A、Remembering word definitions. B、Recognizing repeated numbers. C、Distinguishing between similar colors. D、Tasting sounds. D细节题。

Today let’ s talk about synesthesia, that’s a brain condition in which a person’ s senses are combined in a unusual ways. For example, a person with synesthesia may taste sounds. To them, a musical note may taste like ablack tea. Many people who have synesthesia experience intense colors when they hear specific words. For example, they might see a flash of pink every time they hear the word "jump". For a long time, many scientists were unconvinced that synesthesia really exists. So in the 1990s an experiment was done to find out for sure. Two groups were studied. One was a group of people who claim to experience colors when they heard certain words. The other was a controlled group, people who experience nothing out of the ordinary when hearing words. Each group was asked to describe the colors they thought of when they heard a list of spoken words. When the test was repeated, the difference between the two groups was startling. After just a week, the controlled group gave the same answers only a third of the time. But even a year of a half later, the synesthetic group gave the same answers 92% of the time. Clearly, this is not just a matter of memory. Scientists are still not sure just why synesthesia happens. But certain drugs are reportedly able to produce it artificially. So we all probably have brains with connections that could synesthesia. It’s just the connections normally are used in that way. Now listen to the following recording and answer questions 23 to 25.
23. What’s the one example of synesthesia that the professor mentions?
24. What was the purpose of the experiment the professor mentioned?
25. What were some of people in the study able to do?