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Young Chimp Outscores College Students in Memory Test

Malcolm Ritter in New York
Associated Press
December 3, 2007
 
Japanese researchers pitted young chimpanzees against human adults in two tests of short-term memory, and overall, the chimps won. (See video.)

That challenges the belief of many people, including a number of scientists, that "humans are superior to chimpanzees in all cognitive functions," said researcher Tetsuro Matsuzawa of Kyoto University.

"No one can imagine that chimpanzees—young chimpanzees at the age of five—have a better performance in a memory task than humans," he said in a statement.

Matsuzawa, a pioneer in studying the mental abilities of chimps, said even he was surprised. He and colleague Sana Inoue report the results in Tuesday's issue of the journal Current Biology.

The Tests

One memory test included three five-year-old chimps who were taught the order of Arabic numerals 1 through 9, and a dozen human volunteers.

Participants saw nine numbers displayed on a computer screen. When they touched the first number, the other eight turned into white squares. The test was to touch all these squares in the order of the numbers that used to be there.

Results showed that the chimps, while no more accurate than the people, could do this faster.

One chimp, Ayumu, did the best. Researchers included him and nine college students in a second test.

This time, five numbers flashed on the screen only briefly before they were replaced by white squares. The challenge, again, was to touch these squares in the proper sequence.

When the numbers were displayed for about seven-tenths of a second, Ayumu and the college students were both able to do this correctly about 80 percent of the time.

But when the numbers were displayed for just four-tenths or two-tenths of a second, the chimp was the champ.

The briefer of those times is too short to allow a look around the screen, and in those tests Ayumu still scored about 80 percent, while the humans' scores plunged to 40 percent.

That indicates Ayumu was better at taking in the whole pattern of numbers at a glance, the researchers wrote.

What's Going on Here?

"It's amazing what this chimpanzee is able to do," said Elizabeth Lonsdorf, director of the Lester E. Fisher Center for the Study and Conservation of Apes at the Lincoln Park Zoo in Chicago, Illinois. The center studies the mental abilities of apes, but Lonsdorf didn't participate in the new study.

She admired Ayumu's performance when the numbers flashed only briefly on the screen.

"I just watched the video of that, and I can tell you right now, there's no way I can do it," she said. "It's unbelievable. I can't even get the first two [squares]."

Even with six months of training, three students failed to catch up to the three young chimps, Matsuzawa said in an email.

He thinks two factors gave his chimps the edge. For one thing, he believes human ancestors gave up much of this skill over evolutionary time to make room in the brain for gaining language abilities.

The other factor is the youth of Ayumu and his peers. The memory for images that is needed for the tests resembles a skill found in children, but which dissipates with age.

In fact, the young chimps performed better than older chimps in the new study. (Ayumu's mom did even worse than the college students).

So the next logical step, Lonsdorf said, is to fix up Ayumu with some real competition on these tests: little kids.

Copyright 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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