Few ideas from social science have dug their way into the public imagination like Dunbar's Number, the famous finding that we humans can't cope with a social circle much larger than 150 people.The average size of modern hunter-gatherercommunities,it’s been calculated, is 148.8. The average size of army companies through history, from the Romans to the USSR, hovers around 150.And the average number of people to whom Britons nd Christmas cards, according to a 2003 study, is153.5. No wonder so many panic-merchants worry that online social networks will destroy society. To accumulate 1,000 Facebook friends, Dunbar's Number suggests, is to violate a law as old as humanity itlf.
In fact, the panic-merchants are wrong: Social networks don’t replace offline friendships. Nonetheless, Dunbar’s work does suggest something troubling about modern friendship. For centuries - and especially since the Industrial Revolution- we've been uprooting ourlves from the communities in which we were born. Until recently, on arriving in a new place, you'd inevitably lo your ties with the one you'd left; you'd be forced to invest fully in a new social circle. The days, however, thanks to email and Skype, you need never cut tho ties. You never leave your old life behind， so your emotional investments are scatter
ed.
魔方怎么拼六面One conquence is that the people in your circle of150 are far less likely to know each other. Or, as Dunbar writes, “Our social networks are no longer as denly interconnected as they once were.”Anyone who's ever fled small-town life might respond: Thank God for that.After all, there won't be people who are always snooping (窥探) on your business.
Yet it turns out that when clo friends know each other, good things happen. For example,Dunbar's rearch shows that people are more altruistic (利他的)toward each other in den social networks. Why are denly linked friends better friends? In a den network, an act of friendship is two things at once: an expression of an individual bond, and another stitch in a bigger social fabric.
春节四字祝福语Now you have a good reason to introduce your friends to each other. True, they’ll probably gossip about you at some point, but then that strengthens the social fabric, too.
21. According to the passage, Dunbar's Number is——
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A、 a method to calculate the average size of
modern human communities
B 、a public opinion on the potential influence
of online social networks
C、 a theory that states the limit of the size of电脑自动锁屏怎么取消
one’s social circle雷锋话
D 、a scientific concept that once influenced
human society in history
参考答案：C
22. The word “panic-merchants"(Para. 1) refers to people汽车覆盖件
——
A 、who have an inten fear of meeting
others through online social networks
B、 who worry about the big size of social
circles created by online networking
C、 who are afraid of the lack of privacy on
social networking websites
D、 who disbelieve the power of denly
connected social networks
参考答案：B
23. Which ofthe following statements is true according to the passage?
——
A 、Social networks are more scattered today than before the Industrial Revolution.
B 、Social networks are smaller today becau people spend more time online.
C 、Social networks become denr today due to the extensive u of the Internet.
D 、Social networks bear stronger emotional bonds today than centuries ago.
参考答案：A谁的青春不叛逆
24. According to the author, one bad thing about a den social network is that
——
A 、one’s business is hard to develop
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B 、one's privacy can be easily invaded
C、 one has few chances to meet new friends D one has to cut ties with friends in distant places
参考答案：B
25. What is the author's overall attitude toward den social networks?
——
A 、Indifferent.
B、 Unclear.
C 、Negative.
D、 Positive.
参考答案：D
