人教高考英语阅读理解分类训练：文化类.docx

阅读理解
Move Over, Selfish Gene
Evolution traditionally has a problem with nice people. If only the fittest individuals survive, then those who are nice to others at their own expense will surely be weeded out. Yet cooperation is widespread in nature, from plants alerting each other to danger to dolphins cooperating to round up fish.
A decades-old idea called kin selection can explain some of this: if organisms (生物) have enough DNA in common, then they can further their own selfish genes by helping one another. Bees and ants have a system of reproduction which leaves colony members so closely related that they act almost as a single super-organism. And among any sexually reproducing species, parental care helps individuals pass on their genes.
But kin selection cannot explain why humans are so nice to strangers. One idea is that we have evolved to be super-cooperative because, over time, more cooperative groups have outcompeted less cooperative ones. But there generally isn’t enough genetic variation between groups to allow natural selection to favor more cooperative ones.
Some researchers think the solution lies in an idea called cultural group selection. Forget shared genes, they argue. Selection can favor cooperative groups if the people within them share enough culture. The idea is controversial because to work it requires that groups remain culturally distinct. As critics point out, people tend to migrate (迁移) between groups, which should homogenize (使同质化) ideas and customs. Those who back the concept counter that groups have ways to maintain their distinct culture, including a process called norm (准则) enforcement. Put simply, if someone migrates into a new cultural group, they are pressured into following the local rules because failing to do so leads to punishment.
Earlier this year, Mathew and Handley at Arizona State University published a study testing the idea. They sampled 759 people from four ethnic groups in Kenya who compete intensively for land, w