In his book The Tipping Point, Malcolm Gladwell argues that "social epidemics" are driven in large part by the actions of a tiny minority of special individuals, often called influentials, who are unusually informed, persuasive, or well-connected. The idea is intuitively compelling, but it doesn't explain how ideas actually spread. The supposed importance of influentials derives from a plausible-sounding but largely untested theory called the "two-step flow of communication": Information flows from the media to the influentials and from them to everyone else. Marketers have embraced the two-step flow because it suggests that if they can just find and influence the influentials, those selected people will do most of the work for them. The theory also seems to explain the sudden and unexpected popularity of certain looks, brands, or neighborhoods. In many such cases, a cursory search for causes finds that some small group of people was wearing, promoting, or developing whatever it is before anyone else paid attention. Anecdotal evidence of this kind fits nicely with the idea that only certain special people can drive trends. In their recent work, however, some researchers have come up with the finding that influentials have far less impact on social epidemics than is generally supposed. In fact, they don't seem to be required of all. The researchers' argument stems from a simple observation about social influence: With the exception of a few celebrities like Oprah Winfrey—whose outsize presence is primarily a function of media, not interpersonal, influence—even the most influential members of a population simply don't interact with that many others. Yet it is precisely these noncelebrity influentials who, according to the two-step-flow theory, are supposed to drive social epidemics, by influencing their friends and colleagues directly. For a social epidemic to occur, however, each person so affected must then influence his or her own acquaintances, who must in turn influence theirs, and so on; and just how many others pay attention to each of these people has little to do with the initial influential. If people in the network just two degrees removed from the initial influential prove resistant, for example the cascade of change won't propagate very far or affect many people. Building on the basic truth about interpersonal influence, the researchers studied the dynamics of social influence by conducting thousands of computer simulations of populations, manipulating a number of variables relating to people' s ability to influence others and their tendency to be influenced. They found that the principal requirement for what is called "global cascades"—the widespread propagation of influence through networks—is the presence not of a few influentials but, rather, of a critical mass of easily influenced people.

单选题 By citing the book The Tipping Point, the author intends to

【正确答案】 B

【答案解析】解析：细节题。根据题干关键词定位到第一段。The Tipping Point这本书认为社会流行潮是由少数有影响力人士引起的，然而作者认为这种观点并不能令人信服(it doesn’t explain how ideas actually spread)。进而引出下文的讨论：社会流行潮是如何传播的，有影响力人士在其中起了什么作用。因此B项“探讨有影响力人士在传播观点中的作用”为正确答案。A项“分析社会流行潮的后果”，原文提到的是起因(“social epidemics”are driven by…)。C项“例证人们对社会流行潮的直觉反应”、D项“描述有影响力人士的基本特征”，原文并没有提到。

单选题 The author suggests that the "two-step flow theory"

【正确答案】 D

【答案解析】解析：细节题。根据题干关键词定位到第二段。第一句对“two-step flow theory”的定义是the supposed(所谓的)importance of influentials derives from a plausible-sounding(听起来可行的)but largely untested theory(多半是未经证实的理论)，由此可以看出，作者认为这种理论需要可靠的证据来证实，因此D项正确。A项“可作为解决营销问题的方法”，这不是作者的暗示。B项“已经有助于解释某些流行趋势”，原文只是说seems to explain the…popularity，不是肯定语气。C项“赢得了有影响力人士的支持”，原文未提。

单选题 What the researchers have observed recently shows that

【正确答案】 A

【答案解析】解析：细节题。根据题干关键词定位到第三、四段。第三段指出：有影响力人士对社会流行潮的影响没有想象的那么大。第四段具体叙述研究者的观察发现。第一句指出，除了个别名人，多数有影响力的人都不可能与过多的人交往，因此影响力不会太大。第三句指出，社会流行潮形成的关键在于将影响随社交网络传递下去，随着社会交往的增多，流行潮的影响力也在增大。而最初的有影响力人士由于直接交往的人数有限，因此影响力不太大。由此可知，影响力的大小与社会交往相关，故A项为正确答案。