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A new study says one part of the human brain may become smaller as the result of a condition known as jet lag. Jet lag results from flying long distances in an airplane. People with jet lag feel extremely tired for several days. They may also have problems in thinking clearly and remembering.
Recently a researcher at the University of Bristol in Britain reported the findings of his jet lag study, which involved twenty women who worked for international airlines. They had served passengers on airplanes for five years. These flight attendants flew across many countries and at least seven time zones. In the study, the flight attendants had different amounts of time to recover from jet lag. Half the women spent five days or fewer in their home areas between long flights. The other half spent more than fourteen days in their home areas.
The researcher took some saliva from the women’s mouths to measure levels of a hormone (荷尔蒙 ) that increases during stress . He tested them to see if they could remember where black spots appeared on a computer screen .And he took pictures of their brains to measure the size of the brain’s temporal lobes. (脑叶).
It was found that the women who had less time between flights had smaller right temporal lobes. This area of the brain deals with recognizing and remembering what is seen. The same group performed worse and had slower reaction times on the visual memory test. And their saliva samples showed higher levels of stress hormones.
The researcher believes the brain needs at least ten days to recover after a long trip. He says airline workers told him their ability to remember got worse after working on planes for about four years. Other studies have shown that increased feelings of stress can cause a loss of cells in the part of the brain that controls memory.
Scientists say more tests are needed to study the effects of jet lag on the brain. They want to find out if too much jet lag could permanently affect memory.
47．According to the text, jet lag _____.
A. can cause difficulties in speaking
B. can make people feel tired for a few weeks
C. can be only found in flight attendants
D. can be caused by flying over several time zones
48．It can be inferred from the text that ______.
A. the conclusion is refused by many scientists
B. scientists fear that this research is not done properly
C. every scientific conclusion needs the support from many tests
D. the women who were examined in the research were not healthy
49．From the result of the research we can see that _____.
A. the women who have longer rest at home perform better on the test.
B. the women who fly in short time have smaller right temporal lobes
C. the women who have longer flights fail the memory test
D. the women who rest more than 14 days produce more hormones
50．What is the subject discussed in the test?
A. The cause of jet lag.
B. A story of a group of flight attendants.
C. The importance of having enough rest after flights.
D. A research about the effects of jet lag on the brain.
查看习题详情和答案>>We may all have had the embarrassing moment：Getting halfway through a story only to realize that we've told this exact tale before to the same person. Why do we make such memory mistakes?
According to the research published in Psychological Science, it may have to do with the way our brains process different types of memory.
Researchers Nigel Gopie, of the Rotman Research Institute in Toronto, and Colin Macleod, of the University of Waterloo, divided memory into two kinds. The first was source memory，or the ability to keep track of where information is coming from. The second was destination memory，or the ability to recall who we have given information to.
They found that source memory functions better than destination memory, in part because of the direction in which that information is travelling.
To study the differences between source memory and destination memory, the researchers did an experiment on 60 university students, according to a New York Times report. The students were asked to associate (联想) 50 random(随意的) facts with the faces of 50 famous people. Half of the students“told”each fact to one of the faces, reading it aloud when the celebrity's(名人的) picture appeared on a computer screen. The other half read each fact silently and saw a different celebrity picture afterward.
When later asked to recall which facts went with which faces, the students who were giving information out(destination memory)scored about 16 percent lower on memory performance compared with the students receiving information(source memory)．
The researchers concluded that outgoing information was less associated with its environmental context (背景)—that is，the person—than was incoming information.
This makes sense given what is known about attention. A person who is giving information, even little facts, will devote some mental resources to thinking about what is being said. Because our attention is limited，we give less attention to the person we are giving information to.
After a second experiment with another group of 40 students, the researchers concluded that selffocus is another factor that undermines destination memory.
They asked half the students to continue giving out random information, while the other told things about themselves. This time around, those who were talking about themselves did 15 percent worse than those giving random information.
“When you start telling these personal facts compared with nonself facts, suddenly destination memory goes down more, suggesting that it is the selffocus component (成分) that's reducing the memory.”Gopie told Live Science.
60．The point of this article is to ________.
A. give advice on how to improve memory
B. say what causes the memory to worsen
C. explain why we repeat stories to those we've already told them to
D. discuss the differences between source memory and destination memory
61．What can we learn from the article?
A. Source memory helps us remember who we have told the information to.
B. One's limited attention is one of the reasons why those reading aloud to the celebrity's pictures perform worse on the memory test.
C. Silent reading is a better way to remember information than reading aloud.
D. It tends to be more difficult for people to link incoming information with its environmental context than outgoing information.
62．The underlined word“undermines” probably means________.
A. weakens B. benefits
C. explains D. supports
63．What did the scientists conclude from the second experiment?
A. Destination memory is weaker than source memory.
B. Focusing attention on oneself leads to relatively poor source memory performance.
C. Associating personal experience with information helps people memorize better.
D. Selffocus is responsible for the reduction of destination memory.
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