When Garner boldly proposed to take a phonograph to Central Africa, sit in an electrified cage, and study simian tongues in the wild, there was hope the language evolution debate could be settled once and for all. Alas, the expedition did not turn out as planned. Garner’s quest to find convincing evidence in the African jungle was a failure even before it had begun. In spite of links with Edison, he did not manage to obtain a phonograph for the mission. When he returned, he faced an avalanche of accusations in the popular press about inconsistencies in his reports about what had occurred on the expedition. Rumors spread that he did not spend months in the deepest jungle but instead lived in or near the comforts of a mission; the stories led to widespread suspicion and ridicule. In any case, Garner did not return with new evidence but with a chimpanzee that could not speak or be deciphered—and that quickly perished. There was no support for his claims about chimpanzee and gorilla language. Instead of making a mark in the annals of evolutionary theory, Garner’s dream to learn the languages of animals became firmly entrenched in the realm of fiction, most notably in the character of Hugh Lofting’s Dr. Dolittle. Serious scientific attempts to discover simian languages, or to teach them ours, were put on hold.
In a fascinating account of Garner’s story, the science historian Gregory Radick suggests that one reason for this change in zeitgeist might have been the rise of ideas about evolution proceeding in leaps, as Stephen Jay Gould maintained, rather than in small, gradual steps. This reduces the need to find precursors of human language in apes. As I clarified earlier, Darwin’s theory does not have a real problem with the existence of radical discontinuities in the current record. Creatures that may have had precursors of human language, such as Homo erectus, are now extinct (leaving an apparent discontinuity between extant species). Furthermore, precursors of language need not even have been in the domain of vocalizations. It is possible that language first evolved in gestural form. Indeed, this idea of a gestural origin of human language, moving subsequently from hand to mouth as it were, is increasingly gathering momentum. The search for language precursors in primate vocalization may hence be a case of barking up the wrong tree.
Garner’s abandoned playback approach had its revival in the 1980s, when ethologists Dorothy Cheney and Robert Seyfarth conducted seminal studies on vervet monkey alarm calls at the foot of Mount Kilimanjaro. By recording alarm calls and then playing them back to the unsuspecting group at a later stage, these researchers established, for the first time, that nonhuman animal vocalizations may have meanings not entirely unlike human words, even if there exist far fewer of them. The animals make different alarm calls when they see a snake, an eagle, a leopard, or a human. When played back the monkeys tend to react differentially and appropriately to such calls. That is, they hide under a tree if the call is the eagle alarm, but they run up the tree if it is the leopard alarm.
These calls are gradually learned but limited to alarms only. There is no evidence for vervets stringing them together, let alone generating open-ended sentences. They do not show any evidence for recursion in their communication. A monkey may on occasion falsely utter the alarm call for “leopard,” making the rest of the troop run up the tree while he stays behind and eats the food the others discarded. This seems like a pretty clever form of tactical deception, but it also illustrates the lack of reasoning about what the others know. The monkeys up in the tree do not seem troubled by the fact the individual that cried wolf did not flee himself and instead took their food. They do not seem to reflect on (that is, meta-represent) the discrepancy between what the individual’s alarm represents and what his lack of running away represents. There is no evidence of reflective embedding in other monkey communication either. Although perhaps a building block on which human language was constructed, the calls of monkeys are limited in terms of flexibility, meaning, and use.
Indeed most animal vocalizations seem to be under emotional rather than cognitive control. When researchers stimulate a subcortical part of the brain known as the periaqueductal gray, it causes meowing and growling in cats, shrieking and barking in rhesus monkeys, echolocating in bats, and laughing in chimpanzees and humans. Destruction of this area causes muteness. The area is indispensable for animal vocalization and nonverbal human vocalization. As we have seen, human speech, on the other hand, is primarily driven by cortical areas of the left hemisphere that allow for voluntary control and extreme flexibility. Animal vocalization may hence not be closely related to human speech.12
Nonetheless, some animal communication systems are quite sophisticated. Bee dance, for instance, communicates the size of a food source, the distance, and the horizontal direction. However, close examinations of communication systems of animals have found them to be restricted to a few types of information exchanges, typically to do with reproduction, territory, food, and alarm. There appears to be little content transferred beyond these realms. There is as yet no sign that animal communication features the open-ended flexibility that typifies human language.
What about whales? you might ask. Humpback whales sing in the most curious manner, they have large brains, and there is even evidence that they learn the songs from each other. Are they talking about us behind our backs? Disappointingly, the answer is “probably not.” The possible information content of a humpback whale song is estimated to be low indeed—just enough to say, “Hello, baby. Check me out.” Researchers now think it likely the songs are serving a simple mate-attraction function.
