Research: Hypnosis is not sleep

The hypnotist, dangling a swinging pocket watch before the subject’s eyes, slowly intones: “You’re getting sleepy … You’re getting sleepy …” The subject’s head abruptly slumps downward. He is in a deep, sleeplike trance, oblivious to everything but the hypnotist’s soft voice. Powerless to resist the hypnotist’s influence, the subject obeys every command, including an instruction to act out an upsetting childhood scene. On “awakening” from the trance half an hour later, he has no memory of what happened.

In fact, this familiar description, captured in countless movies, embodies a host of misconceptions. Few if any modern hypnotists use the celebrated swinging watch introduced by Scottish eye surgeon James Braid in the mid-19th century. Although most hypnotists attempt to calm subjects during the “induction,” such relaxation is not necessary; people have even been hypnotized while pedaling vigorously on a stationary bicycle.
Electroencephalographic (EEG) studies confirm that during hypnosis subjects are not in a sleeplike state but are awake—though sometimes a bit drowsy. Moreover, they can freely resist the hypnotist’s suggestions and are far from mindless automatons. Finally, research by psychologist Nicholas Spanos of Carleton University in Ontario shows that a failure to remember what transpired during the hypnosis session, or so-called posthypnotic amnesia, is not an intrinsic element of hypnosis and typically occurs only when subjects are told to expect it to occur.
The iconic scene we described at the article’s outset also raises a deeper question: Is hypnosis a distinct state of consciousness? Most people seem to think so; in a recent unpublished survey, psychologist Joseph Green of Ohio State University at Lima and his colleagues found that 77 percent of college students agreed that hypnosis is a distinctly altered state of consciousness. This issue is of more than academic importance.
If hypnosis differs in kind rather than in degree from ordinary consciousness, it could imply that hypnotized people can take actions that are impossible to perform in the waking state. It could also lend credibility to claims that hypnosis is a unique means of reducing pain or of effecting dramatic psychological and medical cures.
Despite the ubiquitous Hollywood depiction of hypnosis as a trance, investigators have had an extremely difficult time pinpointing any specific “markers”—indicators—of hypnosis that distinguish it from other states. The legendary American psychiatrist Milton Erickson claimed that hypnosis is marked by several unique features, including posthypnotic amnesia and “literalism”—a tendency to take questions literally, such as responding “Yes” to the question “Can you tell me what time it is?”
We have already seen that posthypnotic amnesia is not an inherent accompaniment of hypnosis, so Erickson was wrong on that score. Moreover, research by Green, Binghamton University psychologist Steven Jay Lynn and their colleagues shows that most highly hypnotizable subjects do not display literalism while hypnotized; moreover, participants asked to simulate hypnosis demonstrate even higher rates of literalism than highly hypnotizable subjects do.
Other experts, such as the late University of Pennsylvania psychiatrist Martin Orne, have argued that only hypnotized participants experience “trance logic”—the ability to entertain two mutually inconsistent ideas at the same time. For example, a hypnotist might suggest to a subject that he is deaf and then ask him, “Can you hear me now?” He may respond “No,” thereby manifesting trance logic.
Nevertheless, research by the late Theodore X. Barber, then at the Medfield Foundation, and his colleagues showed that participants asked to simulate hypnosis displayed trance logic just as often as hypnotized people did, suggesting that trance logic is largely a function of people’s expectations rather than an intrinsic component of the hypnotic state itself.

By: Scott O. Lilienfeld and Hal Arkowitz