The Language Instinct: How the Mind Creates Language

by Steven Pinker

  We might imagine that Hans and Fritz Faustkeil are told on Monday, “Don’t go near the water,” and that both go wading and are spanked for it. On Tuesday they are told, “Don’t play near the fire,” and again they disobey and are spanked. On Wednesday they are told, “Don’t tease the saber-tooth.” This time Hans understands the message, and he bears firmly in mind the consequences of disobedience. He prudently avoids the saber-tooth and escapes the spanking. Poor Fritz escapes the spanking, too, but for a very different reason.

  Even today accidental death is an important cause of mortality in early life, and parents who consistently spare the rod in other matters may be moved to violence when a child plays with electric wires or chases a ball into the street. Many of the accidental deaths of small children would probably have been avoided if the victims had understood and remembered verbal instructions and had been capable of effectively substituting verbal symbols for real experience. This might well have been true also under primitive conditions.

  Perhaps it is no coincidence that the vocabulary spurt and beginnings of grammar follow closely on the heels of the baby, quite literally—the ability to walk unaccompanied appears around fifteen months.

  Let’s complete our exploration of the linguistic life cycle. Everyone knows that it is much more difficult to learn a second language in adulthood than a first language in childhood. Most adults never master a foreign language, especially the phonology—hence the ubiquitous foreign accent. Their development often “fossilizes” into permanent error patterns that no teaching or correction can undo. Of course, there are great individual differences, which depend on effort, attitudes, amount of exposure, quality of teaching, and plain talent, but there seems to be a cap even for the best adults in the best circumstances. The actress Meryl Streep is renowned in the United States for her seemingly convincing accents, but I am told that in England, her British accent in Plenty was considered rather awful, and that her Australian accent in the movie about the dingo that ate the baby didn’t go over too well down there, either.

  Many explanations have been advanced for children’s superiority: they exploit Motherese, make errors unself-consciously, are more motivated to communicate, like to conform, are not xenophobic or set in their ways, and have no first language to interfere. But some of these accounts are unlikely, based on what we know about how language acquisition works. For example, children can learn a language without standard Motherese, they make few errors, and they get no feedback for the errors they do make. In any case, recent evidence is calling these social and motivational explanations into doubt. Holding every other factor constant, a key factor stands out: sheer age.

  People who immigrate after puberty provide some of the most compelling examples, even the apparent success stories. A few highly talented and motivated individuals master much of the grammar of a foreign language, but not its sound pattern. Henry Kissinger, who immigrated to the United States as a teenager, retains a frequently satirized German accent; his brother, a few years younger, has no accent. Ukrainian-born Joseph Conrad, whose first language was Polish, is considered one of the best writers in English in this century, but his accent was so thick his friends could barely understand him. Even the adults who succeed at grammar often depend on the conscious exercise of their considerable intellects, unlike children, to whom language acquisition just happens. Vladimir Nabokov, another brilliant writer in English, refused to lecture or be interviewed extemporaneously, insisting on writing out every word beforehand with the help of dictionaries and grammars. As he modestly explained, “I think like a genius, I write like a distinguished author, and I speak like a child.” And he had the benefit of being raised in part by an English-speaking nanny.

  More systematic evidence comes from the psychologist Elissa Newport and her colleagues. They tested Korean- and Chinese-born students and faculty at the University of Illinois who had spent at least ten years in the United States. The immigrants were given a list of 276 simple English sentences, half of them containing some grammatical error like The farmer bought two pig or The little boy is speak to a policeman. (The errors were errors with respect to the spoken vernacular, not “proper” written prose.) The immigrants who came to the United States between the ages of three and seven performed identically to American-born students. Those who arrived between the ages of eight and fifteen did increasingly worse the later they arrived, and those who arrived between seventeen and thirty-nine did the worst of all, and showed huge variability unrelated to their age of arrival.

  What about acquisition of the mother tongue? Cases in which people make it to puberty without having learned a language are rare, but they all point to the same conclusion. We saw in Chapter 2 that deaf people who are not exposed to sign language until adulthood never do as well as those who learned it as children. Among the wolf-children who are found in the woods or in the homes of psychotic parents after puberty, some develop words, and some, like “Genie,” discovered in 1970 at the age of thirteen and a half in a Los Angeles suburb, learn to produce immature, pidgin-like sentences:

  Mike paint.

  Applesauce buy store.

  Neal come happy; Neal not come sad.

  Genie have Momma have baby grow up.

  I like elephant eat peanut.

  But they are permanently incapable of mastering the full grammar of the language. In contrast, one child, Isabelle, was six and a half when she and her mute, brain-damaged mother escaped from the silent imprisonment of her grandfather’s house. A year and a half later she had acquired fifteen hundred to two thousand words and produced complex grammatical sentences like

  Why does the paste come out if one upsets the jar?

  What did Miss Mason say when you told her I cleaned my classroom?

  Do you go to Miss Mason’s school at the university?

  Obviously she was well on her way to learning English as successfully as anyone else; the tender age at which she began made all the difference.

