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Primate Researchers Probe Mind of Another Species

Mind: Students of animal cognition are discarding the notion that humans are the only thinking beings.


INUYAMA, Japan — Ai nibbles a bit of apple as she hunches over the computer, rapping one big knuckle against the screen again and again, barely looking at her selections.

The chimpanzee is doing what a preschooler can do: She's matching colors and Japanese characters, matching designs and colors, counting, remembering strings of numbers. Hold up two red pens, and she'll touch the signs for red and pen and two.

Nature and nurture have combined to make Ai one of an elite group. Her cognitive abilities have been chronicled in the science journal Nature. She is part of the discussion of animal cognition: Who thinks? How? Why? And so what?

The research goes far beyond chimps and other apes, to parrots and scrub jays, spiky little echidnas, sea lions.

"There's almost no question that some animals can do what we would call thinking if people were doing it," said Darren Burke, a lecturer at the University of Wollongong in Australia who studies psychology across species.

That includes Ai. She's a prodigy, and she knows it: She's fast and she's casual, tapping the screen to put scattered numbers in order, or linking words.

Ai, named after a comic-strip character whose name means "love," is in good company. There's Koko the gorilla, said to know American Sign Language and understand English. Kanzi the chimp, who learned to link symbols with spoken English words from the training given his mother. Sue Savage-Rumbaugh's chimps, communicating through symbols on a keyboard.

Peering in at other members of the animal kingdom will tell us more about ourselves, scientists hope.

"To me, it's hard to understand humans from research on humans," said Nobuyuki Kawai, a researcher at Kyoto University's Primate Research Institute.

Kawai works with Ai from an office stuffed with pictures of primates, from Curious George to soulful photographic portraits of his associates, the chimps here.

Ai, in one recently reported experiment, showed she can remember the correct sequence of five random numbers, performing about as well as an average preschooler.

When she touches the first number on the computer screen, the other four disappear behind small white squares. She then touches the squares in numerical order, succeeding better than 90% of the time in identifying four numbers and about 65% of the time with five--far better than chance.

She's remembering where on the screen the figures lie, demonstrating short-term memory, an ability crucial to daily life and to overall cognitive ability.

Without it, directed action is impossible. "You cannot write down what you just heard," Kawai said.

The Kyoto researchers, led by Tetsuro Matsuzawa, wonder if Ai might share her skills with any offspring.

Nearing chimp middle age at 23, Ai gave birth to a male baby on April 24 that was conceived through artificial insemination. She had given birth to a stillborn baby in 1998.

At 130 pounds, Ai is the size of a woman, with wide brown eyes and a sheen of silver on her back.

Different kinds of animals have developed different parts of the brain, or different aspects of intelligence, depending on the evolutionary pressures they faced.

Birds like nutcrackers have terrific spatial memory, for example. It means they can remember in snowy February where they cached all those nuts in sunny September.

Primates and dolphins, on the other hand, live in complicated social groups, and their sort of intelligence grew from the need to understand relationships.

Other sorts of thinking processes include allocating attention, numerical ability and language skills--possibly the most controversial idea involving nonhuman abilities.

"The challenges are to figure out where humans and animals are similar as well as different, and then figure out why," said Marc Hauser of Harvard University.

Individual animals display different abilities, just like humans.

"Ai has shown to be one of the smartest apes in the world," said Frans de Waal of the Yerkes Regional Primate Research Center at Emory University in Atlanta.

Other chimps display much more sophisticated and complex tool use. Some are better at listening, or at tracing the lines that make letters on the computer screen.

Researchers at the institute, with its 11 chimpanzees, hope to find in them yet more cognitive abilities comparable to humans.

The Inuyama team is trying "to demonstrate capacities that we barely knew apes possessed," de Waal said. "It is truly groundbreaking research."

Greater linguistic ability? Proficiency in mathematical division? Maybe so.

"Before [Jane] Goodall's discoveries, we thought tool use was unique to humans," Kawai pointed out. "Now we know other primates use tools too."

The distinction between people and beasts used to be the difference between learning and thinking, between reacting to a stimulus and knowing the result ahead of time.

"Now there's good evidence that the rat presses the bar because it knows that when it presses the bar it gets food," Burke said.

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