The following is from the script "Face Blindness" which originally aired on March 18, 2012 and was rebroadcast on Feb. 28, 2016. Lesley Stahl is the correspondent. Shari Finkelstein, producer.
Most of us take for granted that we can instantly recognize people we know by looking at their faces. It's so automatic, it almost sounds silly to even say it. Friends can put on a hat, cut their hair, and we still know them by their face. We can do this for thousands upon thousands of faces without ever giving it a moment's thought. But imagine for a second what life would be like if you couldn't, if your wife or husband looked like a stranger; you couldn't tell your kids apart; couldn't recognize yourself in a mirror. As we first reported a few years back, that's what life is like for people who suffer from a mysterious condition called face blindness, or prosopagnosia, that can make it nearly impossible to recognize or identify faces.
If you've never heard of face blindness, you're not alone -- chances are your doctor hasn't either. It's been unknown to most of the medical world until very recently. Hearing about it can feel a little like entering the twilight zone. But for people who are face blind, the condition is very real.
Jacob Hodes is one of them. He's 31 years old, he has a college degree, has had great jobs, and he seems perfectly normal -- just don't ask him to identify any faces.
Lesley Stahl: We're going to put up the first one, even very famous ones.
Jacob Hodes: [Picture of John Travolta] No idea.
We showed Jacob faces without hair, a pure test of facial recognition.
Jacob Hodes: [Will Smith] No.
Jacob Hodes: [Jimmy Carter] Nope. I can't say if I've ever seen that person.
He's seen Jimmy Carter plenty of times and he knows Michael Jordan too.
Jacob Hodes: Oh lord.
He just can't recognize their faces.
Jacob Hodes: [Elvis] Now that's just impossible.
Lesley Stahl: Can you describe my face? You're staring right at it.
Jacob Hodes: Yeah. High cheekbones. Light eyes.
Clearly Jacob could see my face, but he says if we happened to run into each other in a few days, he wouldn't know me from any other woman with short blonde hair.
Brad Duchaine: They meet somebody, they have a good time with them, they have a nice relationship. Then, a week later, they walk past them.
Brad Duchaine is a professor at Dartmouth College who has been studying face blindness for nearly 15 years. He says the hardest thing to understand is how people can see a familiar face but not recognize it. So he created a demonstration to give me a little taste. Faces turned upside down.
Brad Duchaine: So here are some famous faces. You're gonna be tempted to twist your head, but don't do it.
Lesley Stahl: OK.
Brad Duchaine: You know, can you--
Lesley Stahl: Boy, that is hard.
Brad Duchaine: Can you identify any of these people?
I was completely at a loss.
Lesley Stahl: You think I'd know all of these people?
Brad Duchaine: You've seen them all a lot.
Lesley Stahl: I don't know any of these people. I really don't.
Brad Duchaine: You wanna see 'em upright?
Lesley Stahl: Sure.
It was astonishing. With just that click, they became recognizable people before my eyes.
Lesley Stahl: I know John Travolta. I know Morley.
And there was Denzel Washington, Jennifer Aniston and Sandra Bullock. But the one that really got me was the young woman on the lower right, my daughter.
Lesley Stahl: I didn't know my own daughter?
Brad Duchaine: Yeah.
Lesley Stahl: I didn't know my own daughter. Wow.
Lesley Stahl: So is this-- am I getting a feeling for what people with face blindness have?
Brad Duchaine: This is, when you look at that, there's clearl-- there's a face there.
Lesley Stahl: Oh yeah.
Brad Duchaine: There are parts. There are eyes. There's mouth. But you just can't put it together.
Lesley Stahl: Wow. That's stunning. I feel terrible for them now.
Brad Duchaine: Yeah. It's really difficult.
And largely unknown. Prosopagnosia only got its name in the 1940s, when a couple of soldiers came back from World War II with head injuries and couldn't recognize their wife or parents. And it took another 50 years for science to discover that people could be born face blind, like Jacob Hodes and Jo Livingston, a retired teacher, Ben Dubrovsky, a software products designer, and Meg Novotny, a doctor.
