Before the Scottish physician James Braid coined the terms "hypnosis" and "hypnotism", the phenomena of hypnosis belonged to the fields of magnetism and Mesmerism. Magnetists and Mesmerists believed that an invisible universal fluid was responsible for their cures. In 1784 a commission investigating Mesmer stated that the cures were due to the imagination, not to magnetism. In response to criticisms, one of Mesmer's pupils, Charles d'Elson, wrote, "If Mesmer had no other secret than that he has been able to make the imagination exert an influence upon health, would he not still be a wonder doctor? If treatment by the use of the imagination is the best treatment, why do we not make use of it?"
Many people suffer from problems that are caused by the imagination. For example, the person with a fear of flying imagines the small space or turbulence, or, as Kroger describes in Clinical and Experimental Hypnosis, the example of a person who lacks confidence in public speaking:
"When in bed at night, he 'sees' himself walking up to the rostrum and 'hears' himself delivering his address. The mere thought of the future talk causes palpitation, sighing, holding of the breath and a panicky feeling. Thus, the imagination produces the same effects as if the speaker were in front of the audience. This process is referred to as sensory imagery. If his imagination is negatively 'programmed' in this manner, time after time, night after night, it is only natural that he will develop anxiety when he gets up to speak. Continually thinking negative, harmful and destructive thoughts eventually leads to their realization because of expectation and belief that they will happen. Having an idea of an action often results in that action."
The Law of Reversed Effect
Most people try to assert will power to solve their problems, but the Law of Reversed Effect says that the harder one tries to do something, the less chance there is of success. For example: the insomniac who makes a real effort to sleep (even though sleep cannot occur from effort), or the smoker who tries to stop by admonishing herself every time she smokes a cigarette. In hypnotherapy, more effective than the suggestion "You do not smoke" is the imagery of increased breath capacity, healthier skin, or greater peace of mind.
More than words
The unconscious responds more readily to the imagination than to hypnotic suggestions. When hypnotic suggestions are used, their greatest effect is not in their literal meanings, but in the imagined thoughts they produce. Words and phrases can produce powerful imagery, so a thoughtful hypnotist will be sensitive to the imagery that certain words may trigger in the imagination. Part of the task of the hypnotist is to determine what words are cues for specific imagery for the hypnotic subject.
Make it personal
Imagination can be reproductive (i.e. reproducing a previous experience or idea) or productive/constructive (creating something new). When using imagery in hypnotherapy, the subject's own recollections are more impactful than a newly created image. For example, to help someone increase confidence in public speaking, it is more effective to use his actual memories of times when he felt confident (in speaking or otherwise) than to describe an idealized image to which he cannot relate from personal experience. His own personal experiences are not forced on them, so he will accept them more readily.
Types of imagery
Imagination can be volitional (voluntary) or receptive (involuntary). Hypnotherapy and self-hypnosis can use both types. With receptive imagery, the images come without conscious effort. An example of using receptive imagery is to establish a purpose for entering hypnosis (ex: to remember something or to solve a problem), and then to observe passively what imagery occurs on its own, without exerting conscious effort.
Tips for using imagery:
- Close your eyes.
- Pay attention to details: colors, shapes, faces, attire, landscape, sounds, feelings, etc.
- Include all five senses. Imagination can be visual, auditory, olfactory (smell), gustatory (taste), and/or tactile (physical sensation).
- Be patient. Don't rush it or make hard work of it.
- If you are using volitional imagery, maintain a passive attitude when the mind wanders from the subject of focus, and return to it without judgment or frustration.
- Everyone already has the ability to imagine, so instead of waiting for something unusual or remarkable to happen, approach imagining as an opportunity to discern more closely how your imagination operates.
 Goldsmith, M. L. (1934). Franz Anton Mesmer; a history of mesmerism. Garden City, NY: Doubleday, Doran & Company, Inc.
 Kroger, William S. (1963). Clinical and Experimental Hypnosis. Philadelphia: J.B. Lippincott.