NO: Linguist Joel Wallman counters that attempts to teach chimps and other apes sign language or other symbolic systems have dem- onstrated that apes are very intelligent animals. But up to now these attempts have not shown that apes have any innate capacity ISSUE 8 for language. Can Apes Learn Language? For YES: E. S. Savage-Rumbaugh, from “Language Training of Apes," in Steve Jones, Robert Martin, and David Pilbeam, eds., The Cambridge Encyclopedia of Human Evolution (Cambridge University Press, 1999) NO: Joel Wallman, from Aping Language (Cambridge University Press, 1992) Learning Outcomes After reading this issue, you should be able to: • Understand several attempts to teach chimpanzees and other apes American Sign Language and some of the difficulties these researchers encountered. • Discuss how ape-language projects in the laboratory are quite different from any study of ape communication in natural settings. Explain some of the criticisms other researchers have offered against these efforts to teach chimpanzees to use sign lan- guage as a symbolic system. • Discuss why chimpanzees learning a small number of signs from American Sign Language might not suggest any inherent ability to use human language. • Evaluate the arguments offered by those researchers who have trained apes to use signs and their relationship to the use of humankind's ability to make tools and use language were two characteris- or more than a century, anthropologists have generally assumed that tics that distinguished humans from all other animals. British anthropologist Kenneth P. Oakley, for example, first published his little volume entitled Man the Tool-Maker (London: Trustees of the British Museum) in 1949, which was republished in new or revised editions in the 1950s and 1960s by the Univer- sity of Chicago Press for use as a supplementary college textbook. In the 1960s and 1970s, Jane Goodall and other primatologists convincingly demonstrated that chimpanzees, our nearest biological relatives, made simple tools, narrow- ing the gap between apes and humans. Beginning in the 1940s a series of other scientists have worked with gorillas, chimps, and most recently the bonobo (or pygmy chimp) attempting to teach these apes simple forms of human-like language. In the 1950s, the psychologist B.F. Skinner had argued that human children learned natural language through conditioning, such that posi- tive responses to utterances from proud parents and other adults essentially trained children to recognize both grammatical patterns and vocabulary. But in the 1960s, linguist Naom Chomsky disproved Skinner's theory showing that human language is so highly complex that it must require some innate biological capability that he called a “language acquisition device." In several respects, all of the ape-language experiments since then have sought to under- stand when this biological capacity for language learning evolved in primates. If apes could use simple language then this biological capacity was present very early in our prehuman lineage. The early years of the ape-language projects encountered one major dif- ficulty . Try as they might , trainers could not get apes to vocalize human words reliably. This difficulty was a consequence of the fact that a chimp's vocal apparatus simply does not allow the possibility of human utterances. So efforts to teach apes how to use language had to overcome the problem of vocaliza- tion with some other means of communication. Since Chomsky's studies of human language, linguists have generally accepted that the manipulation of symbols in systematic grammatical ways, rather than the ability to make utterances, is the most important and complex able linguistic utterances have no difficulty learning the grammar (phonology, aspect of human language. Deaf people who have difficulty making recogniz- morphology, and syntax) of normal language. Thus, if apes could manipulate symbols in linguistic ways, researchers hoped they could demonstrate that the ability to acquire language was a biological capacity shared by at least certain species of the apes and humans. 171 human language. ISSUE SUMMARY YES: Psychologist and primate specialist E. S. Savage-Rumbaugh argues that, since the 1960s , there have been attempts to teach chimpanzees and other apes symbol systems similar to human language. These studies have shown that although apes are not capable of learning human language, they demonstrate a genuine ability to create new symbolic patterns that are similar to very ru- dimentary symbolic activity. 