Here's a long article I read about people who don't recognize faces. Interesting.
Here's the beginning.
They can see your eyes, your nose, your mouth – and still not recognize your face. Now scientists say people with prosopagnosia may help unlock some of the deepest mysteries of the brain.
BILL CHOISSER WAS 48 when he first recognized himself. He was standing in his bathroom, looking in the mirror when it happened. A strand of hair fell down – he had been growing it out for the first time. The strand draped toward a nose. He understood that it was a nose, but then it hit him forcefully that it was his nose. He looked a little higher, stared into his own eyes, and saw … himself.
For most of his childhood, Choisser thought he was normal. He just assumed that nobody saw faces. But slowly, it dawned on him that he was different. Other people recognized their mothers on the street. He did not. During the 1970s, as a small-town lawyer in the Illinois Ozarks, he struggled to convince clients that he was competent even though he couldn't find them in court. He never greeted the judges when he passed them on the street – everyone looked similarly blank to him – and he developed a reputation for arrogance. His father, also a lawyer, told him to pay more attention. His mother grew distant from him. He felt like he lived in a ghost world. Not being able to see his own face left him feeling hollow.
One day in 1979, he quit, left town, and set out to find a better way of being in the world. At 32, he headed west and landed a job as a number cruncher at a construction firm in San Francisco. The job isolated him – he spent his days staring at formulas – but that was a good thing: He didn't have to talk to people much. With 1,500 miles between him and southern Illinois, he felt a measure of freedom. He started to wear colorful bandannas, and he let his hair grow. When it got long enough, he found that it helped him see himself. Before that, he'd had to deduce his presence: I'm the only one in the room, so that must be me in the mirror. Now that he had long hair and a wild-looking scarf on his head, he could recognize his image. He felt the beginnings of an identity.
It gave him the confidence to start seeing doctors. He wanted to know if there was something wrong with his brain. His vision was fine, they told him – 20/20. One doctor suggested he might have emotional problems and referred him to a psychiatrist. In the medical literature, there were a few reports of head-injury and stroke victims who'd lost their ability to recognize faces. No one, as far as the doctors knew, had ever been born with the condition.
Conventional medicine, in other words, got him nowhere. So Choisser posted a message about his experiences on a Usenet group devoted to people with neurological problems. His subject line was "Trouble Recognizing Faces." After a few months, in late 1996, he received a solitary reply. "Hello, Bill," the email began, "I read what you wrote, and I think I have what you have."
BRAD DUCHAINE WAS SO LOADED, he didn't realize he was plummeting to the ground. It was his 27th birthday party and the handsome Wisconsin native had been trying to have a good time. He'd had more than a few beers, grappled onto the roof to enjoy the beautiful Santa Barbara, California, sky, and fallen asleep. Now, inexplicably, he was falling. He smashed into the concrete driveway and his hip shattered. Luckily, the beer dulled the pain. He clawed his way to the living room and fell asleep among a few other unconscious revelers. Though no one knew it at the time, this guy – passed out, busted up, bleeding on the floor – was going to have a lasting impact on neuroscience.
Duchaine had started out enjoying himself too much as an undergrad and nearly flunked out of two colleges. He tried again at Marquette University in Milwaukee, and this time pulled it together. In the cold, boring Midwest nights, he settled down and did well, graduating summa cum laude in 1995. That got him into the cognitive psychology PhD program at UC Santa Barbara.
But the fall off the roof two years into his PhD coincided with a crack in his confidence. His dissertation was in shambles. He hadn't been able to find a suitable topic and was playing videogames until his thumbs hurt. Did he really think he could succeed as a neuroscientist? His parents were both midlevel managers at a paper company back in Wisconsin. Community college instructor was a more realistic goal.
But when Duchaine's parents visited their son in the summer of 1998, he didn't tell them any of this. The couple had invited an old friend to dinner at the Shoreline Beach Café, a seaside restaurant with tables right on the sand, and it didn't seem like the right time to reveal his doubts. Instead, over appetizers, talk turned to a presentation on unusual neurological cases that Duchaine had given to undergraduates earlier in the day. He was especially fascinated by a study of people who'd been hit on the head and lost their sense of direction or ability to perceive certain objects.
"I know a kid who doesn't recognize faces," the friend said.
"He had a stroke?" Duchaine asked. He knew that in a few rare cases – usually as a result of stroke or trauma – patients reported that they had lost the ability to recognize faces. Oliver Sacks' "man who mistook his wife for a hat" was the most famous example.
"No, he's always been that way," the friend replied.
Duchaine called the teenager's family a few days later. The boy's father told him that if he really wanted to learn more about the condition, he should check out a Yahoo group and Web site maintained by a guy in San Francisco named Bill Choisser. A whole community of these people were chatting online – that's how the teen discovered he wasn't the only one who had a problem with faces. Choisser had even begun to popularize a name for the condition: face blindness. If this were true – if there was a large, previously unidentified population with the condition – it would be a major discovery. Duchaine started to think he might make it as a neuroscientist after all.