Bio: https://faculty-directory.dartmouth.edu/brad-duchaine
Prosopagnosia Research Center https://lab.faceblind.org/index.html
Imagine a world where everyone looks the same and you can’t recognize one person from another – even you own child! It sounds like a frightening episode from the “Twilight Zone” – but it’s just every day life for people with Prosopagnosia – better known as “Face Blindness”.
We humans use parts of our brains to see, process and recognize faces that’s different from recognizing anything else in our lives, which is not surprising when you consider how important faces are to understanding the situations we are in and the emotions of the people closest to us.
In this episode, Dr. Brad Duchaine, a professor of psychological and brain sciences at Dartmouth College and one of the world’s experts on face recognition, explains how how the face blind perceive the world, the strategies they use to mange their lives, and the rare few people who experience the almost unpronounceable condition of “prosopometamorphopsia.”
Plus, hear how “Super Recognizers” are using the opposite of face blindness to help fight crime.
Phil Stieg
I’m terrible with names, but I never forget a face. It’s a phrase we’ve all heard, and for many of us, it rings true. The human brain has a remarkable ability to recognize faces and decode identity, emotion, and intent almost instantly. But what happens when that ability breaks down? Dr. Brad Duchaine is a professor of psychological and brain sciences at Dartmouth College and one of the world’s leading researchers on how the brain processes faces. His work focuses on conditions that make it difficult or even impossible for people to recognize familiar faces, including those of close friends and family, and sometimes, even their own.
Today, we’ll learn from him why reading faces is so fundamental to being human and what studying face perception can teach us about how the brain builds identity, connection, and social understanding. Brad, thank you so much for being with us today.
Brad Duchaine
Thanks a lot for having me on.
Phil Stieg
So, I’m sure most people that are listening to this are thinking this is kind of a unique area. Why is facial recognition and tracking and understanding of emotional expression so important to us as human beings?
Brad Duchaine
The way I think about the face is that it’s kind of our badge. And as we’re walking around, the face is playing this really critical role in trying to broadcast who we are and how we feel about the situations that we’re in. And because of the importance that the face plays, it’s been critical for humans to have really sensitive face perception and to be able to extract a lot of information from these faces around them.
We get so much information from the face. When somebody walks into my office to figure out who that person is, I’m going to be likely looking at their face. If I want to know how they’re feeling, I’m collecting that information from their face. If I want to know what they’re thinking about, I’m looking at their eyes. And so there’s a wealth of information in the face.
Some people might be especially sensitive to the eyes, and others might be more sensitive to the mouth. And part of that depends on where people typically look on a face. We each have what’s called our preferred fixation location. And I might go, say down here on my nose, where whereas somebody else might tend to look up between the eyes.
I assume there are at least subtle differences between the way everybody sees a face I don’t think I’m very sensitive to noses, for example, and other people are. I also know that I’m particularly sensitive to hair. And so my wife and I will be watching TV and I’ll say, that person looks a lot like so and so. And she’ll say, no, they don’t. Their hair just looks alike. And that’s what you’re very dependent upon.
But in general, we’re extracting a number of different pieces of information from the face. Of course, we’re representing the parts that make up the face. We’re also representing the distances between those parts. And then, of course, we’re taking texture information from the skin, and we’re trying to put that all together. You can imagine that there’s a list maybe of 25 to 50 properties that you represent each time you see a face. And then when you do that, you compare that to lists that you’ve got for faces in memory. And if you get a close enough match, you say, ah, there’s Phil. I recognize that face.
Phil Stieg
That leads me to my next question. Then over time, you and I become friendly and familiar with each other. Does something change in my brain in terms of my perception of you?
Brad Duchaine
Absolutely. We developed particularly robust representations of faces that we’ve seen many times. We’re able to recognize those faces from different viewpoints in different lighting, often from really small amounts of information from the face, if we know that face well. And so, this is why, let’s say we’re talking about eyewitness testimony where somebody is in court and is saying, I saw that person at this particular event. Well, if they know that person, you can accept their eyewitness identification with confidence. On the other hand, if it’s a face that they’re not very familiar with, you should be very cautious about accepting that that’s actually the person they actually saw.
