Why We Take Risks

When it comes to evolution, survival of the fittest is only half the story. The handicap principle holds that humans make showy and sometimes dangerous displays of courage to increase their status and attract mates

By Richard Conniff, Elinor Carucci|Saturday, December 01, 2001
RELATED TAGS: SEX & REPRODUCTION


Two thirds of the way into his August 1998 attempt to fly round the world by balloon, Steve Fossett ran into a thunderstorm at 29,000 feet above the Coral Sea and began to plunge uncontrollably as wind and hail whipped his ruptured balloon. At 4,000 feet, he climbed through the hatch atop his capsule and cut away the fuel and oxygen tanks to slow the descent. Then he lay down on a bench to distribute the impending impact across his back. "I'm going to die," he said out loud.

I'd met Fossett the year before, and he was mild and Midwestern, a multimillionaire with no particular need for publicity. Now he was falling out of the sky in a broken balloon. Why? For that matter, why did another American businessman recently pay $20 million to get himself launched into space on a Russian rocket? Why do ordinary people climb Mount Everest?

Risky behavior might seem like just a quirk of the oddly named species Homo sapiens, except that a taste for grandstanding is common in the natural world too. For instance, antelope pursued by hungry cheetahs often leap acrobatically straight into the air, a practice called stotting. Common sense says they should be sprinting straight for the far horizon. Even lowly guppies dance right under a predator's nose before darting away. Why do humans and animals alike do such dumb stuff? Stuff that is unnecessary, flamboyant, and often downright deadly?

In search of answers, I found myself at five o'clock one recent morning rattling across an Israeli desert in a dusty little Peugeot with Amotz Zahavi, the 73-year-old b?te noire of the biological world. "This is a minefield," Zahavi said, indicating a fenced-off area just to our left. He veered right, both hands on the wheel, down into a wadi, or dry riverbed. "So we won't go there." We were looking for Arabian babblers, birds he has been studying for 30 years at the Hatzeva Field Station near the Jordanian border. The babblers, when we found the first group a few minutes later, were brownish, forward-leaning birds, about the size of mockingbirds, with long tails and sleek heads. Unflamboyant. Not, at first glance, worth the trip. But Zahavi introduced them as old friends, with names corresponding to the letters on their ankle bands: Pusht (PVST), Taxas (TXXS), Tasha-Sham (TSSM), and so on. The birds also knew Zahavi. They gathered at his feet and cocked one eye up, waiting for him to toss a bread crumb or the occasional mealy worm.

As Zahavi fed them, he rattled off individual stories out of a Middle Eastern melodrama: A brother killed in a trap three months ago, a mother forced to become a refugee, an exiled stepsister, Zatash (ZTAS), who'd returned and pushed her way back into the group. He knew the birds better than most people know their human neighbors, better perhaps than the birds knew themselves. "Go and copulate, lady," he commanded at one point, a little vexed with one coy babbler. No aspect of their lives was too trivial for Zahavi to mull over. "You sit here in the desert and say, 'Why is it like this and not like that?'" he remarked as we huddled under an acacia one evening waiting for a group of babblers to come to roost. "Being alone in the desert, all these things creep in sooner or later."

One of the things that crept in during the early years of his research was the far-ranging and controversial idea for which he is best known. Zahavi's handicap principle attempts to explain why babblers risk their lives by yelling at predators, why peacocks carry splendid but cumbersome tails twice the length of their bodies, and even perhaps why Ted Turner gave $1 billion to the United Nations. Zahavi's handicap principle holds that animals and humans alike prosper not in spite of our riskiest and most extravagant behaviors but because of them. These behaviors are the way we advertise how prosperous, how fit, how fearless we are. And because the world is a jaded, cynical place, we have to incorporate a significant cost, or handicap, in our advertising to make it persuasive. Thus antelopes really are indulging in a dangerous waste of energy when they stot in front of a cheetah. But their willingness to risk it is how they tell the cheetah: "Don't even bother trying."


"I don't believe there is anything in nature that is trivial," says Israeli biologist Amotz Zahavi, whose observations of babbler birds led him to develop the handicap principle. "I see a twitch in the eye. I see a ruffle in the feathers. I have a sort of intuition about what is going on."
Photograph Santiago Lyon/AP
Comment on this article
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT
ADVERTISEMENT
Collapse bottom bar
DSCJulyAugCover