The human brain is hardwired to recognize faces. But what if you can't?
EMILY KWONG, HOST:
You're listening to SHORT WAVE...
(SOUNDBITE OF MUSIC)
KWONG: ...From NPR.
I see faces everywhere.
(SOUNDBITE OF MUSIC)
KWONG: In fact, the human brain is hardwired to see them in things that don't have faces at all. Driving this is the fusiform face area, which is a part of our brain at the back, shaped like an almond or a lima bean that sits right behind our ears.
And for many people, the process of seeing a face and recognizing who it belongs to is pretty seamless. Sadie Dingfelder, though, always had trouble with this. And then one day, in her late 30s...
SADIE DINGFELDER: I was in the grocery store with my husband, and I was following him around, and I noticed he was just suddenly filling our cart with all this junk food, which is very out of character. He's just a food snob. And so I grabbed some peanut butter out of the cart, and I said, since when do you buy generic? And I just, like, looked at him, and he looked back at me, and his face was just this mask of horror. And all at once, I realized that he was not my husband. He was a random husband-shaped stranger.
(SOUNDBITE OF MUSIC)
KWONG: Sadie is a freelance science journalist. And she couldn't shake how strange this grocery store encounter was. She joined a clinical study on something called face blindness, led by Joseph DeGutis, a neuroscientist at Harvard Medical School and the VA Boston Healthcare System.
DINGFELDER: I expected that, when I joined this study, I was going to come out as, like, sort of below average. And then I came out, like, the worst of the worst. Like, I was really bad.
KWONG: He told you that you had the fusiform face area of a 12-year-old and the facial recognition ability of a, quote, "mediocre to below-average macaque."
DINGFELDER: (Laughter) Yeah. Yeah. I'm on the monkey level.
KWONG: Joseph told her she had two types of face blindness, or prosopagnosia, which makes it difficult for people to recognize the faces of those they know.
DINGFELDER: Now, the thing is, though, the word face blindness does confuse people because when people are trying to illustrate this, they'll make, like, fuzzy faces, and, you know, I see faces just as sharply as anyone else, but they don't hang together in the same way.
KWONG: In Sadie's case, it was hard for her to tell faces apart and hard for her to recall a rich memory of who someone is. After she learned this, Sadie kind of laughed off her results, but pretty quickly after...
DINGFELDER: I started to feel, like, a burning in my nose about then, and I was like, oh, my God, I'm going to cry. I was just mortified, and I just, like, had tears running down my face. But I had glasses, and I just threw on glasses, and I went straight home. I just didn't tell anyone.
KWONG: But it was information she couldn't run from. She thought about her whole life. The isolation of not recognizing people she knew or forgetting their names, feeling like people didn't want to hang out with her - it all began to click.
DINGFELDER: All of these long-running mysteries suddenly became clear or had, like, sort of a new bit of evidence to apply to them.
KWONG: Sadie is one of an estimated 10 million Americans who are faceblind. She has received even more diagnoses since then. Among them - aphantasia, which makes it hard to form mental images, and severely deficient autobiographical memory, which makes it hard to remember things about her own life.
DINGFELDER: My memory is very different from neurotypical memories, and I have no ability to do that sort of mental time travel. I have no sensory memories.
KWONG: So Sadie decided to write down her story, combining memoir with science in a new book called "Do I Know You?"
DINGFELDER: Everything in my life is just a story I may have read. I could have just read it about myself, basically.
(SOUNDBITE OF MUSIC)
DINGFELDER: And so, in some ways, that makes being a writer the perfect job for me.
KWONG: So today on the show, one writer's journey into the science of sight, memory and imagination and how she hopes to awaken those who read her book to consider everyone's point of view. I'm Emily Kwong, and you're listening to SHORT WAVE, the science podcast from NPR.
(SOUNDBITE OF MUSIC)
KWONG: OK, let's get into the science. Sadie, I want to dive a little deeper into facial recognition. And I have to share with you that, like, I had always taken it for granted.
DINGFELDER: Yeah.
KWONG: Why did humans develop this, like, ability to recognize each other?
DINGFELDER: I mean, it is astonishing that we have this whole chunk of brain devoted just to face recognition. And scientists have tracked it back to when human faces exploded in variability, and this seems to be about the same time that protohumans started living in hunter-gatherer societies that were called fission-fusion where you might leave your tribe and join another one for a while and then come back to your tribe. And in that sort of very complex society, you have to have the ability to remember faces for long, long periods of time and to recognize them very quickly.
KWONG: Right. And this ability has to do with the fusiform face area, a part of the brain that recognizes faces, like we said earlier. What does that part of our brain do?
DINGFELDER: Man, the fusiform face area is fascinating.
(SOUNDBITE OF MUSIC)
DINGFELDER: So it seems like we're born with a face template that seems to reside in that little almond-shaped chunk.
KWONG: Yeah.
DINGFELDER: This is according to scientists who study this - not me personally. And so if you have lights, and you shine it on the bellies of, like, pregnant mothers at about eight months, unborn fetuses will orient and track face shapes.