170 E. S. Savage-Rumbaugh YES. UARY Language Training of Apes ? Can apes young human children. great religious grounds-would either like to see humans as just another of the In the 1960s, researchers began using other media that would allow apes to use and manipulate symbols without vocalization. These approaches included plastic shapes on a board, symbols on a computer console, and Amer- have claimed that their chimp or gorilla students have learned symbols for ican Sign Language, long used by deaf people. For more than 30 years, trainers hundreds of words or concepts and many of these researchers have claimed that such ability to manipulate symbols is analogous to symbol use among human beings from our non-human primate relatives has fallen away. This If true, the ability to learn and use language, the last barrier that separates view has its supporters and detractors, many of whom-largely on political or apes or would prefer to view human beings as unique in the animal kingdom. But at issue is whether the long series of ape-language projects has demon- strated that apes can learn to manipulate signs and symbols. Psychologist and primate specialist Sue Savage-Rumbaugh and her hus- band Duane Rumbaugh have been among the most innovative researchers in this field at the intersection of anthropology, linguistics , and cognitive psychology. They have argued that a certain species of pygmy chimps, the bonobo, are biologically closest to Homo sapiens of all the great apes. Their recent work with a bonobo named Kanzi has been among the most successful of these ape-language projects. Here, after tracing the history of these projects, Savage-Rumbaugh concludes that Kanzi's ability to use symbols closely resem- bles similar abilities observed among small human children. Thus, she con- cludes that the ability to use symbols is a trait shared by apes and humans, even though this trait is most well developed among humans. Linguist Joel Wallman interprets the evidence very differently from Savage-Rumbaugh. He acknowledges that the various gorillas, chimps, and bonobos are clever animals that have learned to respond to their trainers in important ways. But he argues that these animals have not learned anything resembling human language. Chimps and bonobos may be clever but they do not have full linguistic abilities, their abilities to use mental abstractions suggests only that very modest versions of these mental processes arose before our branch of the hominin lineage split off from the lineages of the great apes, These selections raise a number of questions about the similarities and differences between apes and humans. What kind of linguistic ability do these ape learners exhibit? Do these symbolic strings genuinely parallel early child- hood language acquisition? Most importantly , do these ape-language studies show that apes and human beings genuinely share a common ability for lan- guage? What are the minimal features that make up any natural language? attempting to answer this question since the late 1960s when it was first reported that a young chimpanzee named Washoe in Reno, Nevada had been taught to produce hand signs similar to those used by deaf humans. Washoe was reared much like a human child. People made signs to her throughout the day and she was given freedom to move about the caravan where she lived. She could even go outdoors to play. She was taught how to make different signs by teachers who moved her hands through the motions of each sign while showing her the object she was learning to 'name'. If she began to make a portion of the hand movement on her own she was quickly rewarded, either with food or with something appropriate to the sign. For example, if she was being taught the sign for ‘tickle' her reward was a tickling game. This training method was termed ‘moulding' because it involved the physical placement of Washoe's hands. Little by little, Washoe became able to produce more and more signs on her own. As she grew older, she occasionally even learned to make new signs without moulding. Once Washoe had learned several signs she quickly began to link them together to produce strings of signs such as 'you me out'. Such sequences appeared to her teachers to be simple sentences. Many biologists were sceptical of the claims made for Washoe. While they agreed that Washoe was able to produce different gestures, they doubted that such signs really served as names. Perhaps, to Washoe, the gestures were just tricks to be used to get the experimenter to give her things she wanted; even though Washoe knew how and when to make signs, she really did not know what words meant in the sense that people do. The disagreement was more than a scholarly debate among scientists. Decades of previous work had demonstrated that many animals could learn to do complex things to obtain food, without understanding what they were doing. For example, pigeons had been taught to bat a ball back and forth in what looked like a game of ping pong. They were also taught to peck keys with such words as 'Please', 'Thank you', 'Red' and 'Green' printed on them. They did this in a way that made it appear that they were communicating, but they were not; they had simply learned to peck each key when a special signal was given. Pilbeam, eds. (Cambridge University Press, 1992, 1999), pp. 138-141. Copyright © 1999 by From The Cambridge Encyclopedia of Human Evolution, Steve Jones, Robert Martin, and David Cambridge University Press. Reprinted by permission. 