People just have a tough time when they haven’t seen the face dozens, maybe hundreds of times. And so each time I go through a line, say, at the airport, and there’s a TSA agent who’s looking at my ID and comparing it to my face, I know that that’s a really tough task. And people make errors in that all the time.
Phil Stieg
Other than describing the process, What fundamental question are you really trying to ask, you as a scientist?
Brad Duchaine
So we certainly do want to understand how face processing works. But the bigger question I’m interested in is what can understanding how face perception works tell us about the broader organization of the brain? And so one of the questions that got me interested in face perception almost 30 years ago now was trying to understand if there are mechanisms in the brain that are specialized for faces and faces only, and they’re not contributing to our ability to recognize cars and to recognize mugs and things like this, because that tells you something about sort of how finely tailored mechanisms are to particular functions. And I think over the last 30 years, there’s more and more evidence that face processing depends on highly specialized mechanisms. And you can imagine that’s true in a lot of different areas of the brain. But face perception is one of the areas that’s received the most attention within cognitive neuroscience.
Phil Stieg
Well, I would think just given the importance of facial recognition in the evolution of human relationships, that it would play a special role in our lives versus our ability to distinguish a car or a pretty dress or a nice pair of shoes or something like that.
Brad Duchaine
That’s exactly right. There’s been lots of interest in how these face processing systems develop. There have been studies in which people go into maternity wards and show faces to babies that are just a few minutes old. What you find when you present faces, they a ttend more to faces than to control stimuli. They’ll follow the face as it’s moving in front of them longer than they would follow, say, a scrambled face. And so that tells us that newborns come equipped with machinery in their visual systems ready to make sense of faces.
Phil Stieg
Everybodys’ heard about prosopagnosia, or “face blindness” although some tend to dismiss it forgetfulness. But it is real– isn’t it?
Brad Duchaine
Sure. So prosopagnosia is a condition which has been known about for quite some time. It got its name back in 1947. And in prosopagnosia, people have difficulty recognizing facial identity. And so they might go into their child’s daycare and maybe their child has changed clothes during the day, and they don’t know which child is theirs, so they’re having trouble recognizing faces that they’re highly familiar with. T here are some people who we work with who have trouble recognizing faces, but they’ll also have trouble recognizing their car in a parking lot. And so they’ve got broader problems.
There’s good reason to believe that the face processing system is a separate network from, say, what we use for object recognition, these are neighboring brain regions. And so it’s easy to imagine that if development doesn’t go right in the face processing network, neighboring regions might have been affected as well.
Phil Stieg
I was shocked to see that it’s between 6 and 8 million people with this disorder, which is 8 times the population of people with Parkinson’s disease, which has a much broader awareness in our public. Why is that?
Brad Duchaine
Developmental prosopagnosia is something that really only came to the fore around the turn of the century. And it was largely because the Internet allowed people with prosopagnosia to get in touch with researchers. And then people started doing research on these individuals.
Developmental prosopagnosia is a bit of a stealth condition, similar to colorblindness or color deficiency, I should probably call it. You don’t know how well other people are recognizing faces, and so it’s hard to gage how good your face recognition is compared to others. Sometimes it slaps you in the face. So I gave the example of going to a daycare and not recognizing which child is yours. All of a sudden, it becomes apparent to people in that sort of situation that their face recognition really is different from others, and maybe they’ll go home and Google face recognition problems. And it’s only been over the last 25 or so years that we’ve realized that there are a lot of people out there who really have a tough time recognizing faces.
Phil Steig
It’s got to be hard to deal with a condition like this – so what are the strategies that people with face blindness use to compensate?
Brad Duchaine
Yeah. People with prosopagnosia are great at sort of using other means to recognize people. Some people, for example, will tell many people who they encounter. They’ll try to explain to them, I’m prosopagnosic. I might have trouble recognizing you in the future. Give me a break if that happens. Others keep it to themselves because they found that people sometimes aren’t understanding.
