Talking with Chimps

There has always been much fascination with primates and especially with chimpanzees because they are so similar to ourselves. Many researchers feel that chimps may be so much like humans that they may be able to understand and communicate with us using a language that we could understand. Since we are well aware that a chimp's anatomy renders it virtually impossible to speak a human language, many researchers began to wonder whether it was possible for a chimp to communicate with us in other ways . This idea resulted in using methods from American Sign Language to lexigrams in an attempt to communicate. The question is was one method more effective than another in facilitating communication, and perhaps more importantly, is it possible for a chimpanzee to understand and reproduce, in a none verbal manner, a human language?

In order to establish whether chimpanzees are capable of understanding human language we first must define what human language is. The noted linguist Noam Chomsky offers perhaps the best comprehensive definition of human language. First, he says that human language has structural principles such as grammar or a system of rules and principles that specifies the properties of its expression. Second, human language has various physical mechanisms of which little is known but it does seem clear that "laterization plays a crucial role and that there are special language centers, perhaps linked to the auditory and vocal systems"(Chomsky, 1980). The third quality of human language is its manner of use. Human language is used for expression of thought, for establishing social relationships, for communication of information and for clarifying ideas. Another characteristic of human language is that it has phylogenetic development in the sense that language evolved after humans had separated from the other primates. Therefore language must have had a selective advantage and must coincide with the proliferation of the human species. Finally, human language has been integrated into a system of a cognitive structure(Chomsky,1980).

Having defined what human language is or more precisely what it consists of, it is important to now turn to a few of the many chimp language experiments to see if any of these primates seemed to have understood language in the manner that Chomsky defined it. The first Chimp language experiment ever conducted took place in the 1930's by W.N. and L.A. Kellogg with a 7 1/2 month old chimp named Gua. The Kellogg's compared the chimp's development with that of their newborn son with the intention of determining how much of human language is derived from heredity and how much is derived from education. This experiment only lasted for nine months and at its end it was determined that the chimp could not learn those aspects of language that a human inherently knows (Animal Communications:Primate Studies). This experiment is only worth mentioning because it was the first such experiment of its kind and, due to that fact it had many schematic problems it does not warrant further discussion.

The first chimp experiment that warrants real investigation was done by Allen and Beatrice Gardner in the 1960s and was the first to use American Sign Language in primate communication. The Gardner's decided to use a chimpanzee for their language experiment because they felt that the chimpanzee is highly intelligent, and more importantly,a highly social animal. They felt that sociability was a prime factor in the acquisition of language in human beings. After deciding on using a chimpanzee the Gardners struggled over how to go about teaching it human language. They decided that it would be useless to teach the chimp to speak mainly because its vocal apparatus is so different from humans. In addition, chimps tend to make noise only when excited and the Gardners felt that this tendency would not fit their needs very well. They finally decided on American Sign Language or ASL as the mode of communication because it doesn't involve speech and also because it would be fairly easy for a chimp to manipulate its hands in order to form signs (Gardner and Gardner, 1969).

Washoe

The training of Washoe, the chimp used in the experiment, began when she was 11 months old and lasted 51 months. During this time she acquired 151 signs. It was the Gardners' observation that chimps and humans are very similar in many aspects such as blood chemistry, sensory system, as well as a prolonged dependency of child on mother. It was for these reasons that the Gardners decided that it would be possible to teach a chimp ASL and concluded that a chimp would be very similar to a human child in learning ability. Due to this assumption they treated Washoe as if she was a human child, she had scheduled meals, nap times,bath time etc...(Gardner and Gardner,1980). The idea was to immerse Washoe in the world of the deaf and ASL and to carry on spontaneous conversations between her and her trainers. One of the first things that the Gardners noticed was that a lot of Washoe's signs seemed to be imitation, much like the way an infant would imitate their parent. For instance, every night before she went to bed Washoe would brush her teeth and the sign "toothbrush" would be signed to her. One day Washoe went into the bathroom and signed "toothbrush" by herself with no provocation. The Gardners feel that this was done for the sole reason of communication, much like the way a small child might communicate to their parent (Gardner and Gardner, 1969). Perhaps the most significant finding of the Gardners was that it appeared as though Washoe produced her own combinations of words such as "dirty Roger" where dirty is used as an expletive and "water bird" upon seeing a swan on a lake. The Gardners argue that it was highly unlikely that Washoe would be able to combine the right words, in the right context, unless she understood at least some of the rules of human language (Animal Communications:Primate Studies).