Lesley Stahl: If I were your patient, we-- you'd spent a long time with me discussing a problem. I come back the next time.
Meg Novotny: Oh, no, no, no. You walk out to the window at the front and start checking out and I walk out of the room and I don't know who you are.
Lesley Stahl: Come on.
She relies on patient charts, she told us but there aren't any of those in Ben's office where lunch in the cafeteria can be tricky.
Ben Dubrovsky: I was sitting down at lunch having a discussion with someone about one of my projects and the guy across the table gets up from lunch and says, "God, that's really interesting. When you have that meeting can you invite me? Thanks. See ya." Who is it? I don't know.
Lesley Stahl: Who is it?
Ben Dubrovsky: I have no idea.
Lesley Stahl: Is it a memory issue?
Jacob Hodes: Not only.
Jo Livingston: The memory is never created.
Lesley Stahl: The face doesn't get put--
Jo Livingston: It doesn't get filed.
So they have to rely on other strategies to identify people: hair, body shape, the way people walk, their voice, even style of dress. But Jacob told us it can all fall apart when someone changes their hair, like a colleague named Sylvia who he couldn't find one day until she started putting her hair into her usual ponytail.
Jacob Hodes: And she like put it into the ponytail. And once it was in place that was Sylvia. It clicked. Then she took her hair back out of that ponytail.
Lesley Stahl: Right then and there?
Jacob Hodes: Yep. She just put it in and then took it out and--
Lesley Stahl: So she went from Sylvia, not Sylvia, Sylvia, not Sylvia?
Jacob Hodes: She disappeared.
Lesley Stahl: Come on.
Jacob Hodes: Yeah.
To him it was as though her face had changed into someone else's before his eyes.
Jacob Hodes: So now I'm confronted with this situation that got weird. Because I knew this person was Sylvia, but it didn't feel like Sylvia.
Faces mean so much to us: identity, beauty, character, a place to hang all our memories about a person. Faces have captivated artists forever, so it may surprise you to learn that the man who painted these faces, renowned portraitist Chuck Close is also face blind, and severely so.
Lesley Stahl: Let's say you went out to have dinner with somebody and then you saw her the next day--
Chuck Close: Wouldn't remember her.
And yet he has spent his career -- even after a collapsed spinal artery left him mostly paralyzed -- painting, well...
Lesley Stahl: Faces. Chuck Close has face blindness and he paints faces.
Chuck Close: The reason I think I was driven to it was to take images of people that matter to me and commit them to memory in the best way I can, which is to slow the whole process down, break it down into lots of little memorable pieces.
Which is exactly how he creates these works. He can't make sense of a whole face, so he works from a photograph with a grid on it, and translates what he sees -- square by square -- onto his canvas.
Lesley Stahl: Well, guess what we've done?
Chuck Close: I don't know.
Lesley Stahl: We put together a quiz for you.
We brought some of our famous faces along to show him...
Chuck Close: From the chin, I think it's-- um, Leno.
...and were surprised that he did pretty darn well.
Chuck Close: Well, from the lips, I think it's Tiger Woods.
Lesley Stahl: Yeah, well you're pretty good.
But of course not perfect...
Chuck Close: I don't have a clue.
Lesley Stahl: That's Tom Cruise.
Chuck Close: Right now, my guts are tied in knots because this very activity is the thing that makes me most nervous. Oh, now I have to figure out who this person is...
Because he isn't recognizing these faces the way most of us do. Every face is a puzzle he has to solve.
Chuck Close: What I'm thinking? You don't see too many people with just a mustache anymore, so that means it's probably somebody who's not alive. So if it's an African American of a certain age with a mustache, it might be Martin Luther King.
Lesley Stahl: You're amazing. You deduce, deduce, deduce. You're like Sherlock Holmes here.
Chuck Close: Yeah, this is how I get through life.
Of course he knew we were showing him famous faces. With our group, we threw in a trick one, a photo of Jo's daughter.
Lesley Stahl: Does anybody know who that is? Jo?
