PARIS — We're patient with dyslexics. Amused by people who have no sense of direction. Understanding toward the color blind. But there's no compassion for a person who can't recognize faces, who encounters someone on the street, for example, and doesn't realize that they've actually met before.

Instead, we interpret the person as being haughty, a bit snobbish perhaps. We recognize them, so they should be able to recognize us. Shouldn't they?

Not if the person has prosopagnosia, or face blindness, which is all the more perplexing given that most sufferers aren't fully aware of the handicap until quite late in life. At school, no one tests if children can recognize faces. And so the prosopagnosists, as they're called, often feel guilty. “I blamed myself," a journalist who prefers to remain anonymous confides. "It was as if I wasn't interested in other people, while in reality I am someone who's interested in others."

Put yourself in their shoes. How could they imagine that, for most people, the brain has this exceptional ability to distinguish, in less than a second, a familiar face from thousands of others, all fitted with noses, two eyes and a mouth?

In an attempt to understand this superpower — located in the right occipitotemporal area of the brain — researchers are studying those who don't have it. They make a distinction between prosopagnosia that can appear after brain damage, which can lead to a total loss of the ability to recognize familiar faces, even those of spouses or children, and the congenital form, which is characterized by difficulties with facial recognition rather than total inability.

To date there has only been limited research into the condition. One of the exceptions, as a 2006 study carried out by German students, suggests that prosopagnosia may affect 2.5% of the world's population.

Awkward encounters

Jane Goodall, the primate specialist, is a prosopagnosist. Her problems extend to monkey faces too, though at least they don't get ticked off as easily. When Goodall became aware of the atypical nature of her difficulties, she got in touch with the British neurologist Oliver Sacks. He told her not only that the handicap has a name, but that he too suffers from it. The neurologist even wrote about the condition in his book The Mind's Eye (2010).

Putting a name to her problem didn't stop Jane Goodall from feeling guilty. “It's humiliating because most people think I invent something elaborate as an excuse for not recognizing them because I'm not interested in them,” she says in her autobiography.

To compensate, Goodall pretends to know everybody and apologizes if someone tells her that in fact they haven't met before. “This leads to strange situations, but it's not worse than the other way around,” she says.

Another well known person with face blindness is French radio and television commentator Philippe Vandel, who says he has printed the Wikipedia page about prosopagnosia more than 20 times to share with people who don't believe the condition really exists.

In shows in which he takes part, Vandel notes the location of each person around the table. “In the world of television, this handicap is hard to manage! I'm often surrounded by people full of themselves who don't understand that you can't recognize them," he says. "And I find myself in parties with all these guys dressed in dark suits with white shirts and no ties.”

Photo: Pascal/Flickr

Developing strategies

Fads don't help prosopagnosists. For our anonymous journalist, the world is filled with lightly-bearded, dark-haired men, all interchangeable. At work, she's given up scrutinizing people (“it's no use”), but compensates for her face blindness by scribbling little clues in her reporter notebooks such as “big nose" or "blue sweater." “Restaurant waiter, nightclub bouncer, ticket inspector… I'll never be able to do any of these jobs,” she says.

Prosopagnosists often say some people are easier to recognize than others. Thomas Busigny, a neuropsychologist at the neurology unit of the Toulouse university hospital, confirms. “It's a question of prototypia: from the average gap between the eyes to the size of the eye, faces vary more or less from an average,” says Busigny, who has spent a decade studying face blindness.

“The one I prefer is [the French soccer player] Ribéry,” says Philippe Vandel, who generally has difficulty following soccer matches. “As soon as a player changes his hairstyle, I don't recognize him anymore.” Franck Ribéry is easier to recognize because has noticeable facial scars caused by a car accident he suffered as a a small child.

Concentrating on detail is typical of the compensatory strategies deployed by prosopagnosists. Jane Goodall says she looks for moles, even with chimpanzees. "These people pay close attention to peripheral signs,” says Busigny. “They notice the way people walk, look at their jewelry, hairstyles, clothes, handbags. One of my patients recognizes people thanks to their dogs or their cars.”

"I prefer staying at home"

For all their trouble recognizing faces, prosopagnosists have no trouble identifying voices. “My patients, who would never recognize me in the street, recognize me if I phone them,” Busigny observes.

Another well-known prosopagnosist is Bruno Patino, one of the leaders of France's state broadcaster France Télévisions, juggles with all sorts of strategies. When he was younger, he used to entertain groups of children, so he came up with cards with their favorite phrases. At work, he first printed out a chart with photographs of everybody, which he examined every morning (“it was no use”). Then, he memorized the office numbers.

But such tricks don't always work: at a taxi station, he mistook his father-in-law for a colleague. Often, relatives have to adapt.

Perhaps the best known prosopagnosist is U.S. film actor Brad Pitt, who made his face blindness “coming-out” in a recent interview with the magazine Esquire: “That's why I stay at home,” he said.

It's difficult to imagine how Pitt gets by in Hollywood parties. And yet for a prosopagnosist, acting in a movie, with all of its similar-looking characters and constant costume changes, is probably easier than watching one.