Got a request for information about being faceblind today. Thought I'd post my response to the person's questions:
1: When you see a person you've never met before, do you see their face at all or is it just a blur? For example, if someone had say a scar or a facial piercing or bright blue eyes, would you be able to notice them?
Prosopagnosia, or faceblindness, isn't really about not being able to see things. I can see people's faces just fine. I can see a scar or facial piercing or blue eyes or anything. I see it all, and I can even memorize facts about such a face if I need to!
The best description that I've ever come up with for faceblindness is that it is this: There is a special region of the brain that is optimized for doing pattern recognition on faces. It is able to quickly and subconsciously evaluate all of the characteristics of a face and compare it against your memories of all the people you've ever met. For a person like myself, with faceblindness, we don't have this sort of "hardware optimization." We have to do everything in "software," ie. We have to use other parts of our brain to figure out who someone is.
Since these other parts of our brain aren't so optimized, they're not nearly as good. They work slowly, miss a lot of things, and are easily fooled. A close friend only has to put on unusual clothing, cut their hair, etc. to make it completely impossible for me to recognize them, despite the fact that I know them very well. For people I don't know as well, it takes far less for me to be unable to recognize them. Something as simple as a shift in mood, a hair style or color change, or something like that is enough to make someone completely unrecognizable to me.
Perhaps another way to look at it is that I can see all of these facial characteristics just fine. They just don't mean anything special to me, and even the closest people can look like complete strangers to me fairly easily.
2: How do you distinguish between people? Can you recognize voices or hair or skin color or anything?
For me, the big three characteristics that I use to identify people are context, personality, and large scale body characteristics.
So if I run into a short asian guy at work that's really exciteable, I'll know that's Gerry. If I run into a tall happy guy that wears bright colors and is always smiling, that's Bob. If I'm going on a date and a large bearded man comes up seeming to be laughing at the world, that's my boyfriend.
Context is huge. Take away context, and I'll generally completely lose my ability to recognize someone. A guy once tapped me on the shoulder at a supermarket and asked me if I needed help. It was actually a good friend of mine playing a joke on me, but because I didn't expect to see him, I didn't recognize him and thought he was genuinely an employee of the store.
Personality is also huge. So huge to me, that when a person is in a different mood, I can instantly tell. I'm very sensitive to changes in mood, and if someone came to me acting *very* different than normal, I'd run a chance of being unable to recognize them. Personality also influences the way people move, and I've become very adept at recognize people simply by the way they walk, swing their hands, play with their hair, and stuff like that.
And large-scale body characteristics. Stuff like long hair or short hair. Dark hair or light hair. Tall or short. Fat or skinny. Dark skin or light skin. Stuff like that. I'm not good at recognizing people in the middle, though, just on the extremes. Someone with average hair length, medium brown color, average height, average build, and light brown skin will be almost impossible for me to recognize, even after knowing them for a while. But make them pale and fat with short hair, or black, tall and skinny with long dark hair, and suddenly I find them very easy to recognize.
3: Do faces become more familiar the more you see them?
Not really. I become more adept at recognizing people's personalities in those faces though. I start to recognize the smiling bald guy that has a little smirk on his face, or the constantly depressed short woman. Stuff like that. Our brains aren't optimized to memorize these characteristics about people, so it takes considerably longer to learn stuff like this than it would for a normal person to recognize someone else. But over time, prosopagnosiacs learn to recognize people by various means. Just not by their face.
4: Were you born with your condition? If so, when did you realize that you had it?
As far as I know, yes, I was born with it. I realized I had it in college after a friend lead me to the "face blindness and stones" webpage. http://web.archive.org/web/20090525034533/http://www.prosopagnosia.com/main/stones/index.asp
I read that site and went "Yes! Holy shit! THAT is why I have so much trouble recognizing people and remembering faces!" It was an eye opening moment. I had started to suspect that something was different about me in high school, though, and recognized that I had more difficulty remembering faces than most people.
5: Lastly, (this one is kind of personal) how did/does faceblindness affect your relationships with others and/or your view of yourself, if at all?
Bill Choisser's online book goes into this in some detail: http://www.choisser.com/faceblind/
For myself, it has the strongest tendency to affect my ability to connect with people. It's fairly often that I find myself sabotaging potential relationships, both personal and professional, when I hit that inevitable moment of, "I'm sorry, who are you again?"
People are so used to being recognized, that they automatically assume that if you don't recognize them, you don't care about them. I've seen it so many times, my heart tears to even think about it. Imagine lovers, friends, and others being turned away when you looked and them and didn't know who they were. It's horrible, and it makes for a very lonely childhood. When you don't recognize the playground friend you made the day before, it makes it hard to makes friends at all.
As for view of myself? Not really. I guess I don't care about makeup as much as most women, since it makes my face look so very very different that it can freak me out. But that's pretty common amongst people with this condition.