I remember hearing from one person who mentioned that they tend to look at people’s teeth and will look at the particular idiosyncratic pattern of teeth that a person has. Others will tend to rely on shoes because a lot of people will tend to wear just a small set of shoes. And so they can use shoes to do this.
When they specialize in recognizing people from some cue other than the face, they will tend to find that part of themselves particularly important for their own identity. And there was a gentleman I worked with in San Francisco for many years (I wrote my dissertation on him) named Bill Shozer. And Bill had great trouble recognizing facial identity. Despite being a really intelligent guy. Went to MIT as an undergrad, ended up getting his JD but couldn’t do much when it came to facial information. But he was very good at recognizing people from their hair and recognizing people from their beards and their jeans that they would wear.
He grew up in a small town in the Ozarks in the 40s and 50s, where the kids wore the same jeans to school just about every day. And so Bill became a specialist at recognizing jeans. And jeans were very important to Bill’s identity. So Bill didn’t like not wearing his own jeans because he didn’t feel like he was himself. And that’s sort of. That was his badge for presenting himself to the world.
Phil Stieg
Can you give me an example of an individual that doesn’t recognize their own face and how that plays out?
Brad Duchaine
Sure, yeah. So people with prosopagnosia, it’s not uncommon for them to report difficulties recognizing their own face, either in the mirror or sometimes in photographs. I remember hearing from a woman, she was looking through photographs that were owned by a guy that she liked and she was going through these photographs and she kept seeing this woman who was with the man and she became jealous of this woman who was with the man. And she asked him, who’s this woman here? And he said, that’s you. And so she was failing to recognize herself.
The good news for her was that she found this woman attractive. So she got sort of the rare opportunity to have an unbiased assessment of her own facial attractiveness. And fortunately, she liked what she saw.
Phil Stieg
In your dealing with these people that have a difficult time recognizing faces, do they talk about a stigma? They don’t want to be spotted out. They don’t want to be known for having this deficiency. And do they see it as some disability, or is it just not important to them?
Brad Duchaine
See a wide range of reactions. But a lot of people certainly find it quite troubling, and that’s because people take it personally when we don’t recognize them. I think when people are not recognized, they feel that they weren’t important enough to the person who’s not recognized to them to sort of really burn a memory into their brain. And you can imagine the difficulties that people with prosopagnosia run into. You get into the elevator at work, and maybe your supervisor’s in the elevator, and you look right at them and you don’t acknowledge them. That doesn’t go over well.
Phil Stieg
Could you give an example in one of your patients that amplifies that concept?
Brad Duchaine
Sure, yeah. So I’ve heard from a number of people who we’ve worked with who’ve, look back and seen sort of lost romantic opportunities they’ve had. You know, they have a relationship with somebody and they encounter that person, but they don’t know that they’re seeing the person. And so then they just blank them. And it’s really hard to recover from that because, like I said earlier, people take it so personally.
Phil Stieg
I guess you could just play the game of, you know. And I am. I’m terrible with names. I personally never forget faces. And once I hear the story about the patient, I can put it together with a name. So, do they play that angle saying, oh, I’m just bad with names?
Brad Duchaine
I think sometimes they do. They also get frustrated in that when they explain to people the difficulties that they have, many people will say, oh, I understand. I’m terrible with names, too. And they’re trying to convey. No, it’s the previous step that I have a tough time with, just knowing that I’m looking at a familiar face.
Phil Stieg
So many of us have that episode in our lives. I see you, and I go, gosh, I know them from somewhere. Is that a face blindness or is that just a brain fart?
Brad Duchaine
I think that things like that happen to all of us from time to time. I had a funny event once where I was walking around a campus with somebody who was visiting my lab to be tested for prosopagnosia. And I saw a young woman who I thought was my research assistant on the street, and I said hi to her. It turned out it wasn’t her. It wasn’t my research assistant. And the prosopagnosic with me was really excited. And she said, oh, you’re prosopagnosic too? I said, no, I just failed to recognize that person there.
