The responses of a subject to induction suggestions are what we collectively refer to as a trance. These responses are a function of what suggestions are made and the subject's own preconceptions of what a hypnotic state is like.
These suggestions and preconceptions in turn are usually similar enough, even in nominally different methods of hypnosis, the produce common reactions in different subjects, which are usually taken as evidence of hypnotic induction. Indeed, hypnotic induction proceedings are often stereotyped enough so that what is really remarkable is not the similarity of the reactions among different subjects but the fact that there is so much variability.
With respect to an individual subject, the initial induction is a very important event. Although little has been written on this topic, it appears likely that the reactions obtained in this sessions will determine the subject's personal expectations concerning the hypnotic state and will tend to reappear in all subsequent sessions. Thus, individual reactions to hypnotic inductions tend to remain similar from session to session unless specific suggestions are made to vary them.
The signs of hypnotic induction can be divided into objective signs that the hypnotist can observe directly and subjective signs that the subject must be asked to describe. Some of the more common objective signs of hypnosis are the following:
1. Initial eyelid fluttering followed by eye closure.
2. Deep relaxation as evidenced by limpness of the limbs, lack of facial expression, and marked disinclination to move of talk spontaneously.
3. Literalness in the understanding and following of suggestions. Often hypnotic subjects behave as though their understanding of language is more primitive; metaphoric expressions or idioms may be given their literal meanings. A subject told to raise his hand, for example, may simply raise the hand alone while leaving the arm unmoved, or a subject told to write their name, may literally write "Your name."
4. In some subjects, there may be excessive salivation and swallowing or excessive tearing of the eyes during hypnosis.
5. A characteristic of a hypnotized subject that some would call a defining feature of hypnosis is the tolerance of the subject for inconsistencies or anomalies in experience or perception, that is, trance logic.
The signs of hypnosis, while common, are all high individual. One subject may display most of these responses and be only in a very shallow state, as measured by his responsiveness to suggestions.
Another may not show and of these signs and yet be in a very deep hypnotic state. After working with an individual subject often enough, the hypnotist will be able to gauge this subject's trance depth from his objective responses.
The subjective feeling accompanying hypnotic induction are even more variable. They often include one or more of the following:
1. Feelings of deep relaxation and disinclination to expend any kind of effort during hypnosis.
2. Feelings of bodily heaviness, more likely in the limbs during hypnosis.
3. Feelings of numbness, tingling, or dullness in the limbs and/or hands during hypnosis.
4. A feeling of floating.
A common phenomenon in hypnotic sessions is the development of what is usually called rapport between the subject and the operator. This means that the subject reacts only to suggestions made by the hypnotist and treats suggestions made by anyone else as part of the background stimuli or noise, which he ignores.
Some operators believe that this is an essential aspect of hypnosis, but, like all other characteristics of a trance, it probably results from either an explicit or an implicit suggestion. For example, if the hypnotist tells the patient, "Attend only to the sound of my voice," as is commonly done during induction, he or she is in effect specifically telling the subject in a literal manner not to respond to suggestions from any other person.
In experimental work, the subject's doubt that hypnosis occurred is usually irrelevant to the study. If it is important to convince a patient of the reality of trance induction and the preceding steps leave him unconvinced, then hypnosis should be re induced and the subject given some posthypnotic suggestions to perform, such as developing an amnesia for the number 6.