单选题
An indigenous tribe in the Peruvian Amazon, the Mashco-Piro, has been trying to make contact with outsiders. In the past, the Mashco-Piro have always resisted interaction with strangers, avoiding—and sometimes killing—any they encounter. Most tribes have had a little, at least indirectly. 'There's always some contact with other isolated tribes, which have contact with other indigenous people, which in turn have contact with the outside world,' says Rebecca Spooner, of Survival International, a London-based organization that advocates for the rights of indigenous peoples. Many of the Amazon tribes choose to avoid contact with outsiders because they have had unpleasant encounters in the past. According to Glenn Shepard, an ethnologist at the Emilio Goeldi Museum in Belem, Brazil, this came after rubber companies massacred tribespeople at the turn of the 20th century. For this reason, some researchers refer to such tribes as 'voluntarily isolated', rather than uncontacted. More recent invasions, especially by miners, oil workers and loggers, may have reinforced the tribes' xenophobia (排外心理). A visiting New Scientist reporter was warned that any unclothed native should be regarded as uncontacted and, thus, very dangerous. In Peru, laws prohibit outsiders from initiating contact with isolated groups in most cases. They also provide protected areas where tribes can live in peace—but there are loopholes (漏洞) that allow oil and mining companies into the region. Brazil has similar laws and policies that allow contact only in life- threatening situations. Anthropologists have an ethical obligation to do no harm to their research subjects, according to the American Anthropological Association's Statement on Ethics. Often, they feel forced out by encroaching (逐渐渗透的) civilization, says Spooner. Survival International has documented some cases where settlements have been bulldozed (推倒) and tribespeople harassed—or even killed. This leaves the survivors feeling like they have no option but to give up. Others see a more benign (和善的) process at work, at least some of the time. 'Tribes may seek contact with outsiders because they begin to trust their intentions,' says Kim Hill, an anthropologist at Arizona State University. 'As soon as the tribes believe they might have some peaceful contact, all these groups want some outside interaction,' he says. 'It's a human trait to want to expand our contacts.' Modern medicine, metal tools and education can also exert a powerful pull. Often, there is a lot of disease because the tribespeople are exposed to novel germs. It is not uncommon for half the population to die of respiratory illness—unless outsiders bring sustained medical care, says Hill. Also, the newly integrated tribespeople frequently end up on the lowest rung of the society they join. Still. he says, when he interviews such people years later, 'I don't find anyone, pretty much, who would want to go back to the old situation.'
单选题
What can we learn about Mashco-Piro from the first paragraph?