The Gardners are however, quick to point out that many of Washoe's early signs were "acquired by delay imitation of the signing behavior of her human companions but very few if any, of her early signs were introduced by immediate imitation" (Gardner and Gardner,1969). The most effective way they found to teach the chimp to sign was to form her hand in the shape of the sign and use constant repetition. They are also quick to point out that by the time the project was finished Washoe knew more than 30 signs including object names, using pictures of objects as well as the actual objects. She also had the capability to form sentences with the words that she did know, most of them involving the pronouns "I" and "you" (Gardner and Gardner, 1969). It is clear that the Gardners did indeed feel that Washoe could understand some things in ASL even though her vocabulary was quite limited. Unfortunately Washoe was studied for only 51 months so their understanding of her full language development capability was limited by this fact.

Herb Terrace was very interested in project Washoe and studied the only two video tapes available of her using ASL. While viewing the film The First Signs of Washoe , Terrace noted that Washoe's utterances either followed or interrupted Gardener's utterances and that Gardner signed the word "time" just before Washoe signed the phrase "time to eat". In the other film Teaching Sign Language to the Chimpanzee: Washoe the Gardners claim that Washoe came up with the sign "Baby in My Drink" all on her own when she found a doll in her cup. They maintained that this was a creative process and hence was one of the major components of human language. After viewing the tape over and over again Terrace concluded that only the words "my drink" were not prompted by the trainer and therefore it is not a spontaneously generated utterance. Terrace concluded that Washoe, on the whole, was merely mimicking her trainer and therefore really did not comprehend the human language or its grammatical rules (Terrace et all, 1979).

Another method employed in an attempt to teach a chimpanzee human language was employed by Sarah and David Premack in 1966. The chimpanzee that they used was a six year old female named Sarah who was brought to live in a cage at the University of California, Santa Barbara, and was treated strictly as a laboratory animal. Instead of using ASL the Premacks decide to use plastic chips of various shapes and colors, each representing an English word. Sarah was to place these various chips on a "language board" in order to form sentences. She learned to do this by first seeing a piece of fruit, such as an apple, followed by being shown the plastic chip that represented an apple. Sarah was given the apple to eat if she could pick out the symbol for apple and place it on the language board. After she had mastered this task the same method was employed with common objects and people. The second stage consisted of stringing the symbols together to form such sentences such as /Mary/ + /Apple/ on the board to symbolize "Mary to give apple". The next step involved putting three symbols together to form such sentences as /Mary/ + /to give/ + /apple/ while the final step consisted of four unit utterances such as /Sarah/ + /to / /give/ + /apple/ + /Mary/. The Premacks claim that by the time they had finished working with Sarah she knew 130 signs and could make meaningful sentences of up to eight units long. It is important to point out, however, that at no time did Sarah ask any questions though when alone in her cage Sarah would form the utterances that she had just learned onto her board.

Another method was employed by Duane Rumbaugh in the mid 1970's in which he decided to teach a chimpanzee language by employing symbols. The researchers felt that it was important to eliminate human contact in teaching chimps language. They felt that automation would prevent anyone from cuing the animal and the training could be more efficient and would require less people. A computer would perform certain functions such as dispensing food or displaying slides in response to an operator lightening up the proper symbol.The system that they decided to use would provide 24 hour a day operations that would not require a human operator. The chimp that they worked with was a two year old named Lana. In the lab they built her a room made out of plastic and glass which had two way visual access. Lana was given a keyboard which had keys (lexigrams) that each represented a word. Outside of Lana's room there was another keyboard that allowed for two way conversation between the chimp and the researcher. Between the two keyboards was a computer that monitored all linguistic events , and was also used to evaluate Lana's use of language and to record all other communications (Rumbaugh,1980).

Lana was initially taught to use a single key, followed by teaching her how to ask for things such as food and water. Eventually Lana would enter into conversation without being prompted to do so. It was, however, found that "Lana has been prone to converse whenever she must do so in order to receive something exceptional or whenever something not in accordance with the routine delivery of food and drinks has occurred- in short, when some practical problem arises for her"(Rumbaugh,1980). For her language is the means to receive something that she desires, and seems to serve no other useful purpose.

