domingo, 9 de septiembre de 2007

Social skills help toddlers outstrip apes in intelligence tests

Apes may be our closest relatives in the animal world, but in the battle of wits human toddlers are walking tall while their hairy ancestors are still dragging their knuckles.

In a study comparing the abilities of two-year-olds with chimpanzees and orang-utans, children surpassed the apes in social learning skills, researchers found. The findings are likely to lend further credence to the theory that higher social ability is a uniquely human trait, setting us apart from other primates.

Some 105 youngsters and 138 apes were subjected to a battery of cognitive tests over a two-week period during the study. The researchers found that the children were far more advanced than the apes in understanding nonverbal communications, copying solutions to a problem and understanding the intentions of others.

Esther Herrmann, of the Max Planck institute for evolutionary anthropology in Leipzig, Germany, who led the study, said: "This is the first time that anything like this has been done. We compared three species to determine which skills and abilities are distinctively human.

"Social cognition skills are critical for learning. Young human children who had been walking and talking for about one year, but who were still several years away from literacy and formal schooling, far outstripped both chimpanzees and orang-utans on tasks of social cognition."

In one learning test, human children and apes were shown how to pop open a plastic tube to get food or a toy contained inside. While the children watched and imitated the solution, the baffled chimps and orang-utans, tried to smash open the tube or yank out the contents with their teeth.

The toddlers were also better at following an adult's gaze and at pointing towards a cup containing a reward.

Human brains are three times bigger than those of the closest primate relatives. The researchers believe the results could provide crucial insight into cognitive evolution since the human and chimp family trees diverged around 6m years ago. Chimpanzees are considered the closest genetic relatives to humans, with orang-utans slightly more distantly related.

The apes, which performed the tests in animal sanctuaries in Africa and Indonesia, were closer to the toddlers in tests measuring "physical cognitive skills" involving things such as quantities, the researchers reported in the study published in the journal Science.

In the same journal, other researchers said they showed that apes and monkeys possessed skills such as guessing the intentions of others.

They studied cotton-top tamarins, rhesus macaques and chimpanzees.

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