The Language Instinct: How the Mind Creates Language

by Steven Pinker

  Elephants are the only living animals that possess this extraordinary organ. Their closest living terrestrial relative is the hyrax, a mammal that you would probably not be able to tell from a large guinea pig. Until now you have probably not given the uniqueness of the elephant’s trunk a moment’s thought. Certainly no biologist has made a fuss about it. But now imagine what might happen if some biologists were elephants. Obsessed with the unique place of the trunk in nature, they might ask how it could have evolved, given that no other organism has a trunk or anything like it. One school might try to think up ways to narrow the gap. They would first point out that the elephant and the hyrax share about 90% of their DNA and thus could not be all that different. They might say that the trunk must not be as complex as everyone thought; perhaps the number of muscles had been miscounted. They might further note that the hyrax really does have a trunk, but somehow it has been overlooked; after all, the hyrax does have nostrils. Though their attempts to train hyraxes to pick up objects with their nostrils have failed, some might trumpet their success at training the hyraxes to push toothpicks around with their tongues, noting that stacking tree trunks or drawing on blackboards differ from it only in degree. The opposite school, maintaining the uniqueness of the trunk, might insist that it appeared all at once in the offspring of a particular trunkless elephant ancestor, the product of a single dramatic mutation. Or they might say that the trunk somehow arose as an automatic by-product of the elephant’s having evolved a large head. They might add another paradox for trunk evolution: the trunk is absurdly more intricate and well coordinated than any ancestral elephant would have needed.

  These arguments might strike us as peculiar, but every one of them has been made by scientists of a different species about a complex organ that that species alone possesses, language. As we shall see in this chapter, Chomsky and some of his fiercest opponents agree on one thing: that a uniquely human language instinct seems to be incompatible with the modern Darwinian theory of evolution, in which complex biological systems arise by the gradual accumulation over generations of random genetic mutations that enhance reproductive success. Either there is no language instinct, or it must have evolved by other means. Since I have been trying to convince you that there is a language instinct but would certainly forgive you if you would rather believe Darwin than believe me, I would also like to convince you that you need not make that choice. Though we know few details about how the language instinct evolved, there is no reason to doubt that the principal explanation is the same as for any other complex instinct or organ, Darwin’s theory of natural selection.

  Language is obviously as different from other animals’ communication systems as the elephant’s trunk is different from other animals’ nostrils. Nonhuman communication systems are based on one of three designs: a finite repertory of calls (one for warnings of predators, one for claims to territory, and so on), a continuous analog signal that registers the magnitude of some state (the livelier the dance of the bee, the richer the food source that it is telling its hivemates about), or a series of random variations on a theme (a birdsong repeated with a new twist each time: Charlie Parker with feathers). As we have seen, human language has a very different design. The discrete combinatorial system called “grammar” makes human language infinite (there is no limit to the number of complex words or sentence in a language), digital (this infinity is achieved by rearranging discrete elements in particular orders and combinations, not by varying some signal along a continuum like the mercury in a thermometer), and compositional (each of the infinite combinations has a different meaning predictable from the meanings of its parts and the rules and principles arranging them).

  Even the seat of human language in the brain is special. The vocal calls of primates are controlled not by their cerebral cortex but by phylogenetically older neural structures in the brain stem and limbic systems, structures that are heavily involved in emotion. Human vocalizations other than language, like sobbing, laughing, moaning, and shouting in pain, are also controlled subcortically. Subcortical structures even control the swearing that follows the arrival of a hammer on a thumb, that emerges as an involuntary tic in Tourette’s syndrome, and that can survive as Broca’s aphasics’ only speech. Genuine language, as we saw in the preceding chapter, is seated in the cerebral cortex, primarily the left perisylvian region.

  Some psychologists believe that changes in the vocal organs and in the neural circuitry that produces and perceives speech sounds are the only aspects of language that evolved in our species. On this view, there are a few general learning abilities found throughout the animal kingdom, and they work most efficiently in humans. At some point in history language was invented and refined, and we have been learning it ever since. The idea that species-specific behavior is caused by anatomy and general intelligence is captured in the Gary Larson Far Side cartoon in which two bears hide behind a tree near a human couple relaxing on a blanket. One says: “C’mon! Look at these fangs!…Look at these claws!…You think we’re supposed to eat just honey and berries?”

