本文作者：小红猪小分队

Source：http://www.newscientist.com/article/mg21528831.900-warmonger-or-idealist-the-roots-of-human-conflict.html?full=true&print=true

• 25 September 2012 by Dan Jones
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 【Much human violence can be blamed on the instinct to fight for a larger group (Image: Salih Zeki Fazlioglu/AA/Abaca Press/Press Association)】

Homo sapiens is not a particularly violent species – we just have more worth fighting for than other animals

CONSIDER yourself lucky. You are living in the most peaceful era of our species' existence. Today, you are less likely to die at the hands of another person than at any time in human history. So argues Steven Pinker in his monumental history of human violence, The Better Angels of Our Nature. Drawing on a mountain of statistics, Pinker shows that deaths attributable to violent conflicts - from revenge killing and blood feuds to genocides and wars - have been declining for at least the past 6000 years.

This timeframe is too short for the decline to be put down to evolutionary changes. We still have aggressive tendencies but, Pinker argues, human nature has been modified by shifts in culture - changes in politics, law, trade and morality, and an increased cosmopolitanism that has allowed people to vicariously experience and empathise with the suffering of others around the globe.

Despite this, group violence is still a shockingly widespread aspect of human existence. Other animals fight over limited resources and desirable mates, but humans fight for both biological and cultural reasons. We alone will go to war to defend our honour and values. This makes the nature of human conflict particularly tricky to fathom. Nevertheless, we are starting to get a handle on it, and our insights are helping to explain the historical trend away from group violence. They also have practical consequences: researchers are applying them to some of today's most intractable conflicts.

We are not the only species that engages in collective aggression. Wolves in one pack will team up to take out members of a rival group. Our closest relatives, chimpanzees, fight neighbouring troops. Indeed, primatologist Richard Wrangham of Harvard University believes we share with chimps an evolved coalitional psychology that fuels collective attacks. But whereas chimp groups fight to take over territory, our aims are far more complex. "Human aggression is unique in that it can involve conflict over ideas, beliefs and symbols of cultural identity," says Michele Gelfand of the University of Maryland in College Park.

What's more, conflict seems to be an integral part of our social organisation. "We're one species, yet we bind ourselves into exclusive, conflicting groups," says anthropologist Scott Atran of the Jean Nicod Institute in Paris, France. Group hostility and aggression are horribly easy to induce, as social psychologists have long been aware. More than 40 years ago, the late Henri Tajfel showed how people put into teams according to whether they preferred the paintings of Klee or Kandinsky behaved favourably towards team-mates, while treating members of the other team harshly. Since then, numerous experiments have revealed how the flimsiest badges of cultural identity can create hostility towards outsiders - even the colour of randomly assigned shirts can do it.

Paradoxically, these antagonistic tendencies may be intimately linked with another, much more noble side of human nature: our unparalleled capacity for large-scale cooperation and altruistic self-sacrifice. Few activities draw on these traits like fighting on behalf of our group, with the high risk of injury or death that entails. Samuel Bowles, an economist at the Santa Fe Institute, New Mexico, argues that love for one's own group could easily have co-evolved with hostility towards outsiders, creating an unusual mix of kindness and violence. "It's Mother Theresa meets Rambo," he says.

Such a combination would have paid off in a world of warring tribes, where groups with members who were inclined to band together to fight for the common good would have had a competitive edge over groups made up of individuals less willing to pay the ultimate price for their peers. And for much of our prehistory, we lived in such a world. Drawing on archaeological evidence going back 12,000 years and ethnographic studies of tribal societies, Bowles estimates that, on average, 14 per cent of all deaths stemmed from inter-group violence - more than sufficient to promote the evolution of this coalitional psychology (Science, vol 324, p 1293).

If inter-group conflict is in our nature, it is also reinforced by our culture. Culture encourages group members to differentiate themselves from others through markers such as dress codes, food preferences and ritual practices. They also prescribe what is worth fighting over - and some cultures are more antagonistic than others. "We develop social norms about conflict, and because norms differ widely across cultures, there's going to be some big differences in aggressive tendencies," says Gelfand.

One thing that seems particularly relevant is whether a society is individualist or collectivist. This is likely to influence how willing its members are to sacrifice themselves for the group, because in collective societies people's sense of self is more intimately tied up with their group, encouraging them to draw sharp distinctions between those who belong and those who do not.

Gelfand has recently tested this idea. Working with an international team, she carried out a series of structured interviews to explore notions of honour in the US and seven more-collectivist countries - Egypt, Iraq, Jordan, Lebanon, Pakistan, Turkey and the United Arab Emirates. Insults to honour can easily provoke violent retaliation, especially if individuals see their honour as bound up with that of their group. The interviews revealed that these attitudes are less likely to prevail in the US than in the other seven countries, where an individual's sense of honour can encompass a network that often extends beyond family to include clans, tribes, nation and religious groupings (Philosophical Transactions of the Royal Society B, vol 367, p 692). "It's very natural in these cultures to see other members of your group as extensions of yourself," says Gelfand.

A deep commitment to defending group honour is an example of what psychologists call a sacred value. "These are values, usually shared across whole communities, that cannot be traded against material things like food or money," says Jeremy Ginges, a psychologist at The New School, New York. Sacred values are absolute, non-negotiable, and brook no compromise, which is why they loom large in many contemporary conflicts, says Atran.