173 172 YES / E. S. Savage-Rumbaugh 175 174 ISSUE 8 / Can Apes Learn Language? FEBRUARY than what to say when: they learn what words stand for. This type of learning is called conditioned discrimination learning, a term that simply means that an animal can learn to make one set of responses in some aspects of human language can be explained in this way, such as 'Hello', one group of circumstances and another in different circumstances. Although 'Goodbye', 'Please' and 'Thank you', most cannot. Human beings learn more If Washoe had simply signed 'drink' when someone held up a bottle of different from other animals. If, however, Washoe used the sign 'drink' to rep- soda, there would be little reason to conclude that she was doing anything resent any liquid beverage, then she was doing something very different- It was difficult to determine which of these possibilities charcterised her behaviour, as the question of how to distinguish between the 'conditioned response' and a ‘word' had not arisen. Before Washoe, the only organisms that used words were human beings, and to determine if a person knew what a word stood for was easy: one simply asked. This was impossible with Washoe. because her use of symbols was not advanced enough to allow her to compre- hend complex questions. One- and two-year-old children are also unable to answer questions such as these. However, because children are able to answer such questions later on, the issue of determining how and when a child knows that words have meanings had not until then been seen as critical. something that everyone had previously thought only humans could do. Teaching Syntax Several scientists attempted to solve this problem by focusing on sentences instead of words. Linguists argue that the essence of human language lies not in learning to use individual words, but rather in an ability to form a large number of word combinations that follow the same set of specific rules. These rules are seen as a genetic endowment unique to humans. If it could be shown that apes learn syntactical rules, then it must be true that they were using sym- bols to represent things, not just perform tricks. Three psychologists in the 1970s each used a different method in an attempt to teach apes syntax. One group followed the method used with Washoe and began teaching another chimpanzee, Nim, sign language. Another opted for the use of plastic symbols with the chimpanzee Sarah. Still another used geometric symbols, linked to a computer keyboard, with a chim- panzee named Lana. Both Lana and Sarah were taught a simple syntax, which required them to fill in one blank at a time in a string of words. The number of blanks was slowly increased until the chimpanzee was forming a complete 'sentence' . Nim was asked to produce syntactically correct strings by making signs along with his teacher. Without help from his teachers, Nim was unable to form sentences that displayed the kind of syntactical rules used by humans. Nim's sign usage best be interpreted as a series of 'conditioned discriminations' similar to, albeit more complex than, behaviours seen in many less-intelligent animals. This work suggested that Nim, like circus animals but unlike human children, was However, the other attempts to teach sentences to apes arrived at a dif- Sarah and Lana learned to fill in the blanks in sentences in ways that suggested ferent conclusion, perhaps because a different training method was used. Both they had learned the rules that govern simple sentence construction. Moreo- ver, 6 per cent of Lana's sentences were ‘novel' in that they differed from the ones that she had been taught. Many of these sentences, such as 'Please you move coke in cup into room', followed syntactical rules and were appropriate and meaningful communications. Other sentences followed the syntactical rules that Lana had learned, but did not make sense; for example, 'Question you give beancake shut-open'. Thus, apes appeared to be able to learn rules for sentence construction, but they did not generalise these rules in a way that suggested full comprehension of the words. By 1980, Washoe had matured and given birth. At this time there was great interest in whether or not she would teach her offspring to sign. Unfor- tunately, her infant died. However, another infant was obtained and given to Washoe. This infant, Loulis, began to imitate many of the hand gestures that Washoe used, though the imitations were often quite imprecise. Washoe made few explicit attempts to mould Loulis's hands. Although Loulis began to make signs, it was not easy to determine why he was making them or what, if anything, he meant. Loulis has not yet received any tests like those that were given to Washoe to determine if he can make the correct sign when shown an object . It is clear that he learned to imitate Washoe, but it is not clear that he learned what the signs meant. The question of whether or not apes understand words caused many developmental psychologists to study earlier and earlier aspects of language acquisition in children. Their work gave, for the first time, a detailed insight into how children use words during the 'one-word' stage of language learning and showed that children usually learn to understand words before they begin to use them. At the same time, there was a new approach to the investigation of ape language. Instead of teaching names by pairing an object with its sign or