  According to this view, chimpanzees are the second-best learners in the animal kingdom, so they should be able to acquire a language too, albeit a simpler one. All it takes is a teacher. In the 1930s and 1940s two psychologist couples adopted baby chimpanzees. The chimps became part of the family and learned to dress, use the toilet, brush their teeth, and wash the dishes. One of them, Gua, was raised alongside a boy of the same age but never spoke a word. The other, Viki, was given arduous training in speech, mainly by the foster parents’ moulding the puzzled chimp’s lips and tongue into the right shapes. With a lot of practice, and often with the help of her own hands, Viki learned to make three utterances that charitable listeners could hear as papa, mama, and cup, though she often confused them when she got excited. She could respond to some stereotyped formulas, like Kiss me and Bring me the dog, but stared blankly when asked to act out a novel combination like Kiss the dog.

  But Gua and Viki were at a disadvantage: they were forced to use their vocal apparatus, which was not designed for speech and which they could not voluntarily control. Beginning in the late 1960s, several famous projects claimed to have taught language to baby chimpanzees with the help of more user-friendly media. (Baby chimps are used because the adults are not the hairy clowns in overalls you see on television, but strong, vicious wild animals who have bitten fingers off several well-known psychologists.) Sarah learned to string magnetized plastic shapes on a board. Lana and Kanzi learned to press buttons with symbols on a large computer console or point to them on a portable tablet. Washoe and Koko (a gorilla) were said to have acquired American Sign Language. According to their trainers, these apes learned hundreds of words, strung them together in meaningful sentence, and coined new phrases, like water bird for a swan and cookie rock for a stale Danish. “Language is no longer the exclusive domain of man,” said Koko’s trainer, Francine (Penny) Patterson.

  These claims quickly captured the public’s imagination and were played up in popular science books and magazines and television programs like National Geographic, Nova, Sixty Minutes, and 20/20. Not only did the projects seem to consummate our age-old yearning to talk to the animals, but the photo opportunities of attractive women communing with apes, evocative of the beauty-and-the-beast archetype, were not lost on the popular media. Some of the projects were covered by People, Life, and Penthouse magazines, and they were fictionalized in a bad movie starring Holly Hunter called Animal Behavior and in a famous Pepsi commercial.

  Many scientists have also been captivated, seeing the projects as a healthy deflation of our species’ arrogant chauvinism. I have seen popular-science columns that list the acquisition of language by chimpanzees as one of the major scientific discoveries of the century. In a recent, widely excerpted book, Carl Sagan and Ann Druyan have used the ape language experiments as part of a call for us to reassess our place in nature:

  A sharp distinction between human beings and “animals” is e
ssential if we are to bend them to our will, make them work for us, wear them, eat them—without any disquieting tinges of guilt or regret. With untroubled consciences, we can render whole species extinct—as we do today to the tune of 100 speces a day. Their loss is of little import: Those beings, we tell ourselves, are not like us. An unbridgeable gap has thus a practical role to play beyond the mere stroking of human egos. Isn’t there much to be proud of in the lives of monkeys and apes? Shouldn’t we be glad to acknowledge a connection with Leakey, Imo, or Kanzi? Remember those macaques who would rather go hungry then profit from harming their fellows; might we have a more optimistic view of the human future if we were sure our ethics were up to their standards? And, viewed from this perspective, how shall we judge our treatment of monkeys and apes?

  This well-meaning but misguided reasoning could only have come from writers who are not biologists. Is it really “humility” for us to save species from extinction because we think they are like us? Or because they seem like a bunch of nice guys? What about all the creepy, nasty, selfish animals who do not remind us of ourselves, or our image of what we would like to be—can we go ahead and wipe them out? And Sagan and Druyan are no friends of the apes if they think the reason we should treat the apes fairly is that they can be taught human language. Like many other writers, Sagan and Druyan are far too credulous about the claims of the chimpanzee trainers.

