Monday, March 06, 2006

Altruism, Cooperation, and Primates

The Grave Digger
German researchers have published in Science a discovery that infants as young as 18 months show altruistic behavior. Toddlers help strangers with a range of tasks, from stacking books to picking up pegs, suggesting that humans have a natural tendency to be helpful.

What is surprising is that young chimps displayed similar behavior. Young chimps did the same, providing the first direct evidence of altruism in non-human primates. The scientists posit that altruism may have evolved six million years ago in the common ancestor of chimps and humans.

"This is the first experiment showing altruistic helping towards goals in any non-human primate," said Felix Warneken, a psychologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

"It's been claimed chimpanzees act mainly for their own ends; but in our experiment, there was no reward and they still helped."

Link. Nearly all of the group of 24 18-month-olds helped, usually in the first 10 seconds of the experiment. However, the researchers noted that the children only did this if they believed the dropping was accidental. If the object was thrown down deliberately, the children did not retrieve it.

The tasks were repeated with three young chimpanzees that had been raised in captivity. The chimps did not help in more complex tasks[...], but did assist the human looking after them in simple tasks such as reaching for a lost object.

"Children and chimpanzees are both willing to help, but they appear to differ in their ability to interpret the other's need for help in different situations," the two researchers write in Science.

Furthermore, chimpanzees appear to display the most complex understanding cooperation in nonhuman animals. A study by Alicia Melis at the Ngamba Island Chimpanzee Sanctuary in Uganda indicated that chimps recognized when collaboration was necessary and chose the best partner to work with.

The chimps had to cooperate in reaching a food tray by pulling two ends of a rope at the same time.
[...]
But she said there was still no evidence that chimpanzees communicated with each other about a common goal like children do from an early age.

This seems to complicate our understanding of cooperation in light of an earlier study published in Nature in which captive chimpanzees failed to help others in their social group, even when it caused no inconvenience.

A team led by Joan Silk of the University of California, Los Angeles (UCLA), set captive chimpanzees tests in which they obtained a food reward.

The chimps were presented with two reward options. One option allowed a chimp only to serve itself with food. The other secured the same reward, but also delivered food to another chimpanzee in an enclosure next door.

Dr Silk's team found the 29 chimps tested in the study were no more likely to pick the second option than the first, even though it allowed them to do a "good deed" at no cost to themselves.
While the chimps were unrelated, they had been living together in the same group for 15 years and might have been expected to be very close. As food sharing has been demonstrated in groups of wild chimpanzees, some of the lack of cooperation could be due to captivity.

So really what I see here is Science contradicting Nature... I sense an epic battle only comparable to determinism vs. free will. Who will win? We may never know.

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