How Hypnosis Works
The word "hypnosis" comes from the name of a Greek god Hypnos, who presided over sleep. In the late1700s, Anton Mesmer brought the technique into popular consciousness in Europe and in 1843, Scottish physician James Braid coined the term, "hypnotism," for the experience that was passing in many circles as "animal magnetism."
Hypnosis places a person in a trance state that can resemble sleep, but is instead an altered state of consciousness more akin to a lucid dream. Often people in a trance are quite alert, but focused in a way that differs from their normal conscious state. Contrary to popular notions, subjects in a light trance may be aware of everything that is going on.
I've seen a person under hypnosis who, when instructed to raise her arm into the air, laughed hard at the fact that her arm was rising, though she seemed perfectly conscious in a way that ought to have enabled her to resist the instruction. Her arm went up and stayed there until the hypnotist gave her an alternative instruction. They looked at each other the whole time and even had a conversation with her arm high in the air.
The trance-state, which has its own ebb and flow, is the result of a trusting and cooperative process between the subject and the hypnotist. It is not one person controlling another, but can still provoke a pretty strong response.
"Hypnosis," says Kevin McConkey, President of the Australian Psychological Society and co-author of Hypnosis, Memory, and Behavior in Criminal Investigation, "is essentially a phenomenon that reflects genuinely experienced alterations of reality in response to suggestions administered by a hypnotist." The subject's testimony is what confirms the trance, although susceptibility varies among individuals. Those who are highly suggestive will behave as if going through truly significant cognitive alterations.
Hypnosis involves concentration that is heightened to the point where one can recall details that seemed to elude that same person in a conscious state. That's why it appears to be a powerful tool for criminal investigation, although some researchers challenge the notion that hypnosis leads to significant increases in memory.
According to psychologists Mark King and Charles Citrenbaum, who both specialize in hypnosis as part of psychotherapy and who authored Existential Hypnosis, one must master three principles in order to do effective trance induction:
- Direct the subject toward detailed focused attention and explain that it is a process of focus and refocus.
- Be flexible in reading what the subject responds to.
- Mirror the rhythm of the subject's experience (as seen in breathing patterns and the pace of any verbalization).
Under hypnosis, subjects become attentive, focused, and less prone to critical judgment that can block memory. They slow down their thinking processes. Going into a trance purportedly allows the heightening of imagination, with the hope that some detail of a specific incident might be recalled that would otherwise remain inaccessible. Hypnosis, some say, bypasses a person's psychological defenses and taps into repressed material.
It does seem to be the case that trauma can close off memory of certain events. That means that crime victims may not be able to recall crucial details when bringing the material to consciousness feels too dangerous. A trance-induction can help them relax and feel safe enough to allow those details to surface.
Hypnotic techniques differ from one professional to another, but generally the hypnotist acts as the guide and uses suggestion to induce material. There is a pre-hypnosis interview to collect information, especially about how much a subject actually remembers about a target incident. Then how the professional puts someone into a trance can run the gamut from using a finger in motion, the way Bryan did with DeSalvo, to relying on a rhythmic instrument such as a metronome or flashing light. Along with these instruments, the hypnotist may "seed" the suggestive instruction with images of comfort, depth, and peacefulness. A visualization exercise that features a serene place may also help.
In criminal investigations, the sessions should proceed in a comfortable, quiet room and all interactions between subject and hypnotist should be recorded or videotaped. The hypnotist must thoroughly explain the structure of the session and put to rest any anxiety on the part of the subject. In the interview, the hypnotist should allow a free-ranging narrative of the event, refraining from leading questions. Then the subject's susceptibility and recall are tested. Finally, the trance is induced to explore specific aspects of the target incident. A debriefing follows, and the hypnotist writes up an evaluation of the session for investigators.
An example of how this works is found in a case involving the New York City Police Department's Hypnosis Unit. The unit was called when the investigation of a murder had only one lead — a witness who had seen a car driving away and could recall only one number of the license plate. He had a stammer, which made it difficult to interview him, but under hypnosis, his stammer disappeared and the man recalled all of the numbers on the license plate, many details of the actual shooting, a description of the suspect, and a conversation that he had overheard but had forgotten. The investigator verified the information through independent means and solved the case.
James W. Kenny, a retired FBI agent who owns an investigation agency in San Antonio, Texas offers services that include forensic hypnosis, handwriting analysis, and investigation of industrial espionage. While in the FBI, he conducted the bulk of the forensic hypnotic interviews used in major cases and while he calls hypnosis an "investigative asset," he says that it is no more reliable than other nonscientific techniques. "It does not stand alone," he points out, "but should always be independently verified. A law enforcement officer who interviews someone in a non-hypnotic interview has no idea if that person is telling the truth until he independently corroborates the information. The same holds true for a hypnotic interview."
Kenney goes on to say that the purpose of an interview using hypnosis is to get potential leads for resolving a particular matter. It can also eliminate people who were not really in a position to see or hear an incident. "Some people are pleasers or want to play an important role in something they were not involved in. Those people can be immediately discounted by someone trained in the technique."
Guidelines for the use of hypnosis in forensic investigations include:
- Keep it within the current laws and legal judgments.
- Make the subject's wellbeing the first priority.
- Avoid using hypnosis with young children.
- Elicit only material that can be corroborated with other investigation tools.
- The hypnotist should be a trained practitioner, not someone who has attended a seminar, and he or she should understand the legal parameters.
- The use of hypnosis should be determined to be appropriate to the case.
- The subject should be fully informed about the procedure and should put his or her consent in writing.
- Avoid using hypnosis with suspects or defendants, except under unusual circumstances, and stop the session if they talk about culpability.
While hypnosis may provide an effective tool in an investigation, bringing the results of hypnosis into court is quite another matter. Let's look at the early years of this type of testimony.