Jo Livingston: No.
Lesley Stahl: Jo, work on it, because it's somebody that Jo knows.
Jo Livingston: Well, it may be but nothing's coming.
Lesley Stahl: It's someone in your family.
But still she didn't get it...
Lesley Stahl: It's your daughter. Now can you see it? Is it clear now?
Jo Livingston: It is believable now.
We were baffled that a condition so extreme it could keep people from recognizing their own children could have been almost completely unknown until very recently. We spoke with Dr. Oliver Sacks, the chronicler of fascinating neurological conditions, who passed away last summer. He wrote about face blindness in his book, "The Mind's Eye."
[Oliver Sacks: It is with our faces that we face the world...]
Lesley Stahl: How do you explain that the medical world did not identify this problem?
Oliver Sacks: It is not usually a complaint of people. People do not bring it up. Many people who are color blind, do not know of it until they take an army medical. One sort of assumes that other people are the way one is.
Ben Dubrovsky: It never, ever, ever in my life occurred to me that people would look at a face and just get it like that.
Jo Livingston: I believed that I was not good with people but I had no idea of the reason. I just thought I was stupid.
Jo only learned there was such a thing as face blindness when she stumbled across this article, and came in to be tested in Duchaine's lab. A few hours after her second visit, in a bizarre coincidence, she and Duchaine ended up attending the same event.
Brad Duchaine: I kept placing my face in a position where she could see it.
Jo Livingston: I realized that one of the group was staring at me in a way that people don't normally.
Brad Duchaine: And so finally at one point I said, "Do you know who I am?"
Jo Livingston: "Ah."
Brad Duchaine: And she put it all together.
Duchaine had seen face blindness in action; Jo had seen the missed connections of her life.
Jo Livingston: If that had been anybody else, they would have been presumably furious, would not have spoken to me and would have probably never have spoken to me again. But I would never have known they were there.
Lesley Stahl: Yeah.
Jo Livingston: It made me realize, "How many times have I done this?"
Lesley Stahl: Right. How many friends have you offended? How many people aren't talking to you and you don't know why?
Jo Livingston: And we'll never know.
Oliver Sacks: People do think you may be snubbing them or stupid, or mad, or inattentive. That's why it's so important to recognize what one has. And to admit it.
Which is exactly what Sacks himself had just done -- written about the fact that he too was face blind.
[Oliver Sacks: I have had difficulty recognizing faces for as long as I can remember. My problem extends not only to my nearest and dearest, but also to myself. ]
Oliver Sacks: I've sometimes had the experience of apologizing to someone, and realizing it's a mirror.
Lesley Stahl: No.
Oliver Sacks: I have indeed.
Lesley Stahl: No. Because you didn't know it was you?
Oliver Sacks: I could see that it was a large, clumsy man with a beard. Now, I've now found a way of dealing with this. I have one special feature. I have rather large ears. If the large, clumsy man with a beard has extra large ears, it's probably me.
Lesley Stahl: I shouldn't be smiling, but it's funny.
Oliver Sacks: Well, it is. I mean, these things are both comic and serious.
And, surprisingly common. Recent studies show as many as 1 in 50 people may be face blind. And the search is on for clues inside their brains. We'll show you what the research is finding, plus, would you believe, super-recognizers...
Jennifer Jarett: I would say Mike Wallace.
Lesley Stahl: That is Mike Wallace!
...who never forget a face...
Jennifer Jarett: I don't even know how to get rid of people.
...when we come back.
No one knows what causes lifelong face blindness. It was discovered so recently, scientists are just beginning to unravel its secrets. And some of the clues are coming from people who once had normal face recognition, but lost it after suffering damage to part of the brain. And in an interesting twist, those people are also offering insight into the way the rest of us recognize faces. Imagine waking up after a trauma and not being able to recognize the people closest to you -- that's what happened to Colleen Castaldo.
Lesley Stahl: Up until the fall of 2009, did you have any trouble recognizing faces at all?
Colleen Castaldo: No, not at all.
