Neuroimaging studies are helping hypnosis shed its ‘occult’ connotations by finding that its effects on the brain are real.
By Lea Winerman
Mention hypnosis, and for many people the image that comes to mind is a charlatan with a watch swinging back and forth, seducing otherwise sensible audiences into barking like dogs or clucking like chickens. Today, though, psychologists and others are using hypnosis to help patients stop smoking, lose weight or control pain. But despite this newfound respect for the method, scientists still aren’t sure precisely how hypnosis–whether on stage or in a clinician’s office–works.
For years, they’ve been trying to determine whether hypnotized people actually feel and see things differently than the nonhypnotized or whether the hypnotized give in to some combination of concentration and social pressure to follow hypnotists’ demands.
Now, in the past decade or so and with the advent of neuroimaging technology like functional magnetic resonance imaging (fMRI), researchers have begun to get some answers.
Recent studies have found that when hypnotized people act on hypnotists’ suggestions, their brains really do process information differently. When they’re told to see colors, for example, the color-processing parts of their brains light up–despite the absence of any real color in front of them.
Another experiment found that hypnotically induced pain activated the same brain areas as “real” pain. In this 2004 study, published in Neuroimage (Vol. 23, No. 1, pages 392–401), University College London psychologist David Oakley, PhD, and his colleagues told eight highly hypnotizable participants that they would feel heat-related pain. They found that the same pain-processing areas of the brain–in the thalamus, anterior cingulate cortex and other areas–were active in those subjects as in subjects who actually touched a 120-degree metal probe. Subjects who simply imagined the pain, meanwhile, didn’t show the same active brain areas.
The accumulating evidence suggests that people respond to hypnotic suggestion by actually “feeling” or “seeing” the suggested stimulus, be it pain or color.
The question that researchers have yet to answer, Oakley says, is how those changes come about. Scientists are still split on the issue: Some believe that hypnosis puts people into a trance state in which the brain behaves measurably differently than it does in other states. Others, meanwhile, believe that hypnosis is simply an intense form of concentration or focused attention.
“We now have evidence showing that highly hypnotizable people do not need to be hypnotized in order to benefit from suggestion,” Raz says. That indicates that hypnosis may be a normal state of consciousness rather than an altered state–and that some people who are particularly good at experiencing imaginative suggestions are the ones who can be hypnotized, Kirsch explains.
Meanwhile, researchers who believe that hypnosis alters the brain’s functioning in some fundamental way say that the new findings don’t negate that possibility. John Gruzelier, PhD, a psychologist at Imperial College in London, acknowledges that easily hypnotizable people are more suggestible even when not hypnotized. However, he says, the hypnosis itself still makes a difference.
“It’s my feeling that we wouldn’t bother going through the whole rigmarole of hypnosis if it was unnecessary,” he says.
Raz and Kirsch hope that this and other work will also begin to help explain why some people are more highly hypnotizable than others, and will give researchers insight into who is most likely to benefit from hypnosis.
Monitor on Psychology
Volume 37, No. 3 March 2006
the complete article can be found here http://www.apa.org/monitor/mar06/lab.html