Question

    Two heads are better than one. After all, when trying to make decisions, it's good to have a second opinion. But what about a third, fourth — even twelfth? What group size is best for making decisions quickly? For ants, four to six heads surpass one ― and also outperform 12 or 24. That's what Sylvia Zamescu now reports.

The 18-year-old senior at Catalina Foothills High School in Tucson, Arizona isn't generally into ants. She's interested in decision-making, especially by people. Last summer, Sylvia read that social insects such as ants and bees can be used to model decision-making. Ants, for example, forage for food. When an ant finds it, it takes a bite and heads back to the nest. On the way; the ant leaves a scented trail for other ants to pick up. Back at the nest, the ant vomits up its meal into the mouth of other ants. Those nest-mates then decide with the first ant whether the food is good enough to deserve a trip back for more. If it is, they follow the first ant's scented trail to lunch.

When there are too few ants, it could take a long time for one ant to spread the word If there are too many, it's hard to “tell" each about the find. What's the right number for foraging success? Sylvia decided to find out. She contacted professors at the University of Arizona in Tucson to look for someone who would let her study decision-making by ants in their lab. Professor Wulfila Gronenberg answered her email.

Working with one of Wulfila's graduate students, Sylvia set up an experiment She tested the behavior of one, two, four, six, twelve and twenty-four ants. Each group was placed in a large box al taped "starting line". At the other end of the box were two bricks of sweetened gelatin （动物胶） one contained only 3 per cent sugar, and the other 30 per cent. Sylvia timed how long it took each group of ants to find the food. She also measured how much time they spent around each sweet treat.

When there were just one or two ants, the discovery was slow. The same was true when she set twelve or twenty-four ants loose. But four to six ants? Perfect! These medium-size groups found the food forest. They also figured out quickly that the sweeter food was better.

Similar work has been done on bighorn sheep, fish and fruit flies. "It may not be four to six animals, but it's the same principle," Sylvia says. A medium-size group "is optimal". So when faced with a new decision, two heads are better than one. But too many heads are too much. Like the ants, a good decision may just require a happy medium.

1.What gave Sylvia the idea for her research?

A.Her interest in social insects.

B.An article about social animals.

C.A university professor's invitation.

D.Her doubt about a science report.

2.What do we know about Sylvia's experiment?

A.She set it up with Professor Wulfila Gronenberg.

B.There were two large boxes at the "starting line".

C.There were several kinds of foods for the ants.

D.She divided the ants into six different groups.

3.What did Sylvia find out about ants?

A.They make decisions faster in medium-sized groups.

B.They are better at finding food in smaller groups.

C.They perform much more smartly in larger groups.

D.They make better decisions when working together.

Answer

1.B

2.D

3.A

【解析】

这是一篇说明文。尽管人们常说“人多智广”，但通过对蚂蚁，蜜蜂，菜蝇等的研究Sylvia Zamescu发现中等数量的群体有助于决定的做出。

1.细节理解题。根据文章第二段的The 18-year-old senior at Catalina Foothills High School in Tucson, Arizona isn't generally into ants. She's interested in decision-making, especially by people. Last summer, Sylvia read that social insects such as ants and bees can be used to model decision-making.可知Sylvia Zamescu原本对蚂蚁不是很感兴趣，但是读了关于社会群居动物的文章后，她决定用蚂蚁来做和决定有关的研究。B. An article about social animals.（一篇关于社会群居动物的文章）符合以上说法，故选B项。

2.细节理解题。根据文章第四段的Sylvia set up an experiment She tested the behavior of one, two, four, six, twelve and twenty-four ants.可知Sylvia在实验中把蚂蚁分成了数量不等的6组，来进行对比。D. She divided the ants into six different groups.（她把蚂蚁分成6个不同的组）符合文章内容，故选D项。

3.细节理解题。根据文章最后一段的"It may not be four to six animals, but it's the same principle," Sylvia says. A medium-size group "is optimal.可知Sylvia通过实验发现，中等数量的群体是做决定的最佳选择。A. They make decisions faster in medium-sized groups.(中等数量的群体时，做决定更快)符合以上说法，故选A项。