Terrace also studied Sarah's and Lana's progress and came up with some not too surprising conclusions. He felt that due to training Sarah and Lana both learned to produce a specific sequence of words in order to obtain what they wanted, but there is no evidence that suggest that Lana and Sarah understood all of the meanings of all of the words in the sentences that they produced. "Except for the names of the objects they requested, Sarah and Lana were unable to substitute other symbols in each of the remaining positions of the sequences that they had learned"(Terrace, 1979). Terrace felt that the Premacks were teaching problem solving and not language and " Premack's conclusions were not well-founded given his experimental design and results "(Animal Communication:Primate Studies). For example Terrace noted, look at Premack's claim that Sarah learned the word "insert". Premack's only proof of this is one example in which Sarah saw "Sarah banana pail insert" on her language board and proceeded to do as instructed. Later, however, when the word "insert" was tested against the word "give" Sarah could not distinguish the two. Terrace argued that Sarah's following instructions did not involve understanding the messages on the language board, instead it involved doing what she was trained to do in the first part of the test, inserting the banana in the pail (Animal Communication:Primate Studies).

The final project that I wish to look at was started in 1973 by Herb Terrace. Terrace's goal was to amass and analyze a large body of data through detailed analysis of a chimpanzees communicative behavior. He went about this by examining a large body of the ape's utterances for regularities of a language order and would thereby decide whether a chimp could use one or more rules of finite state grammar. The chimp that was used for this experiment was a two week old chimp named Nim Chimpsky (obviously a play on Noam Chomsky) but work with him did not officially begin until he was nine months old. Nim was taught the pidgin sign language that was used by the Gardners as well as the molding and imitation method that they had used on Washoe. During the forty four months that Nim was studied he learned 125 signs, most of which were common and proper nouns , though he also learned many verbs and adjectives, as well as a few pronouns and prepositions(Terrace,1983).

In the months that Nim was observed his teacher's recorded 20,000 of his utterances which consisted of two or more signs. In many cases it was found that Nim used particular signs in either the first or second position, no matter what other signs that sign was combined with. For example "'more' occurred in the first position in 855 of the two sign utterances in which 'more' appeared, and of the 348 two sign combinations containing 'give' 78% had 'give' in the first position"(Terrace,1983).

The next step for Terrace was to determine if there was a semantic relationship between Nim's two sign combinations. In order to determine this 1,262 of Nim's two sign combinations were studied, and it was found that there were 20 categories of semantic relationships which accounted for 85% of the 957 inferable two sign combinations. Terrace became convinced that the analysis performed on Nim's combinations provided the most compelling evidence to date that a chimpanzee could use "grammatical rules, albeit finite state rules for generating two sign sentences"(Terrace,1983). Terrace then proceeded to look at the differences between Nim's and a child's use of language to see if the chimp understood language as a human child does. Initially Terrace believed that Nim was capable of understanding and using sentences but it was not until he reviewed the videotape of Nim did he begin to question his findings.

The first thing that Terrace noted was that there was no increase in the length of Nim's sentences over time , though there was an increase in his vocabulary. It was understood that a child would increase the length of their utterances and their vocabulary over time. The second thing that Terrace noted was that Nim would repeat words or sequences of words constantly, such as "Eat Nim, Eat". This occurs rarely in children. Another noticeable difference was that in a child the longer the sentence, the more complex they become. This, however, was not true in Nim's case, instead it appeared that Nim learned that the more he signed, the better his chances were of getting what he asked for. This was seen before in the chimp Lana. It also appeared that Nim did not add more informative signs to request something , he would just keep repeating the same signs over and over. It was also noted that Nim signs were not spontaneous unlike a child, and in fact only 12% of his utterances were not preceded by a teacher's utterance. Another point of contention was that "as a child gets older the proportion of utterances that are full or partial imitations of the parent's prior utterances decreases from less than 20% at age 21 months to almost 0 by the age of three" (Terrace,1983). In Nim's case at the age of 26 months 38% of his utterances were full or partial imitations of his teachers and by the time he was 44 months it was 54%. So in fact Nim imitated the trainers more as he got older, instead of less as in the case of a human child.

Another point worth mentioning is that a child by the age of 26 months adds at least one word to their parent's prior utterances 22% of the time and by the age of 36 months this is increased to 42%. In Nim's case however it was found that fewer than 10% of his utterances during the 22 months that he was video taped were expansions of the trainer's sentences. The final major difference between Nim and a child is that Nim was as likely to interrupt his trainer as not while children tend to interrupt their parents very rarely. Also, Nim never added new information to the conversation and showed no evidence of turn taking. This eventually led to the conclusion that he did not understand the rules of language because he did not employ them . Terrace thus concluded that Nim was just copying his trainer's signs (Terrace, 1983).

