A) Hypnosis has been shown through

A) Hypnosis has been shown through a number of rigorously controlled studies to reduce pain, control blood pressure, and even make warts (肉赘) go away. But because very few studies have attempted to define the actual processes involved, most scientists are skeptical of its power and uses. That skepticism has driven David Spiegel, a professor of psychiatry at Stanford University School of Medicine, USA, and other researchers to take a hard look at what happens in the brain during hypnosis.B) Among researchers there are two schools of thought. One claims that hypnosis fundamentally alters subjects’ state of mind: they enter a trance (昏睡), which produces changes in brain activity. The other believes that hypnosis is simply a matter of suggestibility(易受他人影响) and relaxation. Spiegel belongs to the first school and over the years has had a debate with two scientists on the other side, Irving Kirsch, a University of Connecticut psychologist, and Stephen Kosslyn, a Harvard professor.