Lesley Stahl: Just like everybody else?
Colleen Castaldo: Like everybody else, yeah.
That all changed late one night when Colleen had a seizure and was rushed to the hospital. Her doctors found a brain tumor and did surgery to remove it, but as she recovered, she started noticing that something wasn't right.
Colleen Castaldo: The nurses. I thought that I was meeting them each for the first time. And then, I would, you know, listen to them and think, I don't know, they were acting like they knew me already.
Lesley Stahl: Oh, disorienting.
She figured it was the medication, until her close friend Doreen came to visit wearing white, and Colleen assumed she was part of the medical staff.
Colleen Castaldo: I looked at her, I smiled and I turned back to my husband and started to talk to him, and he stood up and said, "Doreen." And I looked and thought, "Doreen?" And then, it hit me. I knew right then and there, this is the problem I had been having, that I--
Lesley Stahl: Faces.
Colleen Castaldo: I just-- yeah, faces.
Now even faces she knew well before...
Colleen Castaldo: [George Clooney] No.
Lesley Stahl: OK, well that's George Clooney.
Colleen Castaldo: Oh, wow. No, I wouldn't know that.
...are a mystery to her.
Colleen Castaldo: No, I don't know who that is. Who is it?
Lesley Stahl: The president.
Brad Duchaine showed me an MRI scan of Colleen's brain.
Lesley Stahl: Is that a hole in her brain?
Brad Duchaine: That's right. It's in the right temporal lobe.
Lesley Stahl: So back here.
Brad Duchaine That's right.
And the location of that hole where the tumor had been was a clue. If removing that area caused the loss of face recognition, could that be where all our brains process faces? It turns out that neuroscientists have been trying to figure out how it is that our brains recognize faces for decades.
Nancy Kanwisher: Face recognition is a very difficult problem, because all faces are basically the same.
MIT neuroscientist Nancy Kanwisher...
Nancy Kanwisher: There are these two roundish things here. There's this thing there. There's this thing there. They're all the same. And so discriminating one face from another is a very computationally difficult thing, because it's those subtle differences in the same basic structure that distinguish one thing from another.
And it is exactly those subtle differences face blind people like Jo Livingston miss.
Jo Livingston: I could describe anything I can put into words. Eye color, general overall shape, whether your ears stick out. But those things would bring it down perhaps from the population of the world to a few million.
So she could say this person has dark eyes, high cheekbones, an oval face, which would allow Jo to distinguish her from this person, but this face and this face? Impossible.
Jo Livingston: I can say what I can see. But I cannot say the micro-measurements that are what tell a normal person that it's you and not somebody of the same specification.
But how is it that the rest of us can perceive these two people as distinct individuals despite the similarities? An important clue comes from what we can't distinguish: as we saw earlier, faces upside down. Like these two Duchaine showed me, which look very similar.
Brad Duchaine: Maybe you don't even see that there's any difference.
Lesley Stahl: I see something different in the lower lip.
Brad Duchaine: Yeah.
Lesley Stahl: Eyes are a little different.
Brad Duchaine: But then, if I show them to you upright, so here's the one that you saw on the left there. Looks perfectly normal. And then--
Lesley Stahl: Oh!
Brad Duchaine: Here's the one you saw on the right, you saw upside-down.
Lesley Stahl: Oh my goodness.
The eyes and mouth in the photo on the right had been turned upside-down.
Brad Duchaine: And now the face looks really grotesque.
Lesley Stahl: Wow.
Brad Duchaine: But--
Lesley Stahl: But upside-down--
Brad Duchaine: Upside-down it's really hard to see that.
Nancy Kanwisher: If you look at a face upside-down, you're very bad at recognizing it. If you look at a word or an object or a scene, you can recognize it fine upside-down.
Lesley Stahl: So what did that tell you?
Nancy Kanwisher: It tells you that there's something very special about face recognition. It works in a very different way from recognition of everything else.
And that got Kanwisher wondering if there might be a part of the brain responsible just for seeing faces. She started putting people with normal face recognition into MRI scanners and watching what happens in their brains as they look at different images.