symbol and rewarding correct responses, there was a new emphasis on the communicative aspect of symbols. For example, to teach a symbol such as "key", a desirable item was locked in a box that was given to the chimpanzee. When the chimpanzee failed to open it, he was shown how to ask for and how to use a key. On other occasions, the chimpanzee was asked to retrieve a key for the teacher, so that she might open the box. This new approach was first used with two chimpanzees named Sherman and Austin. It resulted in a clearer symbolic use of words than that found in animals trained by other methods. In addition, because these chimpanzees were taught comprehension skills, they were able to communicate with one another and not just with the experimenters. Sherman and Austin could use their symbols to tell each other things that could not be conveyed by sim- ple glances or by pointing. For example, they could describe foods they had seen in another room, or the types of tools they needed to solve a problem. was no evidence that they were intentionally signing to each other or that Although other apes had been reported to sign in each other's presence, there they responded to each other's signs. could using words only to obtain rewards. 176 ISSUE 8 / Can Apes Learn Language? you Sun a teacher, or limited to simple requests. 10 vocabulary FEBRUARY Most important, Sherman and Austin began to show an aspect of sym- bol usage that they had not been taught; they used symbols to say what they were going to do before they did it. Symbol use by other apes had not included descriptions of intended actions; rather, communications had been begun by Sherman and Austin also began to use symbols to share information about objects that were not present and they passed a particularly demand- could be answered only if they knew what each symbol represented. For exam- ing test, which required them to look at symbols and answer questions that ple, they could look at printed lexigram symbols such as 'key', 'lever', 'stick', 'wrench', 'apple', 'banana', 'pineapple' and 'juice', and state whether each lexi- gram belonged to the class of 'food' words or 'tool' words. They could do this without ever being told whether these lexigram symbols should be classified as foods or tools. These findings were important, because they revealed that by using symbols an ape can describe what it is about to do. How Similar Is Ape Language to Human Language? Even though it was generally agreed that apes could do something far more complex than most other animals, there still remained much disagreement as to whether ape's symbols were identical to human symbols. This uncertainty arose for two reasons: apes did not acquire words in the same manner as children-that is, by observing others use them; and apes did not appear to use true syntactical rules to construct multiple-word utterances. The first of these differences between ape and child has recently been challenged by a young pygmy chimpanzee or bonobo named Kanzi. Most pre- vious studies had focused on common chimpanzees because pygmy chimpan- zees are very rare (they are in great danger of having their habitat destroyed in the coming decade and have no protected parks In contrast to other apes, Kanzi learned symbols simply by observing human beings point to them while speaking to him. He did not need to have his arms placed in position, or to be rewarded for using a correct symbol. More important, he did not need to be taught to comprehend symbols or taught that symbols could be used for absent objects as well as those present. Kanzi spontaneously used symbols to announce his actions or intentions and, if his meaning was ambiguous, he often invented gestures to clarify it, as young children do. YES / E. S. Savage-Rumbaugh 177 Unlike previous apes reared as human children, Kanzi was reared in a semi-natural woodland. Although he could not produce speech, he under- stood much of what was said to him. He could appropriately carry out novel 1 show your new toy to Kelly?' and 'Would you give Panzee some of your melon?'. There appeared to be no limit to the number of sentences that Kanzi could understand as long as the words in the sentences were in his During the first 3 or 4 years of his life, Kanzi's comprehension of spoken sentences was limited to things that he heard often. However, when he was For example, the first time he heard someone talk about throwing a ball in the 5 years old, he began to respond to novel sentences upon first hearing them. river, he suddenly turned and threw his ball right in the water, even though he had never done this before. Similarly, when someone suggested, for fun, that he might then try to throw a potato at a turtle that was nearby, he found a potato and tossed it at the turtle. To be certain that Kanzi was not being somehow 'cued' inadvertently by people, he was tested with headphones. In this test he had to listen to a word and point to a picture of the word that he heard. Kanzi did this easily, the first time he took the test. About this time, Kanzi also began to combine symbols. Unlike other apes, he did not combine symbols ungrammatically to get the