficulty with the term, admitting:

I am well aware that, in correct phraseology, the term hypnotism ought to be restricted to the phenomena manifested in patients who actually pass into a state of sleep, and who remember nothing on awaking of what transpired during their sleep. All short of this is mere reverie, or dreaming, however provoked; and it, therefore, seems highly desirable to fix upon a terminology capable of accurately characterising these latter modifications which result from hypnotic processes. This is the more requisite from the fact that, of those who may be relieved and cured by hypnotic processes of diseases which obstinately resist ordinary medical treatment, perhaps not more than one in ten ever passes into the state of oblivious sleep, during the processes which they are subjected to. The term hypnotism, therefore, is apt to confuse them, and lead them to suspect that, at all events, they cannot be benefited by processes which fail to produce the most obvious indication which the name imports.

​(Braid, 1855)​

He suggested, therefore, that “hypnotism” be restricted to cases that met the expectation of sleep, and that the term “monoideism” be used to “indicate the doctrine of the influence of dominant ideas in controlling mental and physical action.” To encompass both, he offered, “I think no term could be more appropriate than psycho-physiology.”

Nonetheless, we discuss “hypnotism” and “hypnosis” to this day, despite any confusion the etymology might cause to lexicographers and others.

Is hypnosis a state like sleep?


Modern neuroimaging techniques have allowed us to look at activity in the brain during different states, including sleep, hypnosis, and awake relaxation. Even if we look only at the “default mode network”, the screensaver the brain runs while not working on anything in particular, we see distinct differences. While default mode network activity is similar between REM sleep and alert relaxation, hypnosis has been observed to reduce activity in the default mode network. ​(Guldenmund, Vanhaudenhuyse, Boly, Laureys, & Soddu, 2012)​ Regardless of whether a hypnotised person looks “asleep” or how “dream-like” a hypnotic state may feel, hypnosis is neurologically distinct from sleep and dreaming.

I am only a hypnotist, therefore this is only a suggestion

Many of the tests that exist to measure hypnotic skill in subjects focus primarily on the subjects’ ability to respond to “suggestions” made by the hypnotist. ​(Kirsch, 1997)​ At the end of the nineteenth century, there was a significant faction arguing that hypnosis was nothing but suggestion. ​(Brancaccio, 2017)​

While suggestion may form an important active ingredient in hypnosis, not least because it’s what give us behaviours to measure, phenomenological investigations of hypnosis have shown differences between “hypnotised” and “non-hypnotised” meta-cognition and experience of self, even without specific suggestions to have those experiences. ​(Pekala, 2015)​

In addition to experiences of hypnosis other than suggestibility, the effectiveness of suggestions outside of hypnosis forbid us from considering the two phenomena entirely equivalent. The Cabinet Office in the United Kingdom, together with the Institute for Government, have investigated non-hypnotic methods of behavioural control beyond their normal scope of legislation and punishment. The acronym “MINDSPACE” acts as a mnemonic for some of these methods. This model considers the messenger, or source of information, as a factor that can either increase or decrease credibility; incentives, such as risk avoidance for fear of loss; norms, based on what we expect others would do; defaults, tending to accept the option offered when we don’t bother making a conscious choice; salience, looking at what strikes us as novel or important; priming by sub-conscious cues; our affective or emotional associations; a drive to keep commitments and appear consistent to ourselves; and aspects of choices that support our ego and self-image. ​(Dolan, Hallsworth, Halpern, King, & Vlaev, 2010)​ Any of these can form effective suggestion without relying on the relationship-building that typefies hypnosis.

Hypnosis is collaborative

Necessarily, hypnosis is a collaborative activity. The original 1994 American Psychological Association definition described hypnosis as a procedure “during which a health professional or researcher suggests that a client, patient, or subject experience changes in sensations, perceptions, thoughts, or behavior.” ​(Kirsch, 1994)​ While overly restrictive in its description of who can lead a hypnotic procedure — it defined stage hypnosis and self-hypnosis out of existence, for example — this definition did recognise the interaction as being key.

More than simple interaction, hypnosis involves hypnotist and subject working towards a common goal. In a medical setting, that shared goal might be for the subject to experience less distress from pain, or to find it easier to change habitual behaviour. On stage, that goal might be to entertain the audience, and it is vital for stage hypnotists to learn the skill of identifying subjects who are unprepared to collaborate on this project.

In his New Encyclopedia of Stage Hypnosis, Ormond McGill granted that some volunteers might initially simulate hypnosis rather than entering it easily on stage, but suggested this “is frequently born of a genuine desire to cooperate with the performer and help the show” and that dismissing them was not necessarily indicated. After all, “what begins as simulation can frequently transform into hypnosis.”

On the other hand, he warns, “It is a far cry from a subject simulating to help the show to the subject who deliberately pretends to be hypnotised just to fool you. This latter kind of person is dangerous, as he will try to make a fool of you.”

Subjects you should avoid and dismiss, as promptly as is diplomatic, are ones who sit with crossed legs or a “you show me” air. Likewise subjects who insist on talking to each other, chew gum, smoke, or smell of alcohol should be dismissed.

​(McGill, 1994)​

In addition to being disruptive to the show, this latter group of subject is unlikely to move from simulation to true hypnosis; there is no commonality of purpose between hypnotist and subject that would allow this to happen. In the instance of people who “smell of alcohol”, it’s not necessarily that they are not willing to collaborate; intoxication interferes with their ability to understand and follow instructions well enough to enact the co-operation they intend. Similarly, research has shown that children younger than seven score lower on tests of hypnotic ability, probably because of their still-developing facility with language and following instructions. Scores were also lower among teens over the age of fourteen, presumably due to lower inclination to collaborate with adults making strange demands. ​(London & Cooper, 1969)​

In clinical practice, rejecting a client is not so trivial a matter as dismissing a volunteer from a stage show, but the very issue that causes them to seek treatment can interfere with their ability to collaborate with the hypnotist. “By reason of their physical condition, state of tension or anxiety, intense interest, concern or absorption in their own behavior, they are unable to give either actively or passively the requisite cooperation to permit an effective alteration of their behavior.” ​(Erickson, 2009)​ Skilled hypnotists have a variety of techniques to assist these challenging clients in becoming more able to participate in the hypnotic collaboration because, simple or not, the collaboration is necessary for hypnosis to be possible.