Lesley Stahl: This is what she's seeing?
Nancy Kanwisher: Yeah. This is what she's seeing.
Lesley Stahl: She's seeing faces.
Nancy Kanwisher: Exactly. And now she's seeing objects because we want to know not just what parts of the brain are active when you see faces, but what parts are more active when you see faces than when you see objects.
Kanwisher discovered that there was indeed a place in the brain that becomes very active when we look at faces.
Nancy Kanwisher: In every subject, boom, there was this nice, big response there. It was very exciting.
And it was right in the same area where Colleen's tumor had been. It's called the fusiform face area. So could that be what's missing in people with lifelong face blindness, like Jacob Hodes? Kanwisher put him in the scanner to find out.
Nancy Kanwisher: I really did not expect to see a fusiform face area.
Lesley Stahl: So you thought there'd be nothing there. Like as if instead of having a bullet go through it, he was just born without it.
Nancy Kanwisher: That's right. That's right.
Lesley Stahl: And?
Nancy Kanwisher: And we looked at the data and his face area was beautiful. It's textbook.
She scanned Jo, Ben and Meg as well, and they had fusiform face areas too.
Lesley Stahl: So what does that say to you?
Nancy Kanwisher: It tells us that the problem is not that this thing doesn't exist. There it is. But see, that's the fun of science. It's fun to be told you're just completely and totally wrong because now you have to go back and, you know, think anew.
And one thing she and other researchers are thinking about is a phenomenon as mystifying as face blindness -- its polar opposite - super-recognizers like Jennifer Jarett, who say they recognize almost every face they have ever seen.
Lesley Stahl: Waiters?
Jennifer Jarett: Yes.
Lesley Stahl: Salespeople?
Jennifer Jarett: Yes. Yes.
Lesley Stahl: Oh, like, of course.
Jennifer Jarett: Yes, absolutely. Yes. I'll be walking down the street and I'll see someone, and I'll think, "Oh retail." And then I'll remember, "Oh OK. That person works at-- as-- whatever store and that's where I s-- or they used to work at that store 10 years ago." And then I remember.
Lesley Stahl: 10 years ago?
Jennifer Jarett: Yes, yes.
Lesley Stahl: So they're-- it doesn't matter how far back you saw these people?
Jennifer Jarett: Yes, yes.
Lesley Stahl: So as long as you look at a person and take notice, they're in there?
Jennifer Jarett: I don't even know how to get rid of people.
Only a handful of super-recognizers have been discovered so far, and Duchaine and his colleagues had to come up with a whole new way to test them.
Brad Duchaine: So here are three faces here, which you're familiar with.
Lesley Stahl: I am?
It's called the "before they were famous test" because super-recognizers can also recognize faces as they change through time.
Brad Duchaine: Does that help at all?
Lesley Stahl: You sure I know that person?
Brad Duchaine: That's Dick Cheney.
Lesley Stahl: Oh my god. That's Dick Cheney?
He told me the top right was Richard Gere, and the bottom, Nancy Pelosi.
Lesley Stahl: Wow. Those three people have changed dramatically.
He even gave me a hint with this one: he's now an actor.
Lesley Stahl: And I'm supposed to know this actor?
Clearly, I was not a super-recognizer.
Brad Duchaine: That's George Clooney.
Lesley Stahl: Man. And these super-recognizers just know this?
Brad Duchaine: The supers are really good at recognizing these faces.
Jennifer Jarett: George Clooney.
Lesley Stahl: How could you tell that was George Clooney?
Jennifer Jarett: It just looked like George Clooney to me.
Jennifer Jarett: Oh, Prince Charles. Oh, Madonna. Michael Jordan.
Jennifer Jarett: Oh that's Kato Kaelin.
Lesley Stahl: The O.J. Simpson trial.
Lesley Stahl: Wow, you are good.
But we thought we had finally stumped her with this one. She said she only had a guess.
Jennifer Jarett: If I were to guess I would say Mike Wallace.
