Chimp to Chimp

Those garrulous primates

The two youngsters, ages 4 1/2 and 3 1/2, are perched on stools before a large console with pushbuttons, doing their lessons. For a while they peck busily away at the keys. But like playful kids everywhere, they eventually become bored and mischievous. Ignoring their work, they start to hug, squeal and make faces at each other, wrestle a littie and bound merrily about the room.

Rambunctious students in a computer-age kindergarten? Well, sort of. The students, named Sherman and Austin, are chimpanzees, enrolled in an extraordinary class at the Yerkes Regional Primate Research Center in Atlanta. Despite their occasional unruly conduct, they are being successfully taught to "talk" to each other in a language other than their own usual mix of sounds and gestures. That may be a scientific first, say their instructors, who are led by a husband-wife team of psychologists, Yerkes' Sue Savage-Rumbaugh and Georgia State University's Duane Rumbaugh.

For the past few years, researchers have become increasingly skilled at opening dialogues with chimpanzees, perhaps man's closest kin in the animal world. The famed chimp Washoe, now in Oklahoma, has managed to learn more than 100 hand sign-language symbols since the mid-'60s. At Yerkes, a sprightly female named Lana was tutored to communicate with her keepers in a language called Yerkish--a system of geometric symbols (squares, circles, lines, etc.) that stand for English words. By punching out these symbols, or lexigrams, as they are called, on a computer-monitored console, which displayed them on an overhead screen, Lana became skilled enough in Yerkish to say things like "Please machine give Lana juice." But not until now have such human-designed symbols been used by one chimp to "converse" with another.

Like Lana, Sherman and Austin first had to be introduced to Yerkish. Encouraged by praise and rewards of food, they soon learned the lexigrams for different foods and could identify foods by hitting the right buttons on their console. But could they be taught to exchange such information as well?

In one test, the researchers report in Science, they alternately led each chimp off by himself into another room. There he was allowed to watch a container being filled with any one of eleven different kinds of food, such as bananas, bean cake and candy. Handed the food, he was then led back by a researcher (who did not know the container's contents). The other chimp quickly eyed the sealed container but had no idea what was in it either. The returning chimp would then press the appropriate button on the console, which would flash the lexigram for the food on the screen. If the other chimp understood and identified what he saw by also pressing the correct button, both chimps would be rewarded with the food. In one series of trials, Sherman and Austin got the message (and the snack) across to each other 60 out of 62 times.

But could the animals communicate directly on the console without human participation? To find out, the scientists separated the chimps by a transparent barrier with a small opening in it. Only one chimp was given food, but the other chimp could see the varied delicacies. Spontaneously, without any prodding by the investigators, he would punch out his request and, more often than not, his buddy would comply. At first Sherman, older and apparently more quick-witted, seemed to make "errors." When asked to share an especially tasty item--say, chocolate--he occasionally ignored the request, seemed to feign ignorance or proffered something less desirable.

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