By Harlan Lane

In 1973, when I was a visiting professor at the University of California, San Diego, a colleague drew my attention to something I must have seen before but had never really noticed.

Sitting on a terrace overlooking the Pacific, two people were deep in conversation—eyes locked, bodies inclined toward each other, alternating turns. But you couldn't hear a sound. They were communicating with their hands, faces, and bodies.

"What do you see?" my colleague asked. I couldn't be watching a language, I thought—language must be spoken and heard. I guessed I was seeing some kind of manual code based on English.

"Wrong," she said. "Those are Deaf people. We have discovered they are using a manual language with a vocabulary and a grammar all its own."

Astonished and excited, I began studying the Deaf children of Deaf parents, who had learned American Sign Language (as it would come to be called) as a native language. And I began to see how Deaf people were a target of prejudice and discrimination, even down to the prohibition of their language in the schools they attended.

There were no books on the history of the Deaf-World, as the Deaf call their culture, only chapters in two textbooks written by hearing people for the teachers of the Deaf. In essence, these chapters were a paean to hearing people's selfless devotion to the Deaf.

I was too familiar with the theft of black history to miss the point, so I decided to write a more accurate history of the Deaf. A dozen years later, When the Mind Hears was published by Random House.

My most recent book, published by Beacon Press in September 2004, is A Deaf Artist in Early America: The Worlds of John Brewster Jr. A New Englander who lived from 1766 to 1854, Brewster was arguably the best of all the early American portraitists who painted in the popular "plain style." The book looks at his life and art, as well as U.S. Deaf history during roughly the same period.

The American Deaf-World has major roots in Henniker, New Hampshire, and Martha's Vineyard, Massachusetts. The social fabric in these communities, including their use of sign language, differed markedly. It turns out these differences teach us a lot about how minority cultures are formed.

The first great American Deaf leader was Thomas Brown, born in Henniker in 1804. Brown was a slender, powerful man with a large head, gray eyes, and a facial tic from a childhood encounter with an ox. At eighteen, he enrolled at the American Asylum for the Education and Instruction of the Deaf and Dumb, in Hartford, Connecticut, where he studied under the two founders of American Deaf education, Laurent Clerc, a Deaf Frenchman, and Thomas Gallaudet, a hearing American.

At school, Brown met fellow student Mary Smith. Her family came from Martha's Vineyard, where Deaf people—especially in several remote communities "up island"—were quite common.

Mary's maternal grandmother and paternal grandfather were Deaf, but her mother and father were hearing. This was not unusual on the Vineyard; many Deaf children had parents who could hear, along with a mixture of hearing and Deaf relatives.

On the mainland, Deaf people married other Deaf people 80 percent of the time. On the Vineyard, it was nearly the reverse: Deaf people married hearing people 65 percent of the time. All this mixed marriage was made possible by the widespread use of sign language among the hearing people there. And what made that possible was no doubt the large number of families that included both Deaf and hearing children and adults.

Thomas and Mary married, and settled on his parents' farm in Henniker. The extended Brown family included many Deaf and a few hearing members. Thomas's father, Nahum, and his sister were Deaf; there were two Deaf nephews, who took Deaf wives. Mary gave birth to a Deaf son. Other Deaf couples lived in nearby towns. So it was quite a little community that worked and celebrated together, and attended the interpreted services at the local Congregational church.

As the nineteenth century approached its midpoint, Brown proposed the "mutes of America" meet in Hartford to show their gratitude to Gallaudet and Clerc. It would be the largest gathering of Deaf people assembled anywhere, anytime in history. Two hundred Deaf people, some from as far away as Virginia, converged for the ceremony, joining two hundred American Asylum pupils.

The following year, Deaf representatives from the New England states met for a week at the Browns' house to frame a constitution for the New England Gallaudet Association. Later, members talked about applying to Congress for a land grant out West and instituting a Deaf commonwealth (it never happened). There were more regional and national meetings. A Gallaudet monument, created exclusively by Deaf artists, was erected in Hartford.

A group consciousness had clearly begun to emerge among the Deaf. Brown and his associates saw the Deaf as a distinct group with a language and a way of life that needed to be fostered. Contemporary newspapers published by Deaf people called Brown the "patriarch of the silent tribe."

In stark contrast, accounts of life on Martha's Vineyard during the same era reveal no events or structures that set Deaf people apart from hearing people—no leaders, no gathering places, no organizations, no monuments.

What led to this extreme difference in group consciousness on the mainland and the Vineyard? The answer seems to be biology, a difference in the genetic basis of the two Deaf societies.

In dominant transmission of hereditary traits, which I believe occurred in Henniker, every generation is likely to contain Deaf children. About half of all children will probably be Deaf. And, within a small margin of statistical error, this turned out to be true in the Brown family.

But in recessive transmission of hereditary traits, which probably occurred on the Vineyard, a Deaf person may have cousins, uncles, aunts, or grandparents who are Deaf, but perhaps not immediate family. A Deaf person may readily have hearing parents, as Mary Smith did, or hearing children.

In such a setting, Deaf people may feel connected to an extended family and community, one that includes hearing people. But they may not feel like a distinct group or a link in the chain of Deaf heritage, stretching from the past down to the future.

That's because it takes a "them" for an "us" to develop. The blending of hearing and Deaf lives on the Vineyard, underpinned by genetics and strengthened by a shared language, discouraged seeing hearing people as "them."

Conversely, many members of the Henniker Deaf enclave had Deaf parents, grandparents, and great-grandparents, and the boundary between their sense of "us" and the surrounding hearing community was more sharply demarcated.

This tale of two places leaves us with two lessons. First, on the mid-nineteenth-century Vineyard, where Deaf people were integrated with hearing people and most people could sign, the Deaf were seldom seen as different, and never as handicapped.

Second, the rich legacy left by the early Deaf-World came not from an integrated community, but an enclosed one. Minority leaders often deplore an indifferent and estranged society that shows little interest in their culture and language. Yet Deaf history tells us that, paradoxically, minority consciousness and pride are fostered by majority estrangement, not by assimilation.

The history of the Deaf is the story of an ethnic group seeking acceptance of their language. It is a familiar and instructive theme if you realize, as three decades ago I did not, that language doesn't, by definition, have to be spoken and heard.

Harlan Lane is a Matthews Distinguished University Professor in the Department of Psychology.