July Research Snippet: Competing Theories of Hypnosis

The Conditioning & Inhibition Theory of Hypnosis

In previous snippets, we’ve looked at factors in the typology of suggestion, some clinical outcome studies, etc., this month I’d like to draw attention to some research attempting to support a comprehensive theory of hypnosis.  As the psychologist Kurt Lewin famously remarked: “Nothing is as practical as a good theory.”  That phrase came to mind when reading Alfred Barrios’ recent series of articles which concisely and systematically outline a relatively simple “conditioning and inhibition” theory of hypnosis (Barrios, 2001), which recently led to an exchange with Steven Jay Lynn relating to the similarities and differences between Barrios’ theory and the influential “socio-cognitive” theory of hypnosis. 

            Barrios’ theory ultimately derives, I think, from the “cortical inhibition” theory of hypnosis which crowned Pavlov’s physiological research on animals at the turn of last century – a theory further developed by Platonov and other Soviet hypnotherapists.  Anyway, Barrios does an admirable job of carefully spelling out his modern variation, with intermittent references to supporting research data.  In a nutshell, Barrios draws on a revised form of conditioning theory to describe hypnosis as a method for reinforcing the subject’s tendency to progressively fade out (“inhibit”) intrusive thoughts and sensations in a way that heightens their sensitivity to learned associations between words, such as hypnotic suggestions, and physiological responses such as emotions.  From this point of view, words, such as verbal suggestions, function as stimuli which in turn evoke “cognitive stimuli” (ideas and images) in a way that triggers hypnotic responses.  Barrios’ use of behavioural learning theory obviously has the potential to highlight certain overlaps between the theory and practice of hypnosis and behaviour therapy. 

Barrios’ theory consists of the following seven hypotheses, divided into three groups,

A. Hypnotic induction

1. “Hypnotic induction is a conditioning process.”

2. “The response conditioned during hypnotic induction is an inhibitory set, a set which tends to inhibit stimuli incompatible with the response suggested by the hypnotist.”

3. “A positive response to a suggestion will induce within the responding person a more or less generalised increase in the normally existent tendency to respond to succeeding suggestions.”

B. Explanation of hypnotic phenomena

4. “A suggestion produces the desired response by first evoking a cognitive stimulus which is associated with that process.”

5. “The inhibitory set facilitates the suggested response by inhibiting stimuli competing with the cognitive stimulus.”

C. Post-hypnotic suggestion

6. “Suggestion leads to behaviour change by a form of higher-order conditioning called C-C [cognitive-cognitive] conditioning.”

7. “Hypnosis facilitates the C-C conditioning produced by suggestion.”

Barrios published two subsequent articles, the first of which explores the relationship between his “conditioning and inhibition” theory and four other modern theories of hypnosis: sociocognitive theory (Spanos/Lynn), Neo-dissociation (Hilgard), response expectancy (Kirsch), and Milton Erickson’s approach (Barrios, 2007).  The second reviews the possible benefits and applications of the theory to understanding phenomena such as the placebo effect, improving the effectiveness of hypnotic induction, improving post-hypnotic suggestions, and the development of Barrios’ therapeutic technique called Self-Programmed Control (Barrios, 2007b).

Comparison Between Theories

In the current edition of Contemporary Hypnosis, Steven Jay Lynn and Sean O’Hagen have responded in some detail to Barrios’ comparison between the conditioning and inhibition and sociocognitive theories of hypnosis.  

Sociocognitive theories reject the traditional view that hypnotic experiences require the presence of an altered state of consciousness.  Rather, the same social and cognitive variables that determine mundane complex social behaviours are said to determine hypnotic responses and experiences. (Lynn & O’Hagan, 2009)

They praise Barrios for providing a systematic and comprehensive account of his theory and its practical implications.  Indeed, contrary to Barrios’, they conclude that his theory is itself one of several falling under the broad “sociocognitive” umbrella term.  However, while endorsing some of his points, they disagree with others, citing several research studies in support of their own position.  In particular,

  1. Barrios emphasises the power of hypnotist prestige but sociocognitive researchers have generally found the qualities of the hypnotist to be of less importance than the qualities of the subject, e.g., their level of motivation, expectations, and imaginative capacity.
  2. Following Spanos, Barrios emphasises the power of “goal directed fantasies”, or mental imagery, in evoking hypnotic responses but, according to Lynn, research has failed to show that imagery alone can account for hypnotic responses without the aid of factors such as motivation and expectation.
  3. Barrios, like many hypnotherapists, naturally assumes that hypnotic suggestions are more effective when presented in order of difficulty, giving the subject an increasing confidence in their ability to respond. However, Lynn cites evidence from experimental studies showing that this is not the case and subjects respond just as well when suggestions are given in descending order of difficulty.
  4. They do, however, find support for Barrios’ contention that subjects increase in responsiveness to genuine suggestion tests after first being duped into believing they are hypnotised, e.g., by surreptitiously playing quiet music in the background while suggesting that they will hallucinate the sound of music, etc.
  5. They raise doubts over Barrios’ claim that some induction techniques induce hypnosis more “deeply” than others. Research has consistently failed to demonstrate much difference between different induction techniques.
  6. Moreover, the increase in suggestibility following hypnotic induction techniques is around 20% on average, which seems to show that the presence of a hypnotic state (“trance”), even if such a thing did exist, would be far less important to hypnotism than other factors such as the personality of the subject, their attitudes, and the type of suggestions given.

It’s truly fascinating to observe these debates between researchers from different theoretical traditions because they highlight the pros and cons of their respective points of view.  This is research in action; the competition between contrasting hypotheses, appealing to their respective supporting evidence.  It’s through this kind of dialogue that genuine progress is achieved in hypnotic research and we work our way gradually closer to an accurate and comprehensive theory of hypnosis and hypnotherapy. 


Barrios, A. A. (2001). A Theory of Hypnosis based on Principles of Conditioning & Inhibition. Contemporary Hypnosis , 18 (4), 163-203.

Barrios, A. A. (2007). Commentary on a Theory of Hypnosis based on Principles of Conditioning & Inhibition, Part I: Contrasts with Other Perspectives & Supporting Evidence. Contemporary Hypnosis , 24 (3), 109-122.

Barrios, A. A. (2007b). Commentary on a Theory of Hypnosis based on Principles of Conditioning & Inhibition, Part II: Benefits of the Theory. Contemporary Hypnosis , 24 (3), 123-138.

Lynn, S. J., & O’Hagan, S. (2009). The Sociocognitive and Conditioning and Inhibition Theories of Hypnosis. Contemporary Hypnosis , 26 (2), 121-125.