Hypnosis and consciousness
Explanation
Hypnosis is a state or technique that induces unusually intense responses to suggestions, with alterations in perception, memory, voluntary motor activity and/or sense of agency. Practised since Mesmer in the eighteenth century (with his disputed animal magnetism), it was refined by Braid (who coined the term in 1843) and clinically consolidated by Charcot, Bernheim, Janet and, partially, by Freud (who abandoned it in favour of free association). In the twentieth century it has been investigated with rigorous scientific methods.
Classic findings include that people vary enormously in hypnotic suggestibility (scales such as the Stanford Hypnotic Susceptibility Scale identify approximately 10% of very high hypnotisability and 10% of very low). Highly hypnotisable individuals can experience under hypnotic suggestion deep analgesia (sufficient for minor surgery without chemical anaesthesia), positive hallucinations (seeing what is not there) and negative ones (not seeing what is there), functional paralyses, age regressions, modifications of memory.
There are two great theoretical frameworks. State theories (Hilgard, Bowers) consider hypnosis to be an altered state of consciousness with its own characteristics: dissociation, focused attention, automaticity, suspension of critical judgement. Sociocognitive theories (Spanos, Kirsch) hold that hypnosis is not a special state, but a response to expectations and social roles: the hypnotised person acts as he believes a hypnotised person should act, motivated by suggestion and context.
Hilgard introduced the concept of the hidden observer to explain dissociative phenomena. In subjects hypnotised with analgesia, an apparently dissociated part of consciousness could report that it did indeed feel pain, although the central consciousness reported absence. This phenomenon suggests that hypnosis can induce functional dissociations between different aspects of mind, opening windows onto the structural plurality of consciousness.
Contemporary neuroscientific studies (with fMRI, EEG) show that in highly hypnotisable subjects, hypnotic suggestions produce neural changes corresponding to the reported experiences. For example, a suggestion of seeing colour over a grey stimulus activates colour-related visual areas; a suggestion of not seeing a word reduces the automatic processing of that word. These findings suggest that hypnosis modulates top-down cognitive processes in non-trivial ways.
For consciousness, hypnosis is a valuable tool for several reasons. It allows the study of functional dissociations in healthy people (not only in pathologies), exploration of the relations between suggestion and experience, investigation of the plasticity of perceptual and motor processes, and the development of clinical applications (analgesia, anxiety, habits, trauma). Debate continues about its ultimate nature (special state or set of cognitive-social capacities), but its usefulness as a window onto the mind and as a clinical tool is consolidated.
Strengths
- Demonstrates the plasticity and dissociability of consciousness.
- Clinical applications with robust evidence.
- Models such as hidden observer illuminate multiplicity of levels.
- Connection with dissociation, trance and other states.
Main critiques
- Unresolved debate over whether it is a special state or a social role.
- Enormous individual variability in suggestibility.
- Stigma and bad reputation due to non-clinical uses.