The Language Instinct: How the Mind Creates Language (5 page)

Now take the sentence
A unicorn that is eating a flower is in the garden
. There are two
is
’s. Which gets moved? Obviously, not the first one hit by the scan; that would give you a very odd sentence:

But why can’t you move that
is?
Where did the simple procedure go wrong? The answer, Chomsky noted, comes from the basic design of language. Though sentences are strings of words, our mental algorithms for grammar do not pick out words by their linear positions, such as “first word,” “second word,” and so on. Rather, the algorithms group words into phrases, and phrases into even bigger phrases, and give each one a mental label, like “subject noun phrase” or “verb phrase.” The real rule for forming questions does not look for the first occurrence of the auxiliary word as one goes from left to right in the string; it looks for the auxiliary that comes after the phrase labeled as the subject. This phrase, containing the entire string of words
a unicorn that is eating a flower
, behaves as a single unit. The first
is
sits deeply buried in it, invisible to the question-forming rule. The second
is
, coming immediately after this subject noun phrase, is the one that is moved:

Chomsky reasoned that if the logic of language is wired into children, then the first time they are confronted with a sentence with two auxiliaries they should be capable of turning it into a question with the proper wording. This should be true even though the wrong rule, the one that scans the sentence as a linear string of words, is simpler and presumably easier to learn. And it should be true even though the sentences that would teach children that the linear rule is wrong and the structure-sensitive rule is right—questions with a second auxiliary embedded inside the subject phrase—are so rare as to be nonexistent in Motherese. Surely not every child learning English has heard Mother say
Is the doggie that is eating the flower in the garden?
For Chomsky, this kind of reasoning, which he calls “the argument from the poverty of the input,” is the primary justification for saying that the basic design of language is innate.

Chomsky’s claim was tested in an experiment with three-, four-, and five-year-olds at a daycare center by the psycholinguists Stephen Crain and Mineharu Nakayama. One of the experimenters controlled a doll of Jabba the Hutt, of
Star Wars
fame. The other coaxed the child to ask a set of questions, by saying, for example, “Ask Jabba if the boy who is unhappy is watching Mickey Mouse.” Jabba would inspect a picture and answer yes or no, but it was really the child who was being tested, not Jabba. The children cheerfully provided the appropriate questions, and, as Chomsky would have predicted, not a single one of them came up with an ungrammatical string like
Is the boy who unhappy is watching Mickey Mouse?
, which the simple linear rule would have produced.

Now, you may object that this does not show that children’s brains register the subject of a sentence. Perhaps the children were just going by the meanings of the words.
The man who is running
refers to a single actor playing a distinct role in the picture, and children could have been keeping track of which words are about particular actors, not which words belong to the subject noun phrase. But Crain and Nakayama anticipated the objection. Mixed into their list were commands like “Ask Jabba if it is raining in this picture.” The
it
of the sentence, of course, does not refer to anything; it is a dummy element that is there only to satisfy the rules of syntax, which demand a subject. But the English question rule treats it just like any other subject:
Is it raining?
Now, how do children cope with this meaningless placeholder? Perhaps they are as literal-minded as the Duck in
Alice’s Adventures in Wonderland:

But children are not ducks. Crain and Nakayama’s children replied,
Is it raining in this picture?
Similarly, they had no trouble forming question with other dummy subjects, as in “Ask Jabba if there is a snake in this picture,” or with subjects that are not things, as in “Ask Jabba if running is fun” and “Ask Jabba if love is good or bad.”

The universal constraints on grammatical rules also show that the basic form of language cannot be explained away as the inevitable outcome of a drive for usefulness. Many languages, widely scattered over the globe, have auxiliaries, and like English, many languages move the auxiliary to the front of the sentence to form questions and other constructions, always in a structure-dependent way. But this is not the only way one could design a question rule. One could just as effectively move the leftmost auxiliary in the string to the front, or flip the first and last words, or utter the entire sentence in mirror-reversed order (a trick that the human mind is capable of; some people learn to talk backwards to amuse themselves and amaze their friends). The particular ways that languages do form questions are arbitrary, species-wide conventions; we don’t find them in artificial systems like computer programming languages or the notation of mathematics. The universal plan underlying languages, with auxiliaries and inversion rules, nouns and verbs, subjects and objects, phrases and clauses, case and agreement, and so on, seems to suggest a commonality in the brains of speakers, because many other plans would have been just as useful. It is as if isolated inventors miraculously came up with identical standards for typewriter keyboards or Morse code or traffic signals.

Evidence corroborating the claim that the mind contains blueprints for grammatical rules comes, once again, out of the mouths of babes and sucklings. Take the English agreement suffix
-s
as in
He walks
. Agreement is an important process in many languages, but in modern English it is superfluous, a remnant of a richer system that flourished in Old English. If it were to disappear entirely, we would not miss it, any more than we miss the similar
-est
suffix in
Thou sayest
. But psychologically speaking, this frill does not come cheap. Any speaker commited to using it has to keep track of four details in every sentence uttered:

• whether the subject is in the third person or not:
  He walks
  versus
  I walk
  .
  

• whether the subject is singular or plural:
  He walks
  versus
  They walk
  .
  

• whether the action is present tense or not:
  He walks
  versus
  He walked
  .
  

• whether the action is habitual or going on at the moment of speaking (its “aspect”):
  He walks to school
  versus
  He is walking to school.
  

And all this work is needed just to use the suffix once one has learned it. To learn it in the first place, a child must ( 1 ) notice that verbs end in
-s
in some sentences but appear bare-ended in others, (2) begin a search for the grammatical causes of this variation (as opposed to just accepting it as part of the spice of life), and (3) not rest until those crucial factors—tense, aspect, and the number and person of the subject of the sentence—have been sifted out of the ocean of conceivable but irrelevant factors (like the number of syllables of the final word in the sentence, whether the object of a preposition is natural or man-made, and how warm it is when the sentence is uttered). Why would anyone bother?

But little children do bother. By the age of three and a half or earlier, they use the
-s
agreement suffix in more than ninety percent of the sentences that require it, and virtually never use it in the sentences that forbid it. This mastery is part of their grammar explosion, a period of several months in the third year of life during which children suddenly begin to speak in fluent sentences, respecting most of the fine points of their community’s spoken language. For example, a preschooler with the pseudonym Sarah, whose parents had only a high school education, can be seen obeying the English agreement rule, useless though it is, in complex sentences like the following:

Just as interestingly, Sarah could not have been simply imitating her parents, memorizing verbs with the
-s
’s pre-attached. Sarah some times uttered word forms that she could not possibly have heard from her parents:

She must, then, have created these forms herself, using an unconscious version of the English agreement rule. The very concept of imitation is suspect to begin with (if children are general imitators, why don’t they imitate their parents’ habit of sitting quietly in airplanes?), but sentences like these show clearly that language acquisition cannot be explained as a kind of imitation.

One step remains to complete the argument that language is a specific instinct, not just the clever solution to a problem thought up by a generally brainy species. If language is an instinct, it should have an identifiable seat in the brain, and perhaps even a special set of genes that help wire it into place. Disrupt these genes or neurons, and language should suffer while the other parts of intelligence carry on; spare them in an otherwise damaged brain, and you should have a retarded individual with intact language, a linguistic idiot savant. If, on the other hand, language is just the exercise of human smarts, we might expect that injuries and impairments would make people stupider across the board, including their language. The only pattern we would expect is that the more brain tissue that is damaged, the duller and less articulate the person should be.