Lesley Stahl: That is Mike Wallace.
She recognized the late Mike Wallace as a 6-year-old!
Lesley Stahl: I don't even understand how you do that. I can't fathom it.
Jennifer Jarett: As people age I guess the aging process somehow in my brain just seems very sort of superficial. And, you know, as if someone gets a haircut you can still recognize them. It's still the same face to me. It's just the adult version.
So why is 60 years like a haircut to her, while face blind people can't recognize someone they just saw? A team of scientists at Harvard has begun scanning the brains of super-recognizers too, to see if they might yield any clues. The science of facial recognition is in its infancy. But new discoveries can't come fast enough for one last person we'd like you to meet --13-year-old Tim McDonough from Boston, who is severely face blind.
Lesley Stahl: Can you describe what it feels like when someone comes up? You know you're supposed to know who they are--
Tim McDonough: I usually just say, you know, "Hi, nice to see ya."
Lesley Stahl: So you sometimes pretend?
Tim McDonough: Yeah.
Lesley Stahl: You fake it?
Tim McDonough: I fake it, yeah.
[Researcher: So you think it's not your mom?
Tim McDonough: Yeah.
Researcher: OK, so that actually was your mom.]
Tim is working with the Harvard team to see if they can help him learn to recognize his mother's face. It's part of a pilot program to see if face blindness might someday be treatable. So far, it's not.
Tim McDonough: I just hope that nobody tries to talk to me because, if they do, they--
Lesley Stahl: They want to talk about something you've done with them, or something.
Tim McDonough: Yeah. And I don't know who they are.
Lesley Stahl: So it must be really hard to make friends.
Tim McDonough: It is, yeah. Takes me a while to make friends.
It turns out making friends can be tricky at both ends of the face recognition spectrum. Super-recognizers can seem like stalkers.
Jennifer Jarett: I would see someone, you know, weeks or months later at a party and people would say, "Oh, do you know each other?" And I'd say, "Yes." And the other person would say, "No." And I'd say, "No, don't you remember the first week of classes? You were walking to English class with someone..." And people would look at me really strangely and sort of uncomfortably, I think, a lot.
Jennifer says she's now learned to take her cues from others, ironically, just as face blind people do...
Jacob Hodes: I'll play this eye contact game where I'll wait. I'm not gonna really look at you, but I'll wait to see if you look at me. And then, "Oh, you look at me. Oh, look-- oh, hi."
Lesley Stahl: So you're always waiting for a cue from them?
Jacob Hodes: Yeah. So I'll hang back a little bit, which I don't wanna do.
Lesley Stahl: In any social situation, are you always a little anxious?
Oliver Sacks: I'm more than a little anxious. And I tend to keep my mouth closed before I make some awful blunder. Of course, another tactic, or strategy, is to smile at everybody.
That's what Chuck Close told us he does.
Chuck Close: You have to be really charming. If you are going to insult them by not remembering them, you just have to be extremely charming so that people don't hold this stuff against you.
Lesley Stahl: Do you feel now that you're missing out on something?
Ben Dubrovsky: Oh yeah.
Meg Novotny: Yeah.
Ben Dubrovsky: Definitely. I notice a loss.
Ben Dubrovsky: I understand someone by an abstraction. I put together a set of information that to me means mother or means Lesley.
Lesley Stahl: But it's not a visualization of a face.
Ben Dubrovsky: And the question, the thing that I wonder next, you know, is how does it affect even things like love?
Lesley Stahl: How does it?
Ben Dubrovsky: When people talk about love they say, "I carry the person with me. I carry their image with me." I don't carry their image. Does that mean I experience it differently? And how would I ever know? I don't know.
Jacob Hodes: There's a long tail of stuff that happens that you're missing. Connections you're not making.
Lesley Stahl: Still?
Jacob Hodes: Oh yeah. Yeah, yeah, yeah.
Meg Novotny: At least now we understand why.
Jacob Hodes: Yeah, right.
Meg Novotny: And it's therapeutic, but it doesn't fix it.