A study of a deaf child's linguistic abilities is stirring up an ancient debate over the nature of language. Is the human brain uniquely programmed to make and learn languages or does it simply pick up on ordered structures perceived when a child is first exposed to speech?
The subject, a 9-year-old boy named Simon, is uniquely appropriate for the experiment of asking whether language is learned or innate because he learned an error-riddled form of American Sign Language from his parents, who are also deaf, and a quite different sign language, with different grammatical rules, at his school.
Despite the faulty teaching of American Sign Language, Simon signed the language with correct grammar, which the researchers see as evidence that he was drawing upon innate language ability.
The researchers studied Simon from the time he was 2 1/2 to the time he was 9. They reported that he had signed in American Sign Language with the correct grammar, even though he had learned incorrect grammar from his parents.
To the obvious objection that Simon may have seen other people signing correctly in American Sign Language, the researchers reply that his parents were the only people whom he had seen signing in American Sign Language, apart from his parents' friends, who also signed incorrectly. His parents and their friends learned American Sign Language only as teen-agers, an age at which languages are often learned inaccurately.
The investigators, Dr. Elissa L. Newport of the University of Rochester and Dr. Jenny L. Singleton of the University of Illinois, believe that Simon recognized complex patterns in the language on the basis of his parents' inconsistent use of patterns.
And, they say, Simon learned to use some complicated rules in ways that had eluded his parents. The research was presented in June at a meeting of the American Psychological Society in San Diego.
Dr. Newport said that the way Simon had deduced grammatical rules showed "exactly the kinds of things you would predict" from theories of how children develop language. But it has been very difficult to find evidence that these theories are correct.
Other investigators said they were intrigued by this case. Dr. Ursula Bellugi, a neuroscientist at the Salk Institute in La Jolla, Calif., said, "It has been hard to get really solid evidence of whether the brain is disposed in particular ways for learning languages." The story of Simon, she said, "is really exciting" because it is so scientifically clean. "I think it's very convincing," she added.
Dr. Susan Goldin-Meadow of the University of Chicago said, "I think their data are incontrovertible."
But Dr. Jean Berko Gleason of Boston University, who is the editor of the standard linguistics textbook "The Development of Language," said that she would not read so much into the case history.
Simon, she said, "seemed to pick up on the regularities of the language," but he did not invent language structure out of whole cloth. And the study is based on just a single child, she added. "It's always interesting even if one child does something, but you never know if he's showing universal tendencies," Dr. Berko Gleason said.
Simon's story is part of a centuries-long tradition of case studies of children who scientists hoped could help shed light on the question of whether language is innate and whether there is only a window of time, when children are maturing, in which it can be learned.
Researchers have studied feral children, who are called that because they grew up with only animals for company. They have studied abused children who had been kept isolated and deprived of human talk and companionship. They have studied deaf children who had not been taught to sign.
But these studies were not scientifically pure, researchers said. The feral children and abused children had so many other emotional and physical problems that it was impossible to say what was cause and what was effect. The deaf children developed a language so simple that some question whether it counts.
Simon, on the other hand, was loved and cherished and was taught a language by his parents. The only thing missing was consistently correct complex grammar and sentence structure.