experimenter to give something that was purposefully being held back. Kanzi's combina- tions had a primitive English word order and conveyed novel information. For example, he formed utterances such as “Ball go group room' to say that he wanted to play with a specific ball—the one he had seen in the group room on the previous day. Because the experimenter was not attempting to get Kanzi to say this, and was indeed far from the group room, such sentence conveyed something that only Kanzi—not the experimenter-knew before Kanzi spoke. Thus Kanzi's combinations differed from those of other apes in that they often referred to things or events that were absent and were known only to Kanzi, they contained a primitive grammar and were not imitations of the experimenter. Nor did the experimenter ask rhetorical questions such as 'What is this? to elicit them, Kanzi's combinations include sentences such as 'Tickle bite' , 'Keep-way balloon' and 'Coke chase'. As almost nothing is yet known of how pygmy chimpanzees communicate, they could use a form of simple language in the wild. Kanzi understands spoken English words, so the ability that is reflected in language comprehension is probably an older evolutionary adaptation than is the ability to talk. that only humans can talk and think. Certainly, there is now no doubt that Studying ape language presents a serious challenge to the long-held view apes communicate in much more complex and abstract ways than dogs, cats and other familiar animals. Similarly, apes that have learned some language skills are also able to do some remarkable non-linguistic tasks. For example, they can recognise themselves on television and even determine whether an Image is taped or live. They can also play video games, using a joystick to catch Kanzi learned words by listening to speech. He first comprehended cer- tain spoken words, then learned to read the lexigram symbols . This was possi- ble because his caretakers pointed to these symbols as they spoke. For example, ran across wild strawberries growing in the woods. He soon became able to lead people to strawberries whenever they asked him to do so. He similarly learned the spoken names of many other foods that grew outdoors, such as wild grapes, honeysuckle, privet berries, blackberries and mushrooms, and could take people to any of these foods upon spoken request. and trap a video villain. 178 ISSUE 8 / Can Apes Learn Language? NO Joel Wallman talents for language and communication of our closest relatives. Sharing Scientists have only just begun to discover ways of tapping the hidden 98 per cent of their DNA with human beings, it has long been wondered why African apes seem so much like us at a biological level, but so different when it comes to behaviour. Ape-language studies continue to reveal that apes are Aping Language Sat Sun more like us than we ever imagined. 9/10 Experiment FEBRUARY philosophers. periments carried out over the past two decades ... attempted to impart a language, either natural or invented, to an ape. The debate engendered by these projects has been of interest-consuming for some, passing for others- nature, among them anthropologists, psychologists, linguists, biologists, and to all of those whose concerns include the enduring questions of human An adequate treatment of the linguistic capabilities of apes entails consi- deration of a number of related issues, each of which is an interesting problem ile its own right. Continuities in primate mentality, the relationship between language and thought in the individual and in the species, and the origin of language ... are themes that ... recur throughout this [debate). [None of the ape-language projects succeeded, despite employing years of tutelage far more intense than that experienced by most children, in implanting in an ape a capacity for language equal to that of a young child, let alone an adult. ... Why the Ape-Language Controversy Is a Controversy All scientific arguments have in common at least these elements: (1) a mini- mum of two positions regarding the subject in dispute, positions generally held to be irreconcilable, and (2) an intensification of the normal emotional investment of the scientist in his or her position, due in some measure to the contending itself but perhaps also related to the ideological significance of the subject within the larger society. If, in addition, the argument includes sugges- tions of fraudulent or quasi-fraudulent procedures, the disagreement becomes a controversy. To the extent that this is an accurate characterization of scien- tific controversies, the ape-language debate is an exemplary one. The radical opposition of opinion about the achievement of the various ape-language projects is well conveyed by the following quotations: (Washoe) learned a natural human language and her early utterances were highly similar to, perhaps indistinguishable from the early utter- ances of human children. (Gardner and Gardner 1978, p. 73) From Aping Language by Joel Wallman (Cambridge University Press, 1992). Copyright © 1992 by Cambridge University Press. Reprinted by permission. 179
Purchase answer to see full attachment