A meeting of the minds Monkeys: An animal psychologist is studying capuchins to understand how human infants and children learn.

November 17, 1996|By Dennis O'Brien | Dennis O'Brien,SUN STAFF

Gregory Westergaard tries to figure out what goes on inside a monkey's head.

The animal psychologist has spent five years watching monkeys soak up apple juice with leaves, hit targets with stones, crack walnuts with rocks and shatter rocks to create knifelike wedges to cut into jars of peanut butter.

"They have this highly charged manipulative drive," Westergaard said by a cage teeming with 18 monkeys near his office at the National Institutes of Health Animal Center in Poolesville. "You can look in their eyes and see there's something going on in there."

Understand a monkey's mental capacity and you start to understand the human learning process.

Roger Birkel, director of the Baltimore Zoo, said Westergaard's work also might help zoo directors figure out better ways to keep monkeys challenged and entertained.

"Part of our challenge at the zoo is to give animals opportunities to keep them challenged. Keepers are always looking for ways to enrich the animals lives, and if this scientist's studies can help, it would be wonderful," Birkel said.

Westergaard has been feeding, filming and watching 45 black-capped capuchin monkeys at the animal center in western Montgomery County since 1991.

Westergaard, who has written 40 articles about his subjects, works with capuchins because, along with chimpanzees, they are considered the animal kingdom's most proficient tool-makers.

Scientists attribute the monkey's abilities to their nimble hands.

"Different monkeys have very different kinds of hands," said Birkel, a monkey expert who has studied black lemurs in Madagascar. "Different monkeys are adapted for different skills."

The gibbon, for instance, has a very small thumb because a full-sized one would get in the way of swinging from trees, Birkel said.

Capuchins, by contrast, are foragers that gather food from the jungle floors of Central and South America. They need their thumbs.

"They'll tear things apart, break open a plant or a root to get at what's inside. That's where they get these tool making abilities," Westergaard said.

Westergaard's favorite is Morris, a feisty 2-year-old capuchin with a taste for peanut butter.

Like a proud parent, Westergaard showed a videotape of Morris to visitors who had been allowed past the gated security booth and into the animal center.

The tape showed Morris smashing a quartzite stone so that he can use one of the jagged fragments as a tool to cut into a plastic jar of peanut butter.

"Look, watch this," said Westergaard, reversing and fast-forwarding the tape to replay the highlights of Morris' getting into the sealed jar.

It would be easier if Westergaard unscrewed the cap, but the point, he said, is not to make it easy but "to see the strategies that he adopts to solve this particular problem."

Westergaard, a Kensington resident, began studying monkeys in 1982, when he was majoring in psychology at San Diego State University. While working for a professor studying a colony of 14 capuchins, Westergaard handed a plastic laundry scoop to a 6-year-old monkey and watched as the primate used it as a cup to drink water.

He then gave another one a funnel and watched, fascinated, as the 10-month-old monkey plugged the bottom of the funnel with her finger and began using it as a cup.

"They truly understood the concept of a cup and how to fix a cup that didn't work well," said Westergaard, a Los Angeles native.

Westergaard, 36, who has a doctorate in child development from the University of Washington, said he wants scientists to better understand primates but also hopes his work will help psychologists better understand how human infants and young children learn.

Behavioral differences between children and capuchins begin to show up dramatically at the age of about 2, about the time that children begin to talk, he said.

"Capuchins go through the same development process as humans in the very early stages of life. They exhibit humanlike behavior, like using tools," Westergaard said. "By understanding them, we may be able to figure out how we develop."

Pub Date: 11/17/96

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