Thus far, all attempts at deciphering animal communication systems point to narrow repertoires, devoid of the recursive characteristics that make human language so flexible. Yet our knowledge of animal communication systems is still quite limited. Perhaps there is sophisticated communication going on that we have not figured out. For instance, only recently has work on the alarm calls of prairie dogs suggested that they may signify more details than do vervet monkeys. Cephalopods, such as squids, octopus, and cuttlefish, change their color and patterns not only for camouflage but perhaps also to communicate surreptitiously. There is evidence to suggest that they use reflections of polarized light from their skin to signal others without predators being able to perceive it. Given that more might be going on in animal communication than meets the eye, it is prudent to remain cautious. Recall that absence of evidence is not equivalent to evidence of absence.
Another approach is to tackle the problem from the other end. Can we teach human language to animals? Linguists are increasingly questioning whether humans are innately wired for a universal grammar; they highlight cultural learning instead. Perhaps, then, animals can acquire human language in the right cultural circumstances. From fairytales to serious literature, our folklore is replete with stories in which such attempts succeeded. Is there any truth to these imaginings?
I cried out a short and good “Hello!” breaking out into human sounds. And with this cry I sprang into the community of human beings, and I felt its echo—“Just listen. He’s talking!”—like a kiss on my entire sweat-soaked body.
—FRANZ KAFKA
IN FRANZ KAFKA’S FAMOUS SHORT story “A Report to an Academy,” a chimpanzee explains in eloquent prose how he learned the human ways in captivity. In the real world nothing like this has ever happened. In spite of attempts by Garner and others, no ape has learned to speak. Great apes do not seem to have the voluntary fine-motor control of the face and voice that we use in speech. Their vocal apparatus does not enable articulation of the required vowels.
Parrots, however, can mimic human words. Indeed, the perhaps most famous speaking parrot, the African grey parrot Alex, was said to have been able to produce some 150 English words. His trainer, the comparative psychologist Irene Pepperberg, worked with him for thirty years and reported that Alex could name some fifty objects, count to six, and form contrasting concepts such as over/under, bigger/smaller, and same/different. Although there was no evidence of recursive grammar, some of his communications included turn taking and appropriate use of phrases suc
h as “I am sorry.”
Other species have been examined with mixed success. The comparative psychologist Louis Herman trained bottle-nosed dolphins to follow complex gestural commands. The dolphins evidently understood a range of instructions and even responded appropriately to changes in symbol order. Seals have also been trained similarly. A border collie, Rico, was shown to understand verbal instructions of its owner beyond what was previously imagined. From ten months onwards, the owner regularly placed three items around the house and asked for Rico to fetch them. At age ten Rico was able to discriminate about two hundred object words. Rico would even learn new names for objects on the basis of exclusion. That is, when asked to fetch something with a new name, the dog would select the only object which name it did not know. This ability is called fast mapping and is sometimes supposed to be a key to children’s rapid word acquisition. Impressive as these cases are, none of these efforts include any symbol production on the animals’ part. There is hence as yet no conversation with these animals. Great apes, on the other hand, have demonstrated capacities in both comprehension and production.
Although vocal language is impossible for great apes, researchers have had some success in teaching them sign languages. Great apes have been taught to produce and understand several hundred signs. Famous examples include the chimpanzee Washoe, the gorilla Koko, and the orangutan Chantek. An alternative approach is to teach the apes arbitrary visual symbols mounted on a board that can be touched to communicate. Again, up to a few hundred such symbols have been learned, for example, by the chimpanzee Sarah and the bonobo Kanzi.
The initial enthusiasm that great apes could learn language was challenged by the psychologist Herbert Terrace. His work with a chimpanzee named Nim Chimpsky—a pun on Noam Chomsky—suggested that the apes simply and slowly learn to use the symbols through associative learning rather than through a real understanding of the representational function of words.13 He concluded that Nim had nothing like human language and cast doubt on previous studies. A heated dispute ensued between rich and lean interpretations of the ape language projects.
One new line of evidence on this debate comes from research on great apes’ understanding of pictures and models. Even if they cannot draw symbolically themselves, one can examine whether they have a capacity for representational insight. As we have seen above, in developmental research this faculty has been investigated by asking a child to find an object in a room after being shown the hiding place in a picture of that room. There is now evidence that chimpanzees can pass such tasks. The psychologists Valerie Kuhlmeier and Sally Boysen showed that their chimpanzees were able to find a hidden object in a room after being shown on a photograph or scale model of the room where the object was going to be hidden. The apes appear to be able to interpret these images and models as a source of information about the real thing.
Such results may offer some consolation to the advocates of rich interpretations of the “ape language” projects, as these studies are sometimes known. It is generally accepted now that great apes have demonstrated some significant understanding of the symbols they use but also have limits.14 They can pick up symbols without explicit training, name objects appropriately, and comprehend novel requests. Alas, the apes themselves have contributed somewhat less to the debate than one might have hoped. They have not told us much about their worldview. Their talk is nothing like the reflections Kafka imagined. Rather, the apes tend to use a single word, or a string of two or more words, to deal with their present situation: “give apple,” “tickle chase,” and the like.