(SOUNDBITE OF MUSIC)
DINGFELDER: You're born with this template, and - you know, that's pretty basic, right?
KWONG: Which would be, like, the two eyes and the mouth - like, generic face.
DINGFELDER: Right.
KWONG: OK.
DINGFELDER: Right. The most generic possible face.
KWONG: Yeah.
DINGFELDER: And actually, at 3 months old, babies can distinguish between chimpanzee faces better than adults can.
KWONG: Wow. Yeah, and you say that, by 9 months, babies lose that. They're good at telling humans apart but not chimps anymore.
DINGFELDER: Yes. And so this is all a process of neural pruning, and you actually don't peak in your face recognition skills until your 30s. So it's this very subtle skill.
KWONG: And it's, like, happening without anyone even trying. But if a person has face blindness as you do, what is it like for you when you see a face?
DINGFELDER: I - you know, I believe - it will be hard to ever know this is true or not, but I think...
KWONG: Yeah.
DINGFELDER: ...I have a qualitatively different experience looking at faces than people with normal face recognition because, if you are looking at a face and you have all this information going into it...
KWONG: Yeah.
DINGFELDER: ...Then I think that probably you are fitting that face onto, like, a internal face template, and you're doing just a better job than I am.
And I think this actually goes hand in hand - there's a very famous portrait artist named Chuck Close who is faceblind. He was famous for gridding out faces just patch by patch by patch and making these huge-scale pictures. And I think that faces seem more fragmented to people who are face blind because people who are excellent face recognizers really take in the face as a whole. They can do it in one glance. It's amazing.
And it's - it turns out that faces are like the file folder for all the biographical information you have about someone. And if you don't have that representation in your memory, then that information will tend to get lost at the bottom of your filing cabinet. So at least for whatever type of face blind I am, I think that it does impair my ability to remember stuff people tell me about themselves. And so I've actually started to take notes, and I think it's really improved a lot of my relationships (laughter).
KWONG: On the science note, what kind of research has been done about face blindness?
DINGFELDER: There - I mean, it's amazing. There's a metric ton of research on face blindness.
(SOUNDBITE OF MUSIC)
DINGFELDER: But most of it is really very dense neuroscience because researchers have used what we've learned about face recognition and applied it to all object recognition, which is a huge, interesting, fascinating problem. You know, how do you recognize a chair is a chair? And how do you recognize the letter H is an H? And all these things.
But I think that the research that, really, I find compelling - it's more about the personal side of face blindness and how it affects people. I mean, there's something like 10 million Americans who are faceblind, and the vast majority of us do not have any idea that we're faceblind because if you've always been like this, then it's just what you're used to, even if it causes problems, and it's hard to know how much better other people are at it. And so I just really enjoy the research that shows that learning that you're face blind, people - this experience of having your life come into focus - it feels like a missing piece of a puzzle.
KWONG: Yeah, absolutely. I mean, in addition to having face blindness, you write about some other conditions that are yours. You are stereo blind, which - I'm oversimplifying this - is an inability to see depth with both eyes.
DINGFELDER: Yeah.
KWONG: And then you also write about having aphantasia, which is this condition that makes it difficult to imagine or visualize things in your mind.
DINGFELDER: Yeah.
KWONG: And what did realizing all of these things in the past few years catapult for you?
DINGFELDER: I did not realize how many flavors of human consciousness there were. You know, I spent a lot of time wondering what it's like to be my - a cat, for instance. It never occurred to me to also wonder what it's like to be a human, like a different - any - like, my husband or my best friend. People - it just didn't occur to me. I just assumed that their inner lives and perceptions were very similar to my own, and this is a mistake that almost everyone makes.
It's, like, advanced theory of mind, right? Theory of mind is understanding that other people have perspectives and might have different knowledge than you. But having - knowing that other people have a different way of processing information and awareness of their information processing is just wild, and it's really taught me to be more curious about other people and to be more understanding when people can't do things that I think are easy or vice versa.
KWONG: Yeah. Sadie, it's been such an absolute pleasure talking to you. I'm so looking forward to just your book hitting those shelves and kind of truly opening people's minds up to brains that are different than their own. And your brain's pretty fricking awesome, so...
DINGFELDER: Aw, thank you so much. Yours is, too.
KWONG: Oh, thank you.
(SOUNDBITE OF MUSIC)
KWONG: Sadie Dingfelder's new book, "Do I Know You?", is out now.
This episode was produced and fact-checked by Rachel Carlson. It was edited by our showrunner, Rebecca Ramirez. The audio engineer was Kwesi Lee. Beth Donovan is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. I'm Emily Kwong. Thanks for listening to SHORT WAVE, the science podcast from NPR.
(SOUNDBITE OF MUSIC)
KWONG: I also have no inner monologue.
DINGFELDER: (Gasps) You don't?
KWONG: I don't.
DINGFELDER: Oh, that's why we like talking out loud, so we know what we're thinking.
KWONG: It's, like, a purely impressionistic painting of emotions.
Copyright © 2024 NPR. All rights reserved. Visit our website terms of use and permissions pages at www.npr.org for further information.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.