Correction to This Article
With a Science article in some March 19 editions, captions for photographs of a warbler and a cowbird were reversed.

Behavior May Suggest We're Not Only Human

[Photo of a female cowbird]
Female cowbirds parasitize the nests of smaller songbirds and will damage the eggs of birds that resist. (Photo courtesy of Chris Young)
By Shankar Vedantam
Washington Post Staff Writer
Monday, March 19, 2007

When Emory University primatologist Frans de Waal read a news story that said Microsoft's chief executive, Steve Ballmer, had hurled a chair across the room on hearing an employee was going to work for rival Google, the scientist immediately made a connection with his own research: "When I see such behavior, I think of a chimpanzee."

Another time, a researcher that de Waal knew told him that whenever she chatted with another scientist in the hallway, her boss would get upset. He would later drop by her office and tell her she ought to stay clear of that person.

"He was constantly interfering whenever she had a contact with an important person," de Waal said. "Chimpanzees also divide and rule. You have an alpha male, and he will try to keep his supporters away from his rivals. His supporters are in trouble if they groom one of his rivals."

Does such behavior make you laugh? Well, if de Waal and other scientists are right, you may have to address some of your mirth to that face in the mirror.

Over the past two centuries, people have had to disabuse themselves about various ideologies asserting that humans are fundamentally different from other animals. Biologists have shown that our arms and legs and organs have long evolutionary histories. Beliefs about the uniqueness of human behavior might well be the last bastion of our superiority complex, but research by de Waal and many others suggests that even this redoubt may be crumbling.

"I have done studies of reconciliation and coalition strategies in chimpanzees," de Waal said. "Business managers tell me that reminds them so much of what people do."

The idea that human behavior -- not just our physical bodies -- may have long evolutionary antecedents raises complicated questions about human agency and about how much of what we do and think is hard-wired. It is one thing to say we have eyes because our ancestors had eyes, but should we also credit our evolutionary predecessors for our highly complex social and political arrangements?

Scientists such as de Waal argue the research suggests that, much as people believe in the originality of their thoughts, a lot of human cognition probably takes place at an automatic level, guided by inborn tendencies. About the woman with the possessive boss, for example, de Waal said: "I am sure her boss is not consciously doing that. It just bothers him if she has a chat with a rival."

Two recent studies from the world of birds give us a glimpse into how far back in evolutionary terms complex behaviors that we would normally associate with humans go. One of these behaviors has a nice altruistic aspect to it. The other, not so much. But more on the morality question later.

Emily DuVal, a biologist at the Max Planck Institute for Ornithology in Germany, found that male lance-tailed manakins display the behavior seen at nightclubs, where a person plays "wingman" or "wingwoman" to help a friend impress a potential mate.

In a study of 457 lance-tailed manakins in Panama, DuVal found repeated instances of two males performing a skilled dance for the benefit of a female bird who was watching. The group performance, however, helped only one of the birds -- the alpha male. If only one lance-tailed manakin got to mate, why did the other bird, the beta male, cooperate in the dancing ritual when he had nothing to gain?

In a paper she published in the April issue of the American Naturalist, DuVal found there is evidence that good "wingbirds" are more likely than other birds to become alpha males themselves. What makes the behavior especially interesting is that one lance-tailed manakin might be helping another because some other bird will help the helper down the road. Such behavior suggests an intricate social system where investments pay off in the distant future.

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