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Narrator
There are many people who casually claim that they “never forget a face”. But there is a tiny percentage of the population for whom this is literally true. They can never forget a face – no matter how hard they try. Welcome to the world of the “super recognizers”
SFX – London Traffic noise
Back in 2007 Detective Chief Inspector Mike Neville of the London Metropolitan Police was putting together an image database of unidentified criminals captured on security cameras. He asked officers to help identify these offenders. It became apparent that a small number of officers were making the vast majority of identifications.
After some tests by researchers at the University of Greenwich, they realized that some of the officers had an extraordinary ability for face recognition, — which is something of a superpower if you are trying to spot a criminal in a crowd – or identify looters at a riot seen on video.
Following the London Riots of 2011, DCI Neville formed the world’s first “Super Recognizers” Unit at New Scotland Yard, London, a team of over 200 people specially trained in matching faces in security video to police mug shots.
The term “super recognizers” was coined in 2009 by a team of researchers at Harvard and the University College in London which included this week’s guest Dr. Brad Duchaine.
They described Super Recognizers as the complete opposite of “face blind” prosopagnosics. They can recall seeing a face years – even decades after their initial meeting and can instantly identify pictures of famous people taken when they were small children.
But life as a super recognizer is not always easy. They often have to hide their special abilities in certain social situations. One super recognizer relates that he “learned to stop surprising people with bizarre comments like, ‘Hey, weren’t you at that so-and-so concert last fall… I recognize you’.” because people would get the impression that he was stalking them.
One woman had to stop using on-line dating apps because she would recognize people on the street whom she had “swiped left” on years ago and constantly had to fight the urge to walk up to them and ask … “So … are you still single?
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Phil Stieg
Another focus of your research is a condition that goes by the tongue-twister of a name — prosopometamorphopsia. From here on I’ll refer to it as PMO for short. Can you explain what this rare condition is?
Brad Duchaine
Prosopometamorphopsia, which I’ll also call PMO from here on out, is a condition in which people see distortions to the faces that they’re viewing. And these distortions, at least the people that we work with, tend to be very intense, so that they will see changes to the shape of the face, they’ll see changes to the color, the texture of the face. And often these distortions can even be dynamic. So while they’re looking at a face, they might be seeing an eye shifting its position.
Phil Stieg
Can you kind of go through the range of distortions that one can have or experience with this PMO?
Brad Duchaine
It’s a very wide range of distortions in that sort of. Anything that you and I can see in a face, you can imagine that could become distorted. There are some people who only see distortions in faces they’re familiar with, but not unfamiliar. So that suggests a real qualitative difference in the way that familiar, unfamiliar faces are processed.
We’ve got one woman that we work with in England who has such severe face perception distortions that she won’t be able to tell whether she’s looking at the face of a man or a woman, what the person’s race is, how old they are. And that’s because she’s seen such intense distance distortions to the face.
One time we showed her a photograph of a Ken doll, like Barbie’s friend Ken. She thought she was looking at a typical face. Another time we even showed her a photograph of a pig and she thought she was looking at a human face because it distorted so intensely on her.
Interestingly though, there’s a clear line on the neck that she’ll see below which the skin looks normal. Above it she’ll see discoloration, texture distortions. Below, the skin looks perfectly normal. And so there’s a real dividing line between what’s being processed in her face system and what’s being processed by other visual recognition mechanisms.
One of the participants whose distortions I could describe is somebody who we described in a paper a couple years ago. This participant’s initials are VS and we tend to use initials to hide people’s identities.
Up until 2020, VS perceived faces normally. And then one day he woke up. And ever since then, every face that VS sees in daily life is severely distorted. It’s a stable distortion. So the face doesn’t change as he looks at it, but what he sees is all the features are pulled back to the side. So imagine the ears being pulled back, the mouth is pulled back so it’s larger than it would be. The eyes and nose are stretched back. He also sees grooves. He sees three sets of grooves in each cheek as well as two grooves up in the forehead and then a small groove between the mouth and the chin. If he looks at faces from different viewpoints, these distortions remain stable. It’s the same sort of distortion. One of the things that’s particularly just–
Phil Stieg
To be clear, every face he looks at has that same distortion. If he looked at me, he’d see that distortion. If he looked at you, he would see that distortion.
