On March 7, 1907, the English statistician Francis Galton published a paper which illustrated what has come to be known as the “wisdom of crowds” effect. The experiment of estimation he conducted showed that in some cases, the average of a large number of independent estimates could be quite accurate.

This effect capitalizes on the fact that when people make errors, those errors aren’t always the same. Some people will tend to overestimate, and some to underestimate. When enough of these errors are averaged together, they cancel each other out, resulting in a more accurate estimate. If people are similar and tend to make the same errors, then their errors won’t cancel each other out. In more technical terms, the wisdom of crowds requires that people’s estimates be independent. If for whatever reasons, people’s errors become correlated or dependent, the accuracy of the estimate will go down.

But a new study led by Joaquin Navajas offered an interesting twist (转折) on this classic phenomenon. The key finding of the study was that when crowds were further divided into smaller groups that were allowed to have a discussion, the averages from these groups were more accurate than those from an equal number of independent individuals. For instance, the average obtained from the estimates of four discussion groups of five was significantly more accurate than the average obtained from 20 independent individuals.

In a follow-up study with 100 university students, the researchers tried to get a better sense of what the group members actually did in their discussion. Did they tend to go with those most confident about their estimates? Did they follow those least willing to change their minds? This happened some of the time, but it wasn’t the dominant response. Most frequently, the groups reported that they “shared arguments and reasoned together”. Somehow, these arguments and reasoning resulted in a global reduction in error. Although the studies led by Navajas have limitations and many questions remain, the potential implications for group discussion and decision-making are enormous.

1.1. What is Paragraph 2 of the text mainly about?

A The methods of estimation.

B The underlying logic of the effect.

C The causes of people’s errors.

D The design of Galton’s experiment.

解析：选B。B主旨大意题。根据第二段的“This effect capitalizes on the fact that when people make errors, those errors aren’t always the same. Some people will tend to overestimate, and some to underestimate. When enough of these errors are averaged together, they cancel each other out, resulting in a more accurate estimate.”(这种效应利用了这样一个事实:当人们犯错误时，这些错误并不总是相同的。有些人倾向于高估，有些人倾向于低估。当足够多的这些误差被平均在一起时，它们就会相互抵消，从而得到更准确的估计。)而这就是“群体智慧效应”的基本逻辑。B项The underlying logic of the effect. 该效应的基本逻辑。故选B。

2.2. Navajas’ study found that the average accuracy could increase even if ________.

A the crowds were relatively small

B there were occasional underestimates

C individuals did not communicate

D estimates were not fully independent

解析：选D。D细节理解题。根据题干中的Navajas 把关键信息定位在第三段。根据“The key finding of the study was that when crowds were further divided into smaller groups that were allowed to have a discussion, the averages from these groups were more accurate than those from an equal number of independent individuals.”(这项研究的关键发现是，当人群被进一步分成更小的群体并允许进行讨论时，这些群体的平均值比同样数量的独立个体的平均值更准确。)  由此可知，即使人们的估算是经过小组讨论的，不是独立的，但平均值更准确，平均的估算准确度也会提高。D项estimates were not fully independent估算不是完全独立的。故选D。

3.3. What did the follow-up study focus on?

A The size of the groups.

B The dominant members.

C The discussion process.

D The individual estimates.

解析：选C。C 推理判断题。根据题干中的the follow-up study 可以把根据信息定位在最后一段，根据“In a follow-up study with 100 university students, the researchers tried to get a better sense of what the group members actually did in their discussion.”(在对100名大学生的后续研究中，研究人员试图更好地了解小组成员在讨论中实际做了什么) 由此可知，在后续的研究中，研究人员试图更好地了解小组成员讨论的过程。C项The discussion process.讨论过程。故选C。

4.4. What is the author’s attitude toward Navajas’ studies?

A Unclear

B Dismissive

C Doubtful

D Approving

解析：选D。D 观点态度题。根据最后一段中的“Although the studies led by Navajas have limitations and many questions remain, the potential implications for group discussion and decision-making are enormous.” (虽然纳瓦哈人领导的研究有局限性，还有许多问题，但对小组讨论和决策的潜在影响是巨大的)可知，作者对Navajas的研究持支持的态度。故选D。