February 14, 2007

Lots of us have encountered a person who never remembers who we are no matter how many times we meet and introduce ourselves. At some point, most of us start to get insulted -- how many times can you chalk it up to bad memory, anyway? But there's actually a medical condition that would completely explain this person's inability to recognize you, and it has nothing to do with the person being a jerk. It's called prosopagnosia, or face blindness, and researchers are starting to realize that it affects far more people than they previously thought.

People with prosopagnosia (from prosopon, Greek for "face," and "agnosia," which is the scientific word for "recognition impairment") can perceive facial features just fine; if they were looking at a face, they could describe to you what the eyes look like, how big the nose is, what color the lips are and whether there's a cleft in the chin. But they cannot retain a memory of these features. So when they see a face for the second, third or fiftieth time, it's like seeing it for the first time. They simply do not recognize it. In cases of severe prosopagnosia, people don't even recognize their own face when they look in the mirror. They might as well be looking at a stranger.

While science doesn't fully understand the disorder, they do know enough to draw some conclusions about where the problem comes from. There's actually an area of the brain that deals with the visual perception of facial features. When you're looking at a face, the fusiform gyrus, located in the temporal lobe, is stimulated. And most people, when they look at that face again, recognize it as something they have seen before. But people with face blindness do not. Researchers infer then that the problem has something to do with the fusiform gyrus itself or in the neural pathways that convey information from that area to other parts of the brain, like the occipital lobe, which processes visual information. Face blindness can result from damage to the brain from, say, a car accident or stroke, or a person can be born with it. Some research suggests that face blindness may be carried on a single gene, although no one has yet identified the gene or what it does.

Unless you have prosopagnosia, it's easy to forget how much we rely on facial recognition in our daily lives. How would you get through the work day if your co-workers looked like strangers at the start of every day? Would your friends find it off-putting if you had to ask their names when you met up for lunch? Would movies lose some of their appeal if you thought every woman in the movie with brown hair was the same character? What if someone came to your door and said, "It's Anne, your sister. Can I borrow $20 and pay you back tomorrow?" How would you confirm that this woman with the same hair color and body type as your sister was, in fact, Anne, if you were home alone?

In order to deal with these problems, people with face blindness have to find other cues to people's identities in order to function in daily life. If you had prosopagnosia, you might arrive at work every day and go around to your coworkers' desks and take notes on what everybody's wearing. You might set up verbal cues with your friends and family members so unscrupulous strangers couldn't take advantage of your disorder. If your son has a mole on his right hand, you might recognize him that way. For many people with severe forms of the disorder, TV shows and movies are pretty much out as viable entertainment sources -- it's just too hard to follow a plotline when there are a dozen central characters and you can't remember who anybody is from one scene to the next.

While the medical community one thought prosopagnosia was extremely rare, recent research suggests that as many as one in 50 people may suffer from some degree of face blindness. Extreme face blindness can be socially crippling, while milder forms may only result in occasional frustration or embarrassment. Prosopagnosia is just one of many recognition disorders. Other visual recognition disorders include agnostic aexia, color agnosia and object agnosia, in which the person is unable to recognize written words, colors and objects, respectively. There are also various auditory and tactile recognition disorders.

For more information on face blindness and related topics, check out the following links:

Sources

  • Abedin, Shahreen. "Face blindness not just skin deep." CNN.com. Feb 6, 2007. http://www.cnn.com/2007/HEALTH/conditions/02/ 02/face.blindness/index.html
  • "Agnosia." PsychNet-UK. http://www.psychnet-uk.com/dsm_iv/agnosia.htm
  • "Face blindness runs in families." NewScientist.com. Mar. 26, 2005. http://www.newscientist.com/article.ns?id=dn7174
  • Prosopagnosia Research Centre http://www.faceblind.org/research/