Shadows of Forgotten Ancestors (52 page)

This work has in turn been criticized. Chimps require close emotional ties for social tasks and, one would think, especially for something as difficult as language; instead, Nim had sixty different trainers over a four-year period. There is a tension between a loving, one-on-one environment that might be needed to teach language skills and the emotionally sterile protocols needed so that scientific results are, with high reliability, uncontaminated by the enthusiasm of the experimenters. It has frequently been found that apes sign most creatively in spontaneous circumstances in their everyday life, and not in experimental sessions. Too, there was great emphasis on drill in the Nim experiments, the very opposite of spontaneity. The complaint about Nim interrupting the signing of his trainer has itself been belittled, because Ameslan speakers may sign simultaneously without stepping on each other’s lines, an advantage of signing over speech. Delayed imitation is just what human children do when they first learn language. For all these reasons, just how much grammatical dexterity apes have is still an open question.
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But clearly chimps can use something like the rudiments of language with much greater facility than had been thought possible before the experiments of the Gardners. They can unambiguously associate certain signs with certain people, animals, or objects—unsurprising
when there are
monkeys
with different alarm cries and evasion strategies for different species of predators. Chimps have mastered an elementary vocabulary of a few hundred words, comparable to what a normal human two-year-old can do. Chimps who have some knowledge of these signs and who are raised together have been known spontaneously to sign to one another. There is at least one case in which a young chimp, uninstructed by any human, is said to have learned dozens of signs from another chimp knowledgeable in Ameslan.
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“We may consider it proven,” said the psychologist William James, “that the most elementary single difference between the human mind and that of brutes lies in this deficiency on the brute’s part to associate ideas by similarity.” He held this to be a more fundamental cause of human uniqueness than reason, language, and laughter—all of which, he taught, emerge from recognizing similarities among ideas.
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Some chimps were taught a common symbol to describe any one of three foods, and another to describe any one of three tools. Then they were taught the individual names of other foods and other tools and asked to put them in the proper categories—not the new foodstuffs or tools themselves, but the arbitrary
names
of the new foodstuffs and tools. They did exceptionally well.
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How is this possible, unless chimps reason, form abstract ideas, and “associate ideas by similarity”? Another domesticated chimp, Viki Hayes, was given two piles of pictures, one of humans, the other of nonhumans, and then handed a stack of additional pictures and invited to categorize. Her performance was perfect, with one small exception: She placed the picture of herself among the humans.

The psychologist Sue Savage-Rumbaugh
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and her colleagues devised a keyboard with 256 lexigrams on its two sides. Each lexigram stands for something of interest to a chimp—“tickle,” “chase,” “juice,” “ball,” “bug,” “blueberry,” “banana,” “outdoors,” “videotape,” and so on. The lexigrams do not depict their referent; rather, they show geometrical or abstract figures that only by arbitrary convention are connected with what they stand for. The scientists tried to teach this lexigraphic language to an adult bonobo, but she was an indifferent student. Her six-month-old son, Kanzi, often accompanied his mother to these training sessions and was mainly ignored by the scientists. Two years later, having observed the laboratory routine in depth but
never having been trained (for example, by being given a banana for typing the banana lexigram), Kanzi demonstrated that he was learning what they were trying to teach his mother. (His interest eventually became hard to miss: He would leap on her hand, her head, or the keyboard at the moment she was about to select a lexigram.) The focus of the study switched to him.

By age four he had mastered the board, and would routinely use lexigrams to request, confirm, imitate, choose an alternative, express an emotion, or just comment. He would indicate a future course of action and then do it. In combining two action lexigrams, he would predict (or better, reveal) the impending sequence of events; if he typed “chase, tickle” he would chase and then tickle the experimenter or another chimp, and only very rarely tickle before chasing. Kanzi typed “hide peanut,” and then did just that. It seems hard to deny that Kanzi has a mental image of his intended future actions, and in appropriate sequence. As time went on, he developed other grammatical rules, especially putting the action before the object, rather than vice versa (“bite tomato,” rather than “tomato bite”). Inventing grammar is much more impressive than merely being taught it.

Still, after some years about 90% of Kanzi’s utterances were only a single symbol;
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rarely did they comprise more than two symbols. This is the same pattern found for Nim. Perhaps we are coming up against some fundamental limitations in chimp capacity for language.

Kanzi has shown, again via an accidental discovery, that he can understand hundreds of words of
spoken
English. Place earphones on his head, situate yourself in another room, make a request of him through a microphone, and the video camera reveals him doing what he is asked. Done this way, no gestural cues can be unconsciously communicated from human to ape. Typical of over 600 novel requests, perfectly complied with, were “Put the backpack in the car,” “Do you see the rock?… Can you put it in the hat?” “Take the mushrooms outdoors,” “Knife the orange,” “Eat the tomato,” and “I want Kanzi to grab Rose.” Even some of Kanzi’s errors are not so bad. Asked “Can you put the rubber band on your foot?” he promptly put it on his head.
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His performance was comparable to that of a 2½-year-old
human who was tested in the same set of experiments. Other bonobos are also found to understand spoken English.