Of course, we frequently collaborate with others without the interactions being hypnotic. While collaboration is a prerequisite to hypnosis, it does not alone form a definition.

How about “alterations in sensations, perceptions, thoughts, feelings, or behaviour”?

All of these can be elements of hypnosis, and are quite frequently the goal of hypnotic intervention. Pain management, for example, involves an alteration in the perception of pain; smoking cessation alters the behaviour of smoking. As a definition of hypnosis, however, there is a significant problem: many things cause “alterations of sensations, perceptions, thoughts, feelings, or behaviours” without being hypnosis. To give just one example for each:

Alteration of sensations
Food tastes better when one is hungry. ​(Zverev, 2004)​
Alteration of perception
Observers asked to count the number of times players pass a basketball typically fail to notice the passage of a person in a gorilla costume during the video. ​(Simons & Chabris, 1999)​
Alteration of thoughts
Joke books and lateral thinking puzzles often rely on using context to change the thoughts that come to mind. One fun example is asking one’s victim a series of questions such as, “What is the opposite of bottom?”, “What do you call an implement consisting of a sponge or a bundle of thick loose strings attached to a handle, used for wiping floors or other surfaces?”, “How do bunnies move around?”, and “What is another word for soda?” to prime an incorrect response* to the question, “What do you do when you come to a green light?​(“Five Fast Fill-Ins,” 2011)​
Alteration of feelings
Simply watching a film, or even a short film clip, is a reliable enough method of eliciting emotion to be used in psychological research. ​(Fernández-Aguilar, Ricarte, Ros, & Latorre, 2018)​
Alteration of behaviour
While most people may be unwilling to donate all of the money they have available to a stranger on the street, the addition of an implied threat such as, “Give me all your money, and nobody will get hurt” generally increases willingness to part with the funds requested. ​(Luckenbill, 1981)​

Defining hypnosis, then, only by looking at these alterations would mean that everything from skipping breakfast, to a night at the movies, to an armed robbery is hypnotic. Although some have argued that “everything is hypnosis” ​(Bandler, 2008)​, I view this claim as so broad as to eliminate any utility from using the word hypnosis at all. If everything is hypnosis, then nothing is hypnosis.

What about trance?

The question of trance would be easier to answer if trance were clearly defined. Rather than embarking on another long quest of definition, let’s consider for the moment a definition of “trance” that holds it to be a dissociative experience that results from “the behavior of an intense focusing of attention.” ​(Castillo, 1995)​

This definition seems to accord well with Spiegel’s description of hypnosis as “one extreme of the continuum of attention, involving an enhancement in focal concentration with a relative suspension of peripheral awareness.” He specified dissociation as one of “three main components” of hypnosis, explaining, “Dissociation is the mental separation of components of experience that would ordinarily be processed together. This may involve discontinuities in the sensations in one part of the body compared with another or a sense of involuntariness in motor functions, for example in the movement of one arm compared with the other.” ​(Spiegel, 1991)​

This sort of dissociation is responsible for the automaticity associated with hypnosis, the sense that behaviour is “1.) outside of awareness, 2.) uncontrollable (i.e., it cannot be prevented or stopped), 3.) unintentional (i.e., volitional effort is not needed for its initiation), and 4.) efficient (i.e., it does not consume attentional resources).” ​(Kirsch & Lynn, 1997)​ Gorassini’s model for this is one of “self-deception”; he argues, “From a cognitive-behavioral perspective, which also makes the assumption that suggested responses are voluntarily controlled, experiences of involuntariness arise when an actor uses self-deception as a means of experiencing hypnotic reality.” ​(Gorassini, 1999)​

Is trance, then, the key to hypnosis? It certainly seems to be an element, but it’s important to remember that, even aside from the everyday trances in which we absentmindedly perform tasks without conscious awareness, fully 89% of societies for which adequate ethnographic data was available demonstrated some form of institutional trance, ranging from spirit posession and speaking in tongues to meditation and prophetic dreaming. ​(Castillo, 1995)​ Once again, we have an element that seems to be part of hypnosis, but not synonymous with it.

Interestingly, subjects’ expectations of trance seem to reduce their ability to achieve hypnotic responses. This may be due an understanding of trance as something more mystical than the definition given above:

When participants’ experiences fail to meet their personal standards for successful hypnotic responding, they are likely to experience diminished role involvement (e.g., performance-related concerns, dissatisfaction) and dampened response expectancies that, in turn, inhibit performance.

​(Lynn, Vanderhoff, Shindler, & Stafford, 2002)​

Alternately, the self-evaluation required to self-assess whether they are in trance might itself interfere with the intense focusing of attention that Castillo described.

So, what is hypnosis?

Hypnosis clearly cannot be reduced to any of these elements, but rather seems to be formed of a gestalt of them. Suggestion, collaboration, and trance experiences can lead to short or long-term alterations in sensations, perceptions, thoughts, feelings, or behaviour. The exact borders are unclear, and a matter of over a century of research, so far.

More clear, and perhaps more fruitful to pursue in future blog entries, is the way in which hypnosis can be used to create change and improve lives. I look forward to exploring those questions with you in the future.


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