Experiment Module: Attempts To Teach
Language to Primates
Chimpanzees in their natural habitat display social communication that is quite elaborate, based on gestures, manipulations of objects, and facial expressions. They also have a natural system of vocalization that seems to include certain referential components, such as cries of alarm to inform the other members of their group of a particular kind of danger.
Despite all this, communication in the great apes is really quite different from human communication, for two main reasons: communication among the great apes is essentially affective (whereas human language is cognitive and referential) and is controlled by subcortical structures (whereas human language is essentially cortical).
Human language still appears to be unique from a semantic standpoint, that is, in its ability to associate particular meanings with arbitrary symbols. But because these human language abilities must have evolved from abilities present in our primate ancestors, many researchers have believed that it might be possible for primates to learn human language.
One outstanding finding from the research to date: despite repeated attempts since the 1940s to rear juvenile chimpanzees like children, they have never managed to speak, because their larynxes do not let them produce the sounds of human language. The chimps do, however, seem able to learn a few rudiments of symbolic communication if they are given the chance to use symbols mounted on pieces of plastic, or some elements of sign language, or a computer screen with a symbol keyboard. With a symbol keyboard and adequate training, some chimpanzees have learned to choose among over 400 symbols to construct expressions and hold rudimentary conversations with their teachers. Researchers have even claimed that their most talented animals managed to master a vocabulary of a few thousand words, the equivalent of the language abilities of a human child 3 to 4 years old.
The bonobo monkey Kanzi regularly used 250 lexigrams (symbols, each representing a single word) from a selection of 500. Dolphins also can communicate concepts to one another. If a group of dolphins learns a task, and then a new dolphin is placed in their tank, they can explain the task to him or her. They can also distinguish between reality and representations of reality (such as on a television screen).
Two of the most famous primates to have learned the meanings of sign-language gestures were Washoe—a chimpanzee reared by American psychologists R. Allen and Beatrice Gardner and studied by their colleague, Roger Fouts—and Koko, a gorilla trained by American psychologist Francine Patterson. But beyond showing that these primates may have had good memories, their rudimentary use of sign language gives no clear information about their ability to produce various combinations of symbols according to rules of grammar to express new things.
The question of animals’ use of language therefore remains controversial and gives rise to varying interpretations of certain observations. For example, in one case, a chimpanzee who had learned the sign for “water” and the sign for “bird” and then saw a swan swimming used the two signs together, supposedly to signify “water bird”. But scientists who do not believe in animal language argue that the chimpanzee may very well have been making two separate signs, one to designate the water and the other to designate the bird. They add that chimps who have been trained in sign language often use other symbol combinations that are illogical or unintelligible. Hence it is hard to say whether an association such as “water bird” reflects a flash of lucid language in chimpanzees or whether it is simply a set of coincidences observed by researchers who believe that chimpanzees are capable of a certain amount of language.
In any case, the least we can say is that any assertions about language in animals should be approached with extreme caution. The vocalizations used by our close relatives, the chimpanzees, to assert their dominance or to warn their group about threats are highly limited and are used in highly stereotyped situations, compared with human language. Thus no evidence currently exists to back the claim that communication in monkeys or dolphins approaches human language, with its nearly infinite possibilities for associating symbols to produce meanings.
One caveat, however: the ability to use language is not a prerequisite for the ability to think. Monkeys, like humans who are raised in isolation and never learn language, can still accomplish many things that require abstract reasoning. Many of the greatest creative minds in human history have reported that they got their best ideas from a kind of thinking that did not involve language. Albert Einstein, for example, said that he got many of his ideas about relativity by imagining himself riding horseback on a ray of light and looking around him at clocks and other objects as he did so.