Kanzi loves to play ball. Hide a ball in one of seven designated sites in the laboratory’s fifty-five-acre forest, tell him by lexigram or spoken word where the ball is, and Kanzi with high accuracy makes for the site, searches, and finds the ball.
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In this case there is a reward for understanding spoken English. But in most cases Kanzi receives no reward except the approval of humans and perhaps some gratifying sense of the power of communication. The motives of a young child learning language may not be very different.

In a different laboratory, a chimp named Sarah was able to recognize that red characterized an apple more than green did (she had not been exposed to the Granny Smith variety), and a square with a stem was a better representation of an apple than a square without a stem. She was also able to associate the
words
for each of these properties of an apple with the
word
for apple—and these words were not in Ameslan, but in a symbolic language of plastic tokens she had been taught, the tokens not resembling the objects in question.
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(“Apple,” for example, was represented by a small blue triangle.) How is this possible, unless chimps are able to abstract and categorize?

Other experiments have shown chimps capable of reasoning by analogy and by transitive inference, described by the discoverers of this aspect of chimp thought as “ ‘A r B, B r C, therefore A r C,’ where r is some transitive relation, such as greater than.”
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(There may, for all we know, be critics who do not even understand the preceding sentence but who deny that chimps reason.) Still other experiments have been interpreted as showing that chimpanzees impute states of mind to others, or, as the psychologists David Premack and G. Woodruff put it, that chimps have “a theory of mind.”
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Where chimps are linguistically deficient, at least so far, is in grammar and syntax. They are bereft of subordinate clauses, articles and prepositions, tenses, conjugation of verbs, and the like—as are small humans first learning language. The absence of such grammatical machinery prevents the lucid expression of even fairly simple ideas; misunderstandings tend to accumulate. Compounded by small vocabularies, it’s a little like a middle-aged American, relying on barely remembered high-school French, attempting to be understood in rural Provence. A better analogy might be the “pidgin” languages that
emerge at the interface between two or more fully realized but very different human languages; despite their linguistic facility, the speakers revert to something like chimpish. Oddly, no one has made a serious and systematic effort to teach apes grammar and syntax,
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so we can’t be sure it’s beyond their reach. “Until then,” writes a modern linguist, “one cannot entirely close off the possibility, unlikely as it may be, that apes could acquire language in its fullest sense.”
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Savage-Rumbaugh and her co-workers toy with the possibility that chimps and bonobos exhibit impressive facilities to learn something of human languages because they have their own languages, vocal or gestural, that we have not yet deciphered.
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In announcing the location of prey, or predators, or a hostile patrol, rudimentary language would be strongly favored by natural selection. Long before humans and chimps went their separate ways, considerable aptitudes for thought, invention, and language were probably percolating in our primate ancestors.

But partly because of Terrace’s work, and partly because of the perceived difficulty of doing clean, controlled, non-anecdotal experiments on so emotional a being as a chimpanzee, financial support for many of these studies has nearly disappeared. In one case, the colony where apes had been taught Ameslan had fallen on hard times. Years had passed. Support was drying up. No one seemed interested in conversing with the chimps anymore. The grounds had become weedy and overgrown. The inmates were about to be shipped to laboratories for medical experimentation. Before the end, they were visited by two people who had known them in the old days. “What do you want?” the visitors asked in Ameslan. “Key,” two chimps are said to have signed back from behind bars, one after the other. “Key.” They wanted out. They wanted to escape. Their request was not granted.
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When chimps approach sexual maturity, their behavior changes. Both sexes are then much stronger than humans and given to occasional, unpredictable bouts of rambunctiousness and violence. So as the chimps get older, almost inevitably the experimenters find themselves driven to use steel cages, collars, leashes, and electric cattle prods. The chimps must feel, bit by bit, betrayed by the humans and less
inclined to cooperate in their strange language games. Accordingly, back in the days when the research was generously supported, it was thought prudent to terminate experiments on teaching chimps language—requiring, as it does, close face-to-face daily contact—when they begin to mature. As a result, we do not know what the linguistic abilities of an adult chimpanzee might be. Lucy, like some aging child actor, was forced into retirement just a little after puberty. The laboratory in which she had demonstrated her accomplishments in sign language was closed.

Jane Goodall, who had by then spent a decade and a half living with chimps in the wild, was astonished on meeting Lucy:

In the second half of her life, Lucy lived with other chimpanzees on a small island in Gambia. Her adjustment to Africa was slow and difficult, and she became

But after a year or two in Gambia, thanks to the loving care of Janis Carter, she began to adjust. She had regular contact with humans and was often the first chimp to greet visitors to the island. She was used
to humans. Her relations with other chimps were more strained. She had missed out on the rollicking childhood of a chimp in the wild.

In 1987 Lucy’s skeleton was discovered. The most likely reconstruction of events is that humans came to the island, killed Lucy, probably by shooting her, and skinned her body. Her hands and feet, the very organs that had made her famous, were missing.
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Those responsible have never been found.
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