A、They are hard to dismiss once attached to a certain group. B、They may have a negative impact on people they apply to. C、They p

"Stereotype" may sound like a bad word, but there’s nothing bad about it. For one thing, stereotypes are often accurate. When you ask people about their concept of stereotypes, they get it pretty much right. Also, stereotypes are often positive, particularly of groups that we ourselves belong to. Some of the statistical generalizations may be positive as some groups have reputations for being smart, for being loyal, for being brave, for all sorts of things that are not at all negative. And so there’s nothing inherently wrong about stereotypes.
   But there are problems with stereotypes. For one thing, they’re reliable insofar as they’re based on unbiased samples. But a lot of the information we get about human groups is through biased sources like how they’re represented in the media. And if these sources don’t give you an accurate depiction, your stereotype won’t be accurate.
   For example, many Jews have been troubled by Shakespeare’s depiction of Shylock. If the only Jew you know is Shakespeare’s Shylock, it’s going to be a very bad impression. So one problem with stereotypes is while we are good at drawing conclusions from them, often our information isn’t reliable.
   A second problem is that stereotypes, regardless of whether or not they’re accurate, can have a negative effect on the people that they apply to. And this is what psychologist, Claude Steele, described as stereotype threat. He has a vivid example of this. Here’s how to make African-Americans do worse on a math test. You have the test and you put on the test that they have to identify their race. The very act of acknowledging that they are African-Americans when given a test ignites in them thoughts of their own stereotype which is negative regarding academics and that makes them do worse. Want to know how to make a woman do worse on a math test? Same thing, get her to write down her sex.
   One recent study found a sort of clever twist on this. When Asian-American women are given a test and they’re asked to mark down their race, they do better than they would otherwise do. They’re reminded of a positive stereotype that boosts their morale. You ask them, on the other hand, to mark down their sex, they do worse because they’re reminded of a negative stereotype. That’s an example of how stereotypes have a potentially damaging effect on people.
Questions 19 to 22 are based on the recording you have just heard.
19. What does the speaker say about stereotypes?
20. What leads to the bias of stereotypes?
21. What does the speaker say is a problem with stereotypes?
22. What did one recent study find about stereotypes?