Ape signs are primarily requests, and Terrace has argued that apes only utter imperatives and no declaratives. However, a recent analysis of decades of data (some hundred thousand utterances) of three language-trained apes found that 5.4 percent of signs may be classified as comments or statements (i.e., declaratives). The same analysis found a mere eleven incidences in which the apes named something to show, offer, or give it, and none in which they simply tried to get attention. Though the apes make some reference to actions that have just happened or are about to happen, they have not acquired tense or symbols to refer to temporal displacement—we cannot enjoy a mutual trip down memory lane or debate the remote future with them. However much we may want them to, they do not ask us the big questions about where they come from, what they are, and where they are going.
This is not for want of trying. At least a few accounts of curious and elaborate responses to philosophical questions have been reported. The gorilla Koko, for example, is said to have responded as follows to five instances of being asked, “Who are you?”
1.Me gorilla nipples tickle.
2.Polite-Koko Koko nut nut polite.
3.Koko polite me thirsty.
4.Polite me thirsty feel Koko love.
5.Koko polite sorry good frown.
These responses all share at least one reference to the animal’s proper name, Koko, or even to “me” and “gorilla.” This is interesting, given great apes’ capacity to recognize themselves in mirrors. Yet this example also illustrates the utter lack of syntax that is emphasized by scholars to support a lean interpretation. There is no structure or embedding of phrases in their production—no evidence for the open-ended generativity that is so typical of human language. In spite of the trainers using syntax, none of the animals seems to have picked this up.15 So perhaps Chomsky and colleagues are right in arguing that recursive syntax is distinctly and uniquely human.
There have been challenges to this conclusion. The bonobo Kanzi can generate two- and three-word combinations that appear to follow simple rules, such as putting the verb before the noun. However, his most frequent three-word sentences are all similar requests (the top five are: chase person person, person pat person, person person pat, person chase person, person grab person). He apparently can understand quite complex verbal English commands. For instance, he will perform unusual requests such as “put the keys in the refrigerator.” His comprehension is better than his production and has been likened by comparative psychologist and trainer Sue Savage-Rumbaugh to the level of competence of a two-and-a-half-year-old child—an impressive performance. Kanzi is probably the linguistically most competent nonhuman alive.
Yet linguists continue to argue that not even these apes have the hallmarks of language. Steven Pinker, for example, insists that they “just don’t get it.” None of them, not even Kanzi, shows convincing evidence of recursion and the generativity that it provides. There is no use of grammatically important characteristics like inflections and tense, for example, and there is no distinction between statements and questions. Grammar aside, they show no sense of the real logic of having a symbolic communication system. They do not regularly teach each other, point out things for others’ benefit, or ask for the names of things. If they had understood the principle, one would expect them to want to learn more useful words. This limit to their competence is also evident in the otherwise impressive attempts at teaching apes to count. Sally Boysen, for example, taught her chimpanzees to count using Arabic numerals up to nine. Each number took equally long to acquire. What’s more, they did not get the recursive rule that allows us to use these numbers and reassemble them to represent virtually any quantity. There also appear to be limits to the pragmatic side of their communication, as I will discuss in the next chapters. We still wait for an animal to tell us about what it is like to be what they are; to tell us their views on life, politics, philosophy; or to even tell a simple story (let alone to report to an academy).
In sum, there are indeed some characteristics of language that appear to be uniquely human. On current evidence, it is fair to say neither in their natural communications, nor in our attempts at teaching them human linguistic systems, have animals provided evidence for a full-fledged language. Animals do have communication systems, and they do form concepts. They can learn humans’ arbitrary symbols, and some appreciate the fundamental attribute that a symbol can inform about another object or event. Some spe
cies, like parrots, can produce speech sounds, though many lack adequate multitasking capacities and voluntary control of face and vocal tract to establish vocal conversations. However, sensory-motor skills may not constitute an absolute barrier, given that a language faculty could be expressed in other ways.
What appears to be lacking, even in great apes, is a motivation to find means to exchange what is on each other’s minds. Animals have not demonstrated the capacities required to invent and agree on arbitrary symbols for concepts or on grammar rules that allow for efficient combination of such symbols. They have not developed an open-ended, generative communication system comparable to a human language, nor have they been able to learn one of ours. It looks increasingly likely that humans do not have an innate universal grammar that enables language; instead, we culturally inherit a specific language from people who, based on more general capacities for embedded thinking, manage to establish such symbols and rules for the practical purpose of exchanging the matters on their minds—minds filled with thoughts about past and future, about others’ minds, about problems and opportunities, about cooperation and morality. Without such complex mental content there would be little use for an open-ended communication system like ours. To these mental contents, therefore, we turn next.
1Huxley goes on: “and thanks to words, we have often sunk to the level of the demons.”
2This is the case for virtually all right-handers and two-thirds of left-handers. In particular, Paul Broca discovered that people who had lost the capacity to produce speech had damage to the left frontal lobe, now known as Broca’s area, and Carl Wernicke found that people who had difficulties understanding language had damage slightly further back on the left, in what came to be known as Wernicke’s area.
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