  With unsuccessful learners like Genie, there is always a suspicion that the sensory deprivation and emotional scars sustained during the horrific confinement somehow interfered with their ability to learn. But recently a striking case of first language acquisition in a normal adult has surfaced. “Chelsea” was born deaf in a remote town in northern California. A series of inept doctors and clinicians diagnosed her as retarded to emotionally disturbed without recognizing her deafness (a common fate for many deaf children in the past). She grew up shy, dependent, and languageless but otherwise emotionally and neurologically normal, sheltered by a loving family who never believed she was retarded. At the age of thirty-one she was referred to an astonished neurologist, who had her fitted with hearing aids that improved her hearing to near-normal levels. Intensive therapy by a rehabilitative team has brought her to a point where she scores at a ten-year-old level on intelligence tests, knows two thousand words, holds a job in a veterinarian’s office, reads, writes, communicates, and has become social and independent. She has only one problem, which becomes apparent as soon as she opens her mouth:

  The small a the hat.

  Richard eat peppers hot.

  Orange Tim car in.

  Banana the eat.

  I Wanda be drive come.

  The boat sits water on.

  Breakfast eating girl.

  Combing hair the boy.

  The woman is bus the going.

  The girl is cone the ice cream shopping buying the man.

  Despite intensive training and impressive gains in other spheres, Chelsea’s syntax is bizarre.

  In sum, acquisition of a normal language is guaranteed for children up to the age of six, is steadily compromised from then until shortly after puberty, and is rare thereafter. Maturational changes in the brain, such as the decline in metabolic rate and number of neurons during the early school-age years, and the bottoming out of the number of synapses and metabolic rate around puberty, are plausible causes. We do know that the language-learning circuitry of the
brain is more plastic in childhood; children learn or recover language when the left hemisphere of the brain is damaged or even surgically removed (though not quite at normal levels), but comparable damage in an adult usually leads to permanent aphasia.

  “Critical periods” for specific kinds of learning are common in the animal kingdom. There are windows in development in which ducklings learn to follow large moving objects, kittens’ visual neurons become tuned to vertical, horizontal, and oblique lines, and white-crowned sparrows duplicate their fathers’ songs. But why should learning ever decline and fall? Why throw away such a useful skill?

  Critical periods seem paradoxical, but only because most of us have an incorrect understanding of the biology of organisms’ life histories. We tend to think that genes are like the blueprints in a factory and organisms are like the appliances that the factory turns out. Our picture is that during gestation, when the organism is built, it is permanently fitted with the parts it will carry throughout its lifetime. Children and teenagers and adults and old people have arms and legs and a heart because arms and legs and a heart were part of the infant’s factory-installed equipment. When a part vanishes for no reason, we are puzzled.

  But now try to think of the life cycle in a different way. Imagine that what the genes control is not a factory sending appliances into the world, but a machine shop in a thrifty theater company to which props and sets and materials periodically return to be dismantled and reassembled for the next production. At any point, different contraptions can come out of the shop, depending on current need. The most obvious biological illustration is metamorphosis. In insects, the genes build an eating machine, let it grow, build a container around it, dissolve it into a puddle of nutrients, and recycle them into a breeding machine. Even in humans, the sucking reflex disappears, teeth erupt twice, and a suite of secondary sexual characteristics emerge in a maturational schedule. Now complete the mental backflip. Think of metamorphosis and maturational emergence not as the exception but as the rule. The genes, shaped by natural selection, control bodies throughout the life span; designs hang around during the times of life that they are useful, not before or after. The reason that we have arms at age sixty is not because they have stuck around since birth, but because arms are as useful to a sixty-year-old as they were to a baby.

  This inversion (an exaggeration, but a useful one) flips the critical-period question with it. The question is no longer “Why does a learning ability disappear?” but “When is the learning ability needed?” We have already noted that the answer might be “As early as possible,” to allow the benefits of language to be enjoyed for as much of life as possible. Now note that learning a language—as opposed to using a language—is perfectly useful as a one-shot skill. Once the details of the local language have been acquired from the surrounding adults, any further ability to learn (aside from vocabulary) is superfluous. It is like borrowing a floppy disk drive to load a new computer with the software you will need, or borrowing a turntable to copy your old collection of LP’s onto tape; once you are done, the machines can be returned. So language-acquisition circuitry is not needed once it has been used; it should be dismantled if keeping it around incurs any costs. And it probably does incur costs. Metabolically, the brain is a pig. It consumes a fifth of the body’s oxygen and similarly large portions of its calories and phospholipids. Greedy neural tissue lying around beyond its point of usefulness is a good candidate for the recycling bin. James Hurford, the world’s only computational evolutionary linguist, has put these kinds of assumptions into a computer simulation of evolving humans, and finds that a critical period for language acquisition centered in early childhood is the inevitable outcome.