Brad Duchaine
That’s exactly right
In a person who sees typical distortions, they see distortions on a 2D screen, they see them in daily life. And so if we try to make a visualization and have it on a computer screen and say, does this match what you see in daily life? Well, they’re going to be seeing distortions on that two dimensional representation of a face. So they can’t really say.
One of the unique aspects of VS’s distortions is that when he looks at two dimensional faces, so a face on a computer screen, a face on a television screen, the printed page, there’s no distortion in those two dimensional faces. From a vision science standpoint, that’s very surprising because of course, the face, whether it’s from a 2D or a 3D face, it’s landing on our retina. And my expectation would have been that face is going to be processed in the exact same way, but he processes them in qualitatively different ways.
Phil Stieg
I’m really curious about how individuals with these conditions function in day to day life. And most importantly, in terms of relationships. Where somebody was able to find love despite the condition that they had, or bond with their child despite the condition that they have.
Brad Duchaine
So in terms of presipagnosia, I can’t think of anybody who we’ve worked with where we thought there was sort of a reduced bond with their children. So I’m happy to report that. But it certainly does cause problems in one’s love life if you’re not recognizing one’s partner or somebody you’re trying to make turn into your partner. One thing that we’ve heard from a number of people is once their partner is tuned into the difficulties that they have, of course they’ll use strategies to make it easier for their partner who has difficulty recognizing faces. So if they’re at a cocktail party, they will say, “ah, here’s so and so. Remember them from this other party that we met them at?”
Spouses will also often wear distinctive clothing or say a hair accessory. So it’s easy for the person with prosopagnosia to recognize them. I think when it comes to pmo, though, it causes real challenges. So imagine if your partner’s face was distorting every time you looked at it. You don’t want to tell them that that’s how it’s looking. And I’ve heard from people who have experienced intense distortions for 20 years who never told their partner about it.
Phil Stieg
Hopefully they found it attractive.
Brad Duchaine
Well, occasionally we actually do hear from a few people who do see distorted faces and they say faces have actually become more attractive since my brain damage. But that’s not the norm, unfortunately. But I think about the woman I mentioned who we work with a lot in England. And for Aurora, one of the things that bothers her the most is that she’s not able to see her grandson’s face properly any longer. And she would love to see her grandson’s face as he grows up.
Phil Stieg
So I want to end on a happy note and you’ve got to provide it. Is there treatment for this?
Brad Duchaine
So when it comes to prosopagnosia so that people have difficulty recognizing facial identity, there have been a number of studies that have found that with computer training, pretty intense computer training, you can boost face recognition ability a little. Unfortunately, the gains are pretty modest and they don’t seem to persist after the training ends. And so at this point they’re not something that people would want to pursue.
One of the great things about studying people with PMO is that they have a lot of insight into their distortions and they might notice situations where they’re not experiencing distortions as intense as normal. And so we’ve looked into two different things that can reduce distortions for people. One is that certain Colors for some people with PMO influence the intensity of their distortions. And so we find that if people look through certain color filters, their distortions will either be reduced. So in the case of VS, who I talked about before, who only sees distortions on 3D faces, if he looks through a green filter, his distortions are greatly reduced. And in fact, he had glasses made that have lenses with a green tint. On the other hand, if he looks through a red filter, the distortions are amplified.
Other people actually show the reverse when it comes to green and red. And we don’t have an understanding about why. Why this is happening. And then there’s a more sort of a simpler way that we found that reduces distortions in somebody with PMO. If the face that they’re looking at has glasses on it, they find that their distortions are reduced. And so we work with a South African man who, if he’s out on a date with somebody, you know, he’ll say, no, no, no, keep your glasses on. You look great with your glasses.
Phil Stieg
Dr. Brad Duchaine, an expert on facial recognition from Dartmouth College, thank you so much for being with us and highlighting how facile the brain really is. Even if an individual can’t recognize somebody else’s face or they have a distorted view of that face, they still somehow can function in human life. That is so relevant and I think hopeful for individuals that no matter what their condition is, they still can try to lead a relatively normal life. Thank you so much.
Brad Duchaine
Thank you.