Atran and Ginges recently found evidence that we think about sacred values in a fundamentally different way to regular preferences. Working with neuroscientist Gregory Berns of Emory University in Atlanta, Georgia, the researchers used fMRI scans to see what happens in the brain as people consider rejecting trivial values and sacred ones. The idea of being bribed to disavow a statement such as "I am a Pepsi drinker" produced activity in brain regions involved in calculating costs and benefits. In contrast, the prospect of selling out on statements such as "I believe in god" or "I am not willing to kill an innocent human being" activated areas that play a role in retrieving rules. This supports the idea that sacred values are processed in the brain as absolute and binding moral commandments (Philosophical Transactions of the Royal Society B, vol 367, p 754).

The role of ritual

Despite the connotations, sacred values need not be religious ones - freedom of speech, liberty, democracy and the ecological stewardship of the planet are treated as sacred by some. Nonetheless, religions, and the rituals they employ, may be important in making values sacred in the first place. Ginges and Atran found that the more time people in the US spent immersed in religious rituals at their church, mosque or temple, the more likely they were to consider both religious and non-religious values as sacred. The perception that your group is under threat enhances this effect, as Ginges and Atran showed in a recent study of Palestinians living in the West Bank (Judgment and Decision Making, vol 7, p 110).

Rituals fuse our sense of self with group membership, says anthropologist Harvey Whitehouse at the University of Oxford, who is running an international study called Ritual, Community and Conflict. One way this happens is through synchronised activities, from liturgical recitation to the goose-stepping of military units. Synchronised physical movements even seem to make people more likely to follow orders to be aggressive to others (Journal of Experimental Social Psychology, vol 48, p 453). Rituals bind groups in other ways too. "I think the most extreme forms of fusion are produced by rituals that produce feelings of shared suffering, pain and fear," says Whitehouse. "At the moment, we're looking at the relationship between intensity of suffering in a ritual and the strength of group cohesion it produces, and what this means in terms of cooperation and self-sacrifice for the group."

It is one thing to identify strongly with a group, quite another to fight for it. Humans are empathic creatures, and we cannot help feeling the pain of others - our brains process it as if it were our own. How do members of warring factions overcome this response? To explore this question, Rebecca Saxe and Emile Bruneau of the Massachusetts Institute of Technology asked Arabs and Israelis to read various stories. In some, a member of their own group suffered physical or emotional pain, and in others misfortune befell people from the other group, or a South American group with which neither had a grievance. Arabs and Israelis reported feeling equal amounts of compassion for their own people and the South Americans, and less for each other. But results from brain imaging were much more unexpected. Regions implicated in thinking about the emotional states of others were equally active when Arabs and Israelis thought about each other's suffering as when the victim was a member of their own group. What is going on?

Bruneau believes that suffering is so salient in the conflict between Arabs and Israelis that their brains register it strongly. But that doesn't mean they empathise with one another. "The full-blown neural response of empathy has a number of steps," he says. "The first is simply recognising that another person is suffering, and that's what we're picking up in these studies." How people respond to this awareness is another matter. "You might think they deserve to suffer, and feel glee. You could feel distressed and be motivated to help them. Or you could be indifferent." Here, combatants can generate an empathy gap to detach themselves from the suffering of an enemy.

This empathy gap can be reduced, however. Saxe and Bruneau found that people were far more likely to feel empathy when they had been told something about an enemy's life story. A similar rationale underpins the use of dialogue in conflict resolution. "The idea behind these programmes is that if you can take the perspective of a member of the other side, it will improve your attitudes towards that other group as a whole," says Bruneau.

However, he and Saxe suspect this doesn't apply when there is an asymmetry of power. Members of dominant groups may feel more empathic when listening to the perspectives of the dominated, but for less empowered groups it is more important that they have a chance to get their perspective heard. So far they have found support for this idea in dialogues involving white US citizens and Hispanic immigrants in Arizona, as well as between Palestinians and Israelis.

Promoting peace

Even simple changes to our perception of others may help promote peace. Psychologist Carol Dweck of Stanford University in California recently led a series of studies showing that we are more likely to harbour negative attitudes towards other groups when we believe them to be incapable of change. Good news comes from her studies with Israelis and Palestinians, which demonstrate that people can be induced to see the other side as more flexible. This not only leads to more positive attitudes towards one another, but also makes individuals more willing to compromise for peace (Science, vol 333, p 1767).

Also in the Middle East, Atran and Ginges found that offering financial incentives to compromise on sacred values frequently backfires, leading to moral outrage and even stronger rejection of an offer. However, people were more willing to compromise if their opponents recognised their sacred values and made symbolic gestures to atone for past wrongs. In a survey involving thousands of respondents, many Palestinians said they would consider recognising the right of Israel to exist if Israel offered an official apology for the suffering of Palestinians in the 1948 war. And Israelis would be more likely to accept a return to pre-1967 borders if Hamas explicitly renounced previous anti-Jewish statements and recognised Israel's right to exist (Proceedings of the National Academy of Sciences, vol 104, p 7357). Israeli prime minister Benjamin Netanyahu and Hamas leader Khaled Meshal hold similar views, says Atran, who has spoken with both of them.

What are the prospects for humanity? We have already become more peaceable through cultural change, including the development of impartial legal systems and enlightened attitudes towards slavery, women and minorities. As Pinker puts it, such developments have reined in the inner demons that push us to violence, while allowing the better angels of our nature to flourish. A fuller understanding of coalitional psychology and the values we hold dear should help us quell those demons further.

Bruneau, for one, is confident, having spent time in conflict zones such as Northern Ireland and South Africa. "I know individuals can change, and I've felt change within myself. That's what gives me optimism."

Dan Jones is a writer based in Brighton, UK