  Even if there is some utility to our learning a second language as adults, the critical period for language acquisition may have evolved as part of a larger fact of life: the increasing feebleness and vulnerability with advancing age that biologists call “senescence.” Common sense says that the body, like all machines, must wear out with use, but this is another misleading implication of the appliance metaphor. Organisms are self-replenishing, self-repairing systems, and there is no physical reason why we should not be biologically immortal, as in fact lineages of cancer cells used in laboratory research are. That would not mean that we would actually be immortal. Every day there is a certain probability that we will fall off a cliff, catch a virulent disease, be struck by lightning, or be murdered by a rival, and sooner or later one of those lightning bolts or bullets will have our name on it. The question is, is every day a lottery in which the odds of drawing a fatal ticket are the same, or do the odds get worse and worse the longer we play? Senescence is the bad news that the odds do change; elderly people are killed by falls and flus that their grandchildren easily survive. A major question in modern evolutionary biology is why this should be true, given that selection operates at every point of an organism’s life history. Why aren’t we built to be equally hale and hearty every day of our lives, so that we can pump out copies of ourselves indefinitely?

  The solution, from George Williams and P. B. Medawar, is ingenious. As natural selection designed organisms, it must have been faced with countless choices among features that involved different tradeoffs of costs and benefits at different ages. Some materials might be strong and light but wear out quickly, whereas others might be heavier but more durable. Some biochemical processes might deliver excellent products but leave a legacy of accumulating pollution within the body. There might be a metabolically expensive cellular repair mechanism that comes in most useful late in life when wear and tear have accumulated. What does natural selection do when faced with these tradeoffs? In general, it will favor an option with benefits to the young organism and costs to the old one over an option with the same average benefit spread out evenly over the life span. This asymmetry is rooted in the inherent asymmetry of death. If a lightning bolt kills a forty-year-old, there will be no fifty-year-old or sixty-year-old to worry about, but there will have been a twenty-year-old and a thirty-year-old. Any bodily feature designed for the benefit of the potential over-forty incarnations, at the expense of the under-forty incarnations, will have gone to waste. And the logic is the same for unforeseeable death at any age: the brute mathematical fact is that all things being equal, there is a better chance of being a young person than being an old person. So genes that strengthen young organisms at the expense of old organisms have the odds in their favor and will tend to accumulate over evolutionary timespans, whatever the bodily system, and the result is overall senescence.

  Thus language acquisition might be like other biological functions. The linguistic clumsiness of tourists and students might be the price we pay for the linguistic genius we displayed as babies, just as the decrepitude of age is the price we pay for the vigor of youth.

  Language Organs and Grammar Genes

  “Ability to Learn Grammar Laid to Gene by Researcher.” This 1992 headline appeared not in a supermarket tabloid but in an Associated Press news story, based on a report at the annual meeting of the principal scientific association in the United States. The report had summarized evidence that Specific Language Impairment runs in families, focusing on the British family we met in Chapter 2 in which the inheritance pattern is particularly clear. The syndicated columnists James J. Kilpatrick and Erma Bombeck were incredulous. Kilpatrick’s column began:

  BETTER GRAMMAR THROUGH GENETICS

  Researchers made a stunning announcement the other day at a meeting of the American Association for the Advancement of Science. Are you ready? Genetic biologists have identified the grammar gene.

  Yes! It appears from a news account that Steven Pinker of MIT and Myrna Gopnik of McGill University have solved a puzzle that has baffled teachers of English for years. Some pupils master grammar with no more than a few moans of protest. Others, given the same instruction, persist in saying that Susie invited her and I to the party. It is all a matter of heredity. This we can handle.

  A single dominant
gene, the biologists believe, controls the ability to learn grammar. A child who says “them marbles is mine” is not necessarily stupid. He has all his marbles. The child is simply a little short on chromosomes.

  It boggles the mind. Before long the researchers will isolate the gene that controls spelling…[the column continues]…neatness…. The read-a-book gene…a gene to turn down the boom box…another to turn off the TV…politeness…chores…homework…

  Bombeck wrote:

  POOR GRAMMAR? IT ARE IN THE GENES

  It was not much of a surprise to read that kids who are unable to learn grammar are missing a dominant gene…. At one time in his career, my husband taught high school English. He had 37 grammar-gene deficients in his class at one time. What do you think the odds of that happening are? They didn’t have a clue where they were. A comma could have been a petroglyph. A subjective complement was something you said to a friend when her hair came out right. A dangling participle was not their problem….

  Where is that class of young people today, you ask? They are all major sports figures, rock stars and television personalities who make millions spewing out words such as “bummer,” “radical” and “awesome” and thinking they are complete sentences.

  The syndicated columns, third-hand newspaper stories, editorial cartoons, and radio shows following the symposium gave me a quick education about how scientific discoveries get addled by journalists working under deadline pressure. To set the record straight: the discovery of the family with the inherited language disorder belongs to Gopnik; the reporter who generously shared the credit with me was confused by the fact that I chaired the session and thus introduced Gopnik to the audience. No grammar gene was identified; a defective gene was inferred, from the way the syndrome runs in the family. A single gene is thought to disrupt grammar, but that does not mean a single gene controls grammar. (Removing the distributor wire prevents a car from moving, but that does not mean a car is controlled by its distributor wire.) And of course, what is disrupted is the ability to converse normally in everyday English, not the ability to learn the standard written dialect in school.