The fact that the vast majority of people (under the proper circumstances) can easily make the shift from conscious to unconscious functioning makes hypnotherapy an extremely valuable tool in treatment procedures: hypnotized individuals may be successfully instructed to dissolve old personality complexes, eliminate simple phobias, enhance their self-esteem, have improved recollection, prompt remission of many physical symptoms, reduce or eliminate pain or cause muscle responses at discrete locations not ordinarily subject to conscious or volitional control (Overlade, 1976).
There are two reasons why it is important for investigators to have at least a minimal understanding of the ease with which a person can shift (or be prompted to shift) to an unconscious level of functioning. First, so that they can appreciate how a very minor and unwitting variation in language might produce different responses. For example, witnesses to an accident can be expected to give more affirmative responses to the question, "Did you see the broken headlight?" Still fewer reports of broken headlights would be given to the direction, "Tell me everything you remember about the car." Not just the wording of inquiry, but facial expressions and intonation can signal the cooperative witness (at an unconscious level) what answer might be desired or be consonant with the belief system of the investigator. Most investigators fully appreciate the need for objectivity and the importance of not leading a possible UFO or alien percipient; consideration of investigative field reports makes it clear that many succeed in exercising these cautions and are not easily persuaded that an encounter has occurred. At the same time, it can be safely said that the ranks of volunteer investigators are not equally balanced between those tilting toward belief and those tilting toward skepticism--and investigators are no less subject to the human predilection to seek confirmation of their own belief systems than the rest of the population. Unconscious bias in the investigator can influence the unconscious belief system of the percipient.
More permissive, less demanding questions such as, "Can you clarify that for me?" or "Can you remember any more about that?" or "Is there any more you would like to tell me about that?" (Clark, S., in MUFON Field Investigator's Manual, 3rd Edition, p. 137) offer some limited protection against the creation of false memories--either at the time of the investigator's inquiry or later, during hypnotic inquiry.
A second reason why it is important for investigators to understand how easily a person can be shifted from conscious to unconscious functioning is so they will appreciate the limitations of hypnotic regressions--even when these are carried out by highly qualified, trained and experienced professional hypnotherapists. Even the seemingly innocent question, "Tell me all you remember," implies: "You have a memory of an event, you will recall it and you will relate it to me." These implied directives, coupled with the cooperative percipient's strong desire (sometimes eagerness!) to fill in gaps and to contribute to the understanding of the phenomena under study, can strongly motivate the hypnotized subject to embellish, introduce "memories" of thoughts actually experienced after (or before) the subject event, distort or displace memories in time sequence, or even completely fabricate a "memory" that seems plausible to the unconscious of the abductee. Throughout the balance of this chapter the word "abductee" will be used to mean possible, potential or apparent abductee. Such fabrications developed within the hypnotic state and at an unconscious level take on (for the percipient) a high level of credibility, are not subject to the censor of their usual honesty and are incorporated into their belief system to an extent which could protect these deceits from detection by polygraph testing. Quite aside from such fabrication, the investigator should understand that hypnosis is not in any sense a "truth serum" (indeed, a truth serum doesn't guarantee truth) and the fraudulent person can lie under hypnosis as readily as he can in the waking state.