There are a few studies going on today that are concerned with teaching a chimpanzee how to communicate by using a human language. Perhaps one of the most interesting is being preformed by Sue Savage-Rumbaugh. Savage-Rumbaugh feels that it is more important to concentrate on the question of whether apes understand the signs they produce, instead of do they have grammatical capabilities. Therefore her studies move away from the design features of language such as productivity and displacement, which were so popular in the other studies. Savage-Rumbaugh points out that human languages use symbols, which consist of three components. The first of these is the physical external substance such as a word, "mountain" for example, either written down or spoken with a specific linguistic pattern. Second, there is a relationship between this and a real mountain which is known as a referent because the word refers to it. This means that when the word mountain is mentioned the person conjures up a mental representation of a mountain. Finally, symbols in a language allow us to think about things that are not present , and even about things that do not exist (such as dragons and unicorns) (Animal Communication:Primate Studies).

Savage-Rumbaugh suggests that in all previous primate communication experiments the primates were not using their signs symbolically. She feels that the apes had merely "learned to associate certain behaviors (making or seeing a particular sign) with certain consequences (getting something to eat) -similar to a dog, who upon hearing the word 'walk' knows its going to go for a walk" (Animal Commutation:Primate Studies). The previous language communication experiments she feels did not test enough to see if the animal truly had acquired a word. In her experiments Savage-Rumbaugh works with two chimps, Sherman and Austin, in an attempt to teach them language skills with a computer and the lexigrams that Lana used. Linguists have found that the use of symbols in humans is a complex series of independent phenomenon, and the ability to produce a symbol was found to employ three separate abilities. In Sherman and Austin's case the first of these abilities is being able to request an object by using a lexigram and an object. Second is the ability to name an object, which involves associating a lexigram with an object. The third ability is comprehension of the symbol. In the case of the chimpanzees these three abilities had to be taught separately and the presence of one of this abilities did not necessarily indicate the presence of one of the other abilities (Animal Communication:Primate Studies).

Savage-Rumbaugh claims that she has been successful in teaching the chimps these skills and the links between them which occur naturally in human beings. She says that unlike Nim, Sherman and Austin participate in turn taking, they do not imitate their trainers and they produce messages, she claims, because they truly want to make statements and not because they must. Critics argue that these apes have been trained and have no idea of what they are saying or are not using their signs symbolically. Due to past evidence, more data needs to be produced and studied before any conclusions can be drawn.

It is obvious that there is no clear answer to the question that posed at the beginning of this paper, namely can a chimp understand and reproduce a human language. Although the verdict is still out on how much a chimp understands what is being said versus how much it is mimicking its trainer, it does seem very apparent that the chimps do have some skills that we previously did not believe they had. Although they may only use language to get what they want, the point is that they are in fact using a language, even if it is not in the way that a human child might use language. They are not human children so it does not seem logical that they would use language in exactly the same way. Either way it does appear that chimps are capable of understanding human language, to what degree still needs to be determined. It is important to keep in mind as well,that chimps have not had the time that humans have to evolve the complexities of language, but given enough time they might be able to master the abilities of language, and perhaps even surpass us.

LITERATURE CITED

Animal communication: true language? (1991) In Language Files: Materials for an Introduction to Language. Dept of Linguistics/ The Ohio State University, pp.31-33.

Chomsky, Noam (1980) Human language and other semiotic systems. In Thomas A. Sebok and Jean-Umiker-Sebok (eds.): Speaking of Apes: A Critical Anthology of Two-Way Communication with Man. New York: Plenum Press, pp. 429-440.

Gardner R. Allen and Gardner Beatrice (1969) Teaching sign language to a chimpanzee. Science 165:664-672.

Gardner R. Allen and Gardner Beatrice T. (1980) Comparative psychology and language acquisition. In Thomas A. Sebok and Jean-Umiker-Sebok (eds.): Speaking of Apes: A Critical Anthology of Two-Way Communication with Man. New York: Plenum Press, pp.287-329.

Rumbaugh Duane M. (1980) Language behavior of apes. In Thomas A. Sebok and Jean-Umiker-Sebok(eds.): Speaking of Apes: A Critical Anthology of Two- Way Communication with Man. New York: Plenum Press, pp.231-259.

Terrace H.S. (1983) Apes who "talk": language or projection of language by their teachers? In Judith de Luce and Hugh T. Wilder (eds.): Language in Primates: Perspectives and Implications. New York: Springer-Verlag New York Inc. pp. 22-39.

Terrace H.S., Petitto L.A. , Sanders R.J. and Bever T.G. (1979) Can an ape create a sentence? Science 206:891-902.

Return to The Primate's Home Page