Re-post: Prosopagnosia [slightly edited]
I first came across the phenomenon of Prosopagnosia, or face blindness, back when I read an article in Wired about the subject.
Basically it's the phenomenon of not being able to recognize faces. Not in the sense of not being good at remembering faces, but in the sense of not being able to recognize faces, including those of your own family and yourself.
Until recently it was thought it was only a phenomenon among people who damaged their brain through some kind of accident (the first well know example was apparently a soldier who was hit in the head, and after that was unable to recognize even his own wife), but now scientists have realized that it's much more widespread than that, and that people can suffer from this from birth. Brad Duchaine, a scientist studying this subject, estimates that 2 percent of the population is face blind.
One of the reasons why face blindness has gone undetected for so long, is the fact that people who suffer from it, are not aware how other people percept faces. This is of course not the case for people who get it later in life.
Another reason could also be that people are good at compensating. When I started needing glasses (when I was about 13 or 14), I learned to compensate for the lack of them, by being able to recognize people in the distance by how they moved. Since I stated wearing glasses I've mostly lost that ability again.
A most fascinating aspect of prosopagnosia is that it's very specific to faces. People who suffer from it, can recognize (and remember) other things as well as everyone else. This is probably due to the fact that faces are much more complex than other things, and demands more from the brain.
However, based on this abstract, it seems that at least some of the brain is able to recognize the person, yet the end result doesn't reflect this.
The reason for face blindness is probably genetic, since the trait has a inheritance pattern that is consistent with the trait being carried by a single gene.
Some further reading:
Face Blind - the original Wired article that got me interested in this subject.
Face blindness not just skin deep - CNN article about the subject.
Living in a world without faces - New Scientist podcast.
I’m Strange, You’re A Stranger - a blogpost from a blogger who suffers from prosopagnosia. The post is quite interesting, and also makes it clear that the problem is not only with human faces, but also animal faces.
I was doing some closet-cleaning the other week, and came across my portfolio of projects from when I took Commercial Art classes some years ago. One picture was an assignment: “Abstraction, select a natural object, create an abstract of that object”, cat, done in ink (dip-pen & pot of ink). I remember thinking about cats, and what qualities of the body shape define them as having “cat-ness”, and decided that it was the tail, the angularity of the limb joints, the pointed ears and the whiskers. But as I said, I tend to perceive things primarily by the mass and outline and by specific traits.
Most everyone did animals for that abstraction assignment, although the instructor pointed out that my drawing was the only one showing the animal from the back side, without the eyes. Mine was the only picture without a face!
Facebling.org - website of the Prosopagnosia Research Center Harvard University and University College London.