  People who spend a lot of time with animals are prone to developing indulgent attitudes about their powers of communication. My great-aunt Bella insisted in all sincerity that her Siamese cat Rusty understood English. Many of the claims of the ape trainers were not much more scientific. Most of the trainers were schooled in the behaviorist tradition of B. F. Skinner and are ignorant of the study of language; they latched on to the most tenuous resemblance between chimp and child and proclaimed that their abilities are fundamentally the same. The more enthusiastic trainers went over the heads of scientists and made their engaging case directly to the public on the Tonight Show and National Geographic. Patterson in particular has found ways to excuse Koko’s performance on the grounds that the gorilla is fond of puns, jokes, metaphors, and mischievous lies. Generally the stronger the claims about the animal’s abilities, the skimpier the data made available to the scientific community for evaluation. Most of the trainers have refused all requests to share their raw data, and Washoe’s trainers, Beatrice and Alan Gardner, threatened to sue another researcher because he used frames of one of their films (the only raw data available to him) in a critical scientific article. That researcher, Herbert Terrance, together with the psychologists Lara Ann Petitto, Richard Sanders, and Tom Bever, had tried to teach ASL to one of Washoe’s relatives, whom they named Nim Chimpsky. They carefully tabulated and analyzed his signs, and Petitto, with the psychologist Mark Seidenberg, also scrutinized the videotapes and what published data there were on the other signing apes, whose abilities were similar to Nim’s. More recently, Joel Wallman has written a history of the topic called Aping Language. The moral of their investigation is: Don’t believe everything you hear on the Tonight Show.

  To begin with, the apes did not “learn American Sign Language.” This preposterous claim is based on the myth that ASL is a crude system of pantomimes and gestures rather than a full language with complex phonology, morphology, and syntax. In fact the apes had not learned any true ASL signs. The one deaf native signer on the Washoe team later made these candid remarks:

  Every time the chimp made a sign, we were supposed to write it down in the log…. They were always complaining because my log didn’t show enough signs. All the hearing people turned in logs with long lists of signs. They always saw more signs than I did…. I watched really carefully. The chimp’s hands were moving constantly. Maybe I missed something, but I don’t think so. I just wasn’t seeing any signs. The hearing people were logging every movement the chimp made as a sign. Every time the chimp put his finger in his mouth, they’d say “Oh, he’s making the sign for drink,” and they’d give him some milk…. When the chimp scratched itself, they’d record it as the sign for scratch…. When [the chimps] want something, they reach. Sometimes [the trainers would] say, “Oh, amazing, look at that, it’s exactly like the ASL sign for give!” It wasn’t.

  To arrive at their vocabulary counts in the hundreds, the investigators would also “translate” the chimps’ pointing as a sign for you, their hugging as a sign for hug, their picking, tickling, and kissing as signs for pick, tickle, and kiss. Often the same movement would be credited to the chimps as different “words,” depending on what the observers thought the appropriate word would be in the context. In the experiments in which the chimps interacted with a computer console, the key that the chimp had to press to initialize the computer was translated as the word please. Petitto estimates that with more standard criteria the true vocabulary count would be closer to 25 than 125.

  Actually, what the chimps were really doing was more interesting than what they were claimed to be doing. Jane Goodall, visiting the project, remarked to Terrace and Petitto that every one of Nim’s so-called signs was familiar to her from her observations of chimps in the wild. The chimps were relying heavily on the gestures in their natural repertoire, rather than learning true arbitrary ASL signs with their combinatorial phonological structure of hand shapes, motions, locations, and orientations. Such backsliding is common when humans train animals. Two enterprising students of B. F. Skinner, Keller and Marian Breland, took his principles for shaping the behavior of rats and pigeons with schedules of reward and turned them into a lucrative career of training circus animals. They recounted their experiences in a famous article called “The Misbehavior of Organisms,” a play on Skinner’s book The Behavior of Organisms. In some of their acts the animals were trained to insert poker chips in little juke boxes and vending machines for a food reward. Though the training schedules were the same for the various animals, their species-specific instincts bled through. The chickens spontaneously pecked at the chips, the pigs tossed and rooted them with their snouts, and the raccoons rubbed and washed them.

  The chimp’s abilities at anything one would want to call grammar were next to nil. Signs were not coordinated into the well-defined motion contours of ASL and were not inflected for aspect, agreement, and so on—a striking omission, since inflection is the primary means in ASL of conveying who did what to whom and many other kinds of information. The trainers frequently claim that the chimps have syntax, because pairs of signs are sometimes placed in one order more often than chance would predict, and because the brighter chimps can act out sequences like Would you please carry the cooler to Penny. But remember from the Loebner Prize competition (for the most convincing computer simulation of a conversational partner) how easy it is to fool people into thinking that their interlocutors have humanlike talents. To understand the request, the chimp could ignore the symbols would, you, please, carry, the, and to; all the chimp had to notice was the order of the two nouns (and in most of the tests, not even that, because it is more natural to carry a cooler to a person than a person to a cooler). True, some of the chimps can carry out these commands more reliably than a two-year-old child, but this says more about temperament than about grammar: the chimps are highly trained animal acts, and a two-year-old is a two-year-old.

  As far as spontaneous output is concerned, there is no comparison. Over several years of intensive training, the average length of the chimps’ “sentences” remains constant. With nothing more than exposure to speakers, the average length of a child’s sentences shoots off like a rocket. Recall that typical sentences from a two-year-old child are Look at that train Ursula brought and We going turn light on so you can’t see. Typical sentences from a language-trained chimp are:

  Nim eat Nim eat.

  Drink eat me Nim.

  Me gum me gum.

  Tickle me Nim play.

  Me eat me eat.

  Me banana you banana me you give.

  You me banana me banana you.<
br />
  Banana me me me eat.

  Give orange me give eat orange me eat orange give me eat orange give me you.

  These jumbles bear scant resemblance to children’s sentences. (By watching long enough, of course, one is bound to find random combinations in the chimps’ gesturing that can be given sensible interpretations, like water bird). But the strings do resemble animal behavior in the wild. The zoologist E. O. Wilson, summing up a survey of animal communication, remarked on its most striking property: animals, he said, are “repetitious to the point of inanity.”

  Even putting aside vocabulary, phonology, morphology, and syntax, what impresses one the most about chimpanzee signing is that fundamentally, deep down, chimps just don’t “get it.” They know that the trainers like them to sign and that signing often gets them what they want, but they never seem to feel in their bones what language is and how to use it. They do not take turns in conversation but instead blithely sign simultaneously with their partner, frequently off to the side or under a table rather than in the standardized signing space in front of the body. (Chimps also like to sign with their feet, but no one blames them for taking advantage of this anatomical gift.) The chimps seldom sign spontaneously; they have to be molded, drilled, and coerced. Many of their “sentences,” especially the ones showing systematic ordering, are direct imitations of what the trainer has just signed, or minor variants of a small number of formulas that they have been trained on thousands of times. They do not even clearly get the idea that a particular sign might refer to a kind of object. Most of the chimps’ object signs can refer to any aspect of the situation with which an object is typically associated. Toothbrush can mean “toothbrush,” “toothpaste,” “brushing teeth,” “I want my toothbrush,” or “It’s time for bed.” Juice can mean “juice,” “where juice is usually kept,” or “Take me to where the juice is kept.” Recall from Ellen Markman’s experiments in Chapter 5 that children use these “thematic” associations when sorting pictures into groups, but they ignore them when learning word meanings: to them, a dax is a dog or another dog, not a dog or its bone. Also, the chimps rarely make statements that comment on interesting objects or actions; virtually all their signs are demands for something they want, usually food or tickling. I cannot help but think of a moment with my two-year-old niece Eva that captures how different are the minds of child and chimp. One night the family was driving on an expressway, and when the adult conversation died down, a tiny voice from the back seat said, “Pink.” I followed her gaze, and on the horizon several miles away I could make out a pink neon sign. She was commenting on its color, just for the sake of commenting on its color.'