Many of us are aware of a condition known as face blindness where, because of damage by trauma or a stroke to a small section of the brain that handles facial recognition, a person cannot differentiate between faces, or cannot even see them. The most famous example was reported by Oliver Sacks in his book about the man who mistook his wife for a hat.
But I didn't know until today that people can be born with the disorder - a lot of people.
(I read about this in a story by Joshua Davis, first published in "Wired," in a collection called "The Best American Science Writing - 2007.)
The tale begins with a fellow who, in his early adulthood, began to realize that he was very different. He couldn't even recognize himself in a mirror, but grew up thinking that was normal, or at most a minor handicap. (He had gotten by all those years by memorizing voices and noting things like hair and posture.) Now he started going to doctors, who proved to be no help. They'd never heard of such a thing. So the guy went to an Internet usergroup for people with neurological problems. The message he posted was titled "Trouble Recognizing Faces." Before long, responses started coming in.
A young scientist, learning about a heretofore unknown mental ailment, was quick to begin a study, with a ready-made study group right there on the Web.
It turns out, according to two separate studies, the problem is hardly uncommon. One study found that of 1,600 people given face-recognition tests, 32 were severely impaired. In another study, by a German researcher, 17 of 680 high school and college students were diagnosed. That works out to roughly 2 percent of the population, or nearly 6 million Americans.
We've always known that eyewitness testimony in criminal cases can be unreliable, but sheesh.