brain. They were saying that pulling on the rope need not make the bell ring. The bell itself —the mind— could stop it. This theory led to a great deal of research into how such factors as mood, gender, and beliefs influence the experience of pain. In a British study, for example, researchers measured pain threshold and tolerance levels in 53 ballet dancers and 53 university students by using a common measurement: after immersing your hand in body-temperature water for two minutes to establish a baseline condition, you put your hand in a bowl of ice water and start a clock running. You mark the time when it begins to hurt: that is your pain threshold. Then you mark the time when it hurts too much to keep your hand in the water: that is your pain tolerance. The test is always stopped at 120 seconds, to prevent injury.

The results were striking. On average female students reported pain at 16 seconds and pulled their hands out of the ice water at 37 seconds. Female dancers were almost three times as long on both counts. Men in both groups had a higher threshold and tolerance for pain, but the difference between male dancers and male nondancers was nearly as large. What explains that difference? Probably it has something to do with the psychology of ballet dancers — a group known for self-discipline, physical fitness, and competitiveness, as well as by a high rate of chronic(慢性) injury. Their driven personalities and competitive culture evidently accustom them to pain. Other studies along these lines have shown that outgoing people have greater pain tolerance and that, with training, one can reduce one’s sensitivity to pain.

There is also striking evidence that very simple kinds of mental suggestion can have powerful effects on pain. In one study of 500 patients undergoing dental procedures, those who were given a placebo(安慰剂) injection and promised that it would relieve their pain had the least discomfort — not only less than the patients who got a placebo and were told nothing but also less than the patients who got actual drug without any promise that it would work.

Today it is abundantly evident that the brain is actively involved in the experience of pain and is no more bell on a string. Today every medical textbook teaches the gate control theory as fact. There’s a problem with it, though. It explains people who have injuries but feel no pain, but it doesn’t explain the reverse, which is far more common — the millions of people who experience chronic pain, such as back pain, with no signs of injury whatsoever. So where does the pain come from? 50. The primary purpose of the passage is to A. describe how modern research has updated an old explanation

B. support a traditional view with new data

C. promote a particular attitude towards physical experience

D. suggest a creative treatment for a medical condition

51. Which statement best describes Descartes theory of pain presented in

paragraph 1?

A. The brain can shut pain off at will.

B. The brain plays no part in the body’s experience of pain.