8.07.2004

Return to the Planet of the Apes?
SIGN of high IQ? Chimps yawn like humans


INUYAMA, Aichi Prefecture-Monkey see, monkey yawn.

That's right, adult chimpanzees yawn right after seeing others yawn, just like adult humans, according to research conducted mainly by the Primate Research Institute of Kyoto University.

The study will be a useful tool for deciphering the evolution of emotion, the researchers say.

``The `transmission' of yawning requires considerably high intelligence,'' says Tetsuro Matsuzawa, professor of comparative cognition at the institute.

``It does not occur without an ability to distinguish oneself from others and a sort of sympathy toward the behavior of others. The study proved that the intelligence of chimpanzees is high enough for the transmission,'' he said.

Researchers, including Matsuzawa and James Anderson, professor of psychology at the University of Stirling in Britain, studied nine chimps at the institute, including three young chimps and six aged 19 or older. Among the older chimps were Ai, known for her ability to recognize words and numbers, and Mari.

The team showed the chimps a videotape of chimps yawning about 10 times, and another tape of chimps just opening their mouths, each for 3 minutes. The team observed the chimps while the tapes played and for 3 minutes after.

They found that the six older chimps yawned 10 times on average when the tape showed yawning chimps. Their yawning averaged only 4.7 times when they saw the other tape.

The ``transmission'' of yawning was especially high for Ai and Mari. Ai yawned 24 times and Mari 25 times during and after the ``yawning'' tape.

But yawning does not transmit to young chimps-the same result as for human children. All three chimps aged 3 did not yawn once.

Source: Asahi.com


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