Performing good deeds may be ingrained

Studies of chimpanzees show their willingness to cooperate


We give up bus seats to the elderly, open the door for pregnant strangers and shovel snow off our neighbors' sidewalks. And the only payoff, it seems, is the warm glow from knowing we've done a good deed.

No other creature cooperates as extensively and effectively as humans often do. Almost none outside Homo sapiens shows signs of being downright altruistic to nonkinfolk. Many scientists think our capacity for self-sacrifice, like our knack for language, helps distinguish our natural history from the rest of the animal kingdom's.

Now two new studies involving chimpanzees support the notion that our collaborative skills are ingrained. They may have already begun to evolve 6 million years ago when chimps and humans split from a common ancestor, researchers said in this week's edition of the journal Science.

"Given the fact that even chimps seem to have some rudimentary forms of altruism, it might make sense to look for evidence that we are biologically prepared to learn such behaviors," said Dr. Felix Warneken, a developmental psychologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and leader of one study.

Charity may seem like an ordinary virtue, but Darwin's view of the natural world as a gladiatorial arena leaves little room for the social graces. As the British zoologist Richard Dawkins wrote in his influential 1976 book, The Selfish Gene, evolution in general appears to favor the self-centered and inconsiderate.

In this view, someone who shares her food is more likely to starve and is therefore less likely to pass on her generosity genes to the next generation. Even modest gestures, such as shoveling a few feet of snow for a neighbor, represent an investment of energy and time that might otherwise be used to advance the personal health, wealth and reproductive prowess of a good Samaritan.

Family sacrifices

Scientists have observed that animals can make great sacrifices for others, but those others are typically close genetic relatives. So, from the perspective of evolutionary biology, selfless behavior toward strangers is something of a conundrum. "It's not so clear why that should happen in an evolutionary framework, but clearly it occurs," Warneken said.

Cooperation for mutual benefit is, perhaps, a stepping stone toward altruism. And many animals learn to work together - wolves, for example, when they are hunting game, and young male dolphins when they are pursuing females.

But primates, such as man's close cousin the chimpanzee, make extensive use of teamwork. In the wild, unrelated males form alliances to defend territory or overthrow existing hierarchies. Allies may share food and grooming sessions, and in zoos, they may even cooperate to escape from their enclosures.

Some biologists wonder whether chimps recognize the strategic value of cooperation over competition, or merely take tactical advantage of situations where other chimps have similar goals.

Intrigued by this question, Alicia P. Melis at the Max Planck Institute and her team studied central African chimps at the Ngamba Island Chimpanzee Sanctuary in Uganda.

Cooperation vs. competition

In one experiment, a chimp was placed in one side of a room divided by a set of bars while two bowls of bananas were set in the other side. The bowls rested on a wooden plank, which was attached to a rope that ran through two rings attached to the board.

The ends of the rope were placed through the bars, but far enough apart so the chimp could not grasp both at the same time. And if the chimp pulled on only one end, the rope would run out through the rings and the board wouldn't budge.

Help, though, was at hand.

Two rooms adjoining the chimp's cage each contained another chimp, a potential ally. All the test subject had to do was lift a wooden peg to summon aid. And that's what happened. Seven of the eight animals figured out quickly that they needed to recruit help.

There were two potential partners, according to Science. A dominant male named Mawa, perhaps predictably, made the worst cooperator. He proved so hopelessly selfish or stupid or both that he either pulled the rope prematurely, unraveling it, or refused to leave his enclosure.

So the chimps learned to call on a second, subordinate animal, Bwambale, who almost always pulled in unison with his partner.

To Melis, the work suggests how cooperation may have evolved among humans, whose social structures - ranging from sports teams to corporations to nation-states - depend on collaborative behavior.

"In this study we were able to demonstrate the logical reasoning that was going through their heads," Melis wrote in an e-mail interview.

What they were thinking, she theorized, is that: "I cannot solve the problem on my own; I need a partner; I'm going to open the door for him; only then will I be able to get the food."

For some scientists, the study helped demonstrate that ostensibly collaborative behavior in the wild could be reproduced in the laboratory.

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