Short Wave - The Human Brain Is Hardwired To Recognize Faces. But What If You Can't?

Episode Date: June 26, 2024

Humans are hardwired to see faces — even in inanimate objects. We have a lima bean-shaped part of our brains dedicated to facial recognition. But this process isn't always straightforward. Science journalist Sadie Dingfelder is one of 10 million Americans who are face blind, or struggle to recognize the faces of people they know. In her new book, Do I Know You? she dives into this, as well as the science of memory and imagination. Want more episodes on the wonder of the human brain? Email us at [e-mail] pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. I see faces everywhere. In fact, the human brain is hardwired to see them and 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.

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 at him. 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.

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 de Goudis, a neuroscientist at Harvard Medical School and the VA Boston health care system. I expected that when I joined the study, I was going to come out as like, uh, sort of below average. And then I came out like the worst of the worst. Like I was really bad. 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.

Yeah, yeah. I'm on the monkey level. 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. 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. 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.

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. 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. All of these long-running mysteries suddenly became clear or had like sort of a new bit of evidence to apply to them. Sadie is one of an estimated 10 million Americans who are faceblind. She has received even more diagnoses since then. Among them, Afantasia, which makes it hard to form mental images and severely deficient autobiographical memory,

which makes it hard to remember things about her own life. 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. So, Sadie decided to write down her story, combining memoir with science in a new book called Do I Know You? Everything in my life is just a story. I may have read, I could have just read it about myself, basically. And so in some ways, that makes being a writer the perfect job for me. 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 Shorewave, the science podcast from NPR. Let's get into the science. Cedi, 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. Yeah. Why did humans develop this, like, ability to recognize each other? 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 proto-humans 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. 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? Man, the fusiform face area is fascinating. So it seems like we're born with a face template that seems to reside in that little almond shape chunk.

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. You're born with this template. And, you know, that's pretty basic, right? Which would be like the two eyes and the mouth, like generic face. Right. Okay.

Right. The most generic possible face. And actually at three months old, babies can distinguish between chimpanzee faces better than adults can. Wow. Yeah. And you say that by nine months, babies lose that. They're good at telling humans apart, but not chimps anymore. 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. 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?

I believe it will be hard to ever know this is true or not, but I think I have a qualitatively different experience of 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, then I think that probably you are fitting that face onto like an 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 gritting 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 faceblind 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. 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

faceblind 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. On the science note, what kind of research has been done about face blindness? I mean, it's amazing. There's a metric ton of research on face blindness. 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 blonde. 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 faceblind, people, this experience of having your life come into focus. It feels like a missing piece of a puzzle. 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.

Yeah. And then you also write about having a Fantasia, which is this condition that makes it difficult to, imagine or visualize things in your mind. Yeah. And what did realizing all of these things in the past few years catapult for you? I did not realize how many flavors of human consciousness there were. You know, I spend a lot of time wondering what it's like to be a cat, for instance. It never occurred to me to also wonder what it's like to be a human.

like a different, 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 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. 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 freaking awesome. Oh, thank you