Unthinkable_ Who Survives When Disaster Strikes - and Why - Amanda Ripley [66]
Why do chimps band together? For one thing, de Waal says, the show of affection might intimidate the enemy. If the predator wants one of them, he will have to deal with all of them. Companionship also calms the chimps, making them better able to handle the stress of the threat. The same is true in humans. In laboratory experiments, people who are asked to complete tasks with a friend at their side exhibit lower heart and blood pressure rates than when they go through the tasks alone.
Even before a challenge materializes, camaraderie has clear benefits. In the early 1980s, primatologist Carel van Schaik went to Indonesia to try to understand monkey groups. Van Schaik studied two communities of long-tailed macaques—one on the island of Simeulue, a blissful macaque paradise with no cat predators, and one in Sumatra, a far scarier place populated by tigers, golden cats, and clouded leopards. After watching both communities, van Schaik found a significant difference. On Sumatra, where there were more predators, the macaques traveled in much larger groups. The bigger the threat, in other words, the bigger the posse—and the more eyes, ears, and nostrils with which to detect a predator. On Simeulue, the monkeys traveled in very small groups—the smallest groups of virtually any macaque community ever studied. They simply didn’t need one another the way the Sumatra macaques did.
Even lower-order animals band together in times of danger. Fish cluster in tight schools, and birds call to each other to warn of an approaching hawk. But they don’t do it to be nice. As evolutionary biologist Richard Dawkins has noted, “Anything that has evolved by natural selection should be selfish.” We help one another because we get benefits from doing so, if not immediately and directly, then eventually or indirectly. Evolutionary biologists call this “reciprocity.” And, in evolutionary terms, it means that an animal does something to improve its odds of passing on its genes—either by reproducing or by protecting its relatives.
If I carry Lou Lesce’s briefcase down the stairs of the World Trade Center, I might not get anything tangible in exchange, but I might still get something. “Evolutionary biology has a hypothesis to account for small conspicuous acts of kindness,” says animal behavior expert John Alcock. “My guess is that the people who assisted others in the World Trade Center knew that others were observing. They were not calculating, but their desire to commit some nice act—commiserating, directing, guiding others to safety, might have had a substantial payoff in terms of improved reputation.” There may have also been something calming about helping others that day; it lent a sense of normalcy and orderliness to the abnormal and disorderly.
Until about a fraction of a second ago, in terms of human history, we lived in small, extended-family bands. We all knew one another, from birth to death. So by aiding one another, we could build a reputation for being generous and helpful, which would encourage others to cooperate with us—which would in turn boost our chances of reproductive success. “I know this sounds cold and analytical to the average layperson,” says Alcock. “I’m not saying that people who do this are not motivated by impulses that are moral, ethical, and desirable. I’m saying that it’s precisely because these impulses are adaptive that we admire them as moral and ethical.”
Sometimes what looks like altruism is actually quite the opposite. In an elegant paper published in 1971, biologist W.D. Hamilton described what he called the “geometry for the selfish herd.” When a dog runs after a herd of sheep, the sheep at the back of the pack will butt or jump his way into the ranks ahead of him—leading the herd to become more and more tightly packed together. From afar, it may appear that the sheep are banding together in a grand show of unity. In fact, each is just trying to avoid being eaten, by reducing his “domain of danger,” as Hamilton puts it. The animals on the edge of the herd are the easiest to pick off. So no one wants