An arm floats upward without being lifted. A hand goes numb. A familiar name cannot be found. Twenty minutes pass in what feels like five. These are the hypnotic phenomena: the classic effects that make hypnosis so intriguing, and that therapists put to practical use.
A shared feature
What links them is a feeling of involuntariness. The arm does not feel lifted; it feels as if it is rising by itself. Researchers call this the classic suggestion effect, and it is the hallmark of a hypnotic response.
Not everyone experiences every phenomenon. The simpler ones are common. The more dramatic ones are mostly limited to highly hypnotizable people.
Movement phenomena
Ideomotor movements. Small movements that happen in response to an idea: a finger twitching, a pendulum swinging, an arm growing light and drifting upward (arm levitation).
Catalepsy. A limb or the eyelids become rigid or stay wherever they are placed. “Your eyelids are so relaxed they simply will not open” is a common early test.
Challenge suggestions. “Your hands are stuck together. Try to pull them apart.” The person tries and finds they cannot.
Sensory phenomena
Analgesia and anaesthesia. Reduced pain or numbness. This is the most clinically useful phenomenon and the best researched.
Hyperaesthesia. Heightened sensation, such as warmth or tingling in one hand.
Positive hallucination. Experiencing something that is not there: a fly buzzing, the scent of a rose, a voice.
Negative hallucination. Failing to perceive something that is there: not seeing a chair, not smelling ammonia.
Memory phenomena
Amnesia. Forgetting on suggestion, such as losing a number or being unable to recall the session until a cue is given. The memory is not erased. It returns when the suggestion is cancelled.
Hypermnesia. Apparently enhanced recall. This one needs caution. Research shows hypnosis increases how much people report and how confident they feel, without making them more accurate.
Age regression. The experience of being younger. It is an imaginative reconstruction, not a literal return.
Time and awareness
Time distortion. Time seems to speed up or slow down. People usually underestimate how long they were in hypnosis.
Dissociation. A sense of being detached from part of the body or from the surroundings, or of watching oneself from a distance.
After the session
Post-hypnotic suggestion. A response that occurs later, in reaction to a cue.
What causes them?
There are two broad explanations, and researchers still argue between them.
- Dissociation theories say that hypnosis divides mental control, so that actions are carried out without the usual sense of having willed them.
- Sociocognitive theories say the person is actively producing the response in line with their expectations, while sincerely experiencing it as happening to them.
Brain imaging supports the idea that the experiences are real. When highly hypnotizable people are given a suggestion to see colour in a grey image, activity changes in colour-processing areas of the brain. They are not merely saying it.
How therapists use them
| Phenomenon | Use |
|---|---|
| Analgesia | Pain control, dental work, procedures |
| Catalepsy and levitation | Convincers that build belief |
| Time distortion | Making a procedure feel shorter, or rest feel longer |
| Dissociation | Distance from pain or from distressing feelings |
| Amnesia | Rarely needed; sometimes to stop over-analysis |
| Post-hypnotic suggestion | Carrying change into daily life |
| Ideomotor movement | Signalling in deep hypnosis |
Do you need them for therapy to work?
No. Most therapeutic suggestions for stress, habits and confidence do not depend on any dramatic phenomenon. Many people who never experience arm levitation or amnesia still benefit.
Try one
Sit with your hands in your lap. Focus on one hand. Imagine a helium balloon tied to the wrist, tugging gently upward. Do not lift the hand and do not hold it down. Just imagine, and wait a minute or two. Many people feel lightness, a twitch, or a slow rise.
The bottom line
Hypnotic phenomena are real experiences produced by suggestion and imagination. They are fascinating in themselves, and the useful ones are everyday tools of clinical hypnosis.
Next in the series: Is Hypnosis a Special State? The Great Debate Explained
This article is for general information and is not medical advice.