There are good reasons to be troubled by the violence that spreads throughout the media. Movies, Television and video games are full of gunplay and bloodshed, and one might reasonably ask what’s wrong with a society that presents videos of domestic violence as entertainment.
　　Most researchers agree that the causes of real-world violence are complex. A 1993 study by the U.S. National Academy of Sciences listed “biological, individual, family, peer, school, and community factors” as all playing their parts.
　　Viewing abnormally large amounts of violent television and video games may well contribute to violent behavior in certain individuals. The trouble comes when researchers downplay uncertainties in their studies or overstate the case for causality (因果关系). Skeptics were dismayed several years ago when a group of societies including the American Medical Association tried to end the debate by issuing a joint statement: “At this time, well over 1,000 studies... point overwhelmingly to a causal connection between media violence and aggressive behavior in some children.”
　　Freedom-of-speech advocates accused the societies of catering to politicians, and even disputed the number of studies (most were review articles and essays, they said). When Jonathan Freedman, a social psychologist at the University of Toronto, reviewed the literature, he found only 200 or so studies of television-watching and aggression. And when he weeded out “the most doubtful measures of aggression”, only 28% supported a connection.
　　The critical point here is causality. The alarmists say they have proved that violent media cause aggression. But the assumptions behind their observations need to be examined. When labeling games as violent or non-violent, should a hero eating a ghost really be counted as a violent event? And when experimenters record the time it takes game players to read ‘aggressive’ or ‘non-aggressive’ words from a list, can we be sure what they are actually measuring? The intent of the new Harvard Center on Media and Child Health to collect and standardize studies of media violence in order to compare their methodologies, assumptions and conclusions is an important step in the right direction.
　　Another appropriate step would be to tone down the criticism until we know more. Several researchers write, speak and testify quite a lot on the threat posed by violence in the media. That is, of course, their privilege. But when doing so, they often come out with statements that the matter has now been settled, drawing criticism from colleagues. In response, the alarmists accuse critics and news reporters of being deceived by the entertainment industry. Such clashes help neither science nor society.

　　21.   Why is there so much violence shown in movies, TV and video games?
　　A) There is a lot of violence in the real world today.
　　B) Something has gone wrong with today’s society.
　　C) Many people are fond of gunplay and bloodshed.
　　D) Showing violence is thought to be entertaining.

　　22.   What is the skeptics (Line 3. Para. 3) view of media violence?
　　A) Violence on television is a fairly accurate reflection of real-world life.
　　B) Most studies exaggerate the effect of media violence on the viewers.
　　C) A causal relationship exists between media and real-world violence.
　　D) The influence of media violence on children has been underestimated.

　　23.   The author uses the term “alarmists” (Line 1. Para. 5) to refer to those who ________.
　　A) use standardized measurements in the studies of media violence
　　B) initiated the debate over the influence of violent media on reality
　　C) assert a direct link between violent media and aggressive behavior
　　D) use appropriate methodology in examining aggressive behavior

　　24.   In refuting the alarmists, the author advances his argument by first challenging ________.
　　A) the source and amount of their data
　　B) the targets of their observation
　　C) their system of measurement
　　D) their definition of violence

　　25.   What does the author think of the debate concerning the relationship between the media and violence?
　　A) More studies should be conducted before conclusions are drawn.
　　B) It should come to an end since the matter has now been settled.
　　C) The past studies in this field have proved to be misleading.
　　D) He more than agrees with the views held by the alarmists.