Learning to read is so entwined in the normal course of child development that it is easy to assume that our brains are naturally wired for print literacy. But humans have been reading for fewer than 6,000 years (and literacy has been widespread for no more than a century and a half). The activity of reading itself alters the anatomy of the brain. In a report released in 2009 in the journal Nature, the neuroscientist Manuel Carreiras studies illiterate former guerrillas in Colombia who, after years of combat, had abandoned their weapons, left the jungle and rejoined civilization. Carreiras compares 20 adults who had recently completed a literacy program with 22 people who had not yet begun it. In M.R.I. scans of their brains, the newly literate subjects showed more gray matter in their angular gyri, an area crucial for language processing, and more white matter in part of the corpus callosum, which links the two hemispheres. Deficiencies in these regions were previously observed in dyslexics, and the study suggests that those brain patterns weren’t the cause of their illiteracy, as had been hypothesized, but a result.

There is no doubt that literacy changes brain circuitry, but how this reorganization affects our capacity for language is still a matter of debate. In moving from written to spoken language, the greatest consequences for blind people may not be cognitive but cultural — a loss much harder to avoid. In one of the few studies of blind people’s prose, Doug Brent, a professor of communication at the University of Calgary, and his wife, Diana Brent, a teacher of visually impaired students, analyzed stories by students who didn’t use Braille but rather composed on a regular keyboard and edited by listening to their words played aloud. One 16-year-old wrote a fictional story about a character named Mark who had “sleep bombs”:

He looked in the house windo that was his da windo his dad was walking around with a mask on he took it off he opend the windo and fell on his bed sleeping mark took two bombs and tosed them in the windo the popt his dad lept up but before he could grab the mask it explodedhe fell down asleep.

In describing this story and others like it, the Brents invoked the literary scholar Walter Ong, who argued that members of literate societies think differently than members of oral societies. The act of writing, Ong said — the ability to revisit your ideas and, in the process, refine them — transformed the shape of thought. The Brents characterized the writing of many audio-only readers as disorganized, “as if all of their ideas are crammed into a container, shaken and thrown randomly onto a sheet of paper like dice onto a table.” The beginnings and endings of sentences seem arbitrary, one thought emerging in the midst of another with a kind of breathless energy. The authors concluded, “It just doesn’t seem to reflect the qualities of organized sequence and complex thought that we value in a literate society.”

OUR DEFINITION of a literate society inevitably shifts as our tools for reading and writing evolve, but the brief history of literacy for blind people makes the prospect of change particularly fraught. Since the 1820s, when Louis Braille invented his writing system — so that blind people would no longer be “despised or patronized by condescending sighted people,” as he put it — there has always been, among blind people, a political and even moral dimension to learning to read. Braille is viewed by many as a mark of independence, a sign that blind people have moved away from an oral culture seen as primitive and isolating. In recent years, however, this narrative has been complicated. Schoolchildren in developed countries, like the U.S. and Britain, are now thought to have lower Braille literacy than those in developing ones, like Indonesia and Botswana, where there are few alternatives to Braille. Tim Connell, the managing director of an assistive-technology company in Australia, told me that he has heard this described as “one of the advantages of being poor.”

Braille readers do not deny that new reading technology has been transformative, but Braille looms so large in the mythology of blindness that it has assumed a kind of talismanic status. Those who have residual vision and still try to read print — very slowly or by holding the page an inch or two from their faces — are generally frowned upon by the National Federation of the Blind, which fashions itself as the leader of a civil rights movement for the blind. Its president, Marc Maurer, a voracious reader, compares Louis Braille to Abraham Lincoln. At the annual convention for the federation, held at a Detroit Marriott last July, I heard the mantra “listening is not literacy” repeated everywhere, from panels on the Braille crisis to conversations among middle-school girls. Horror stories circulating around the convention featured children who don’t know what a paragraph is or why we capitalize letters or that “happily ever after” is made up of three separate words.

Declaring your own illiteracy seemed to be a rite of passage. A vice president of the federation, Fredric Schroeder, served as commissioner of the Rehabilitation Services Administration under President Clinton and relies primarily on audio technologies. He was openly repentant about his lack of reading skills. “I am now over 50 years old, and it wasn’t until two months ago that I realized that ‘dissent,’ to disagree, is different than ‘descent,’ to lower something,” he told me. “I’m functionally illiterate. People say, ‘Oh, no, you’re not.’ Yes, I am. I’m sorry about it, but I’m not embarrassed to admit it.”

While people like Laura Sloate or the governor of New York, David A. Paterson, who also reads by listening, may be able to achieve without the help of Braille, their success requires accommodations that many cannot afford. Like Sloate, Paterson dictates his memos, and his staff members select pertinent newspaper articles for him and read them aloud on his voice mail every morning. (He calls himself “overassimilated” and told me that as a child he was “mainstreamed so much that I psychologically got the message that I’m not really supposed to be blind.”) Among people with fewer resources, Braille-readers tend to form the blind elite, in part because it is more plausible for a blind person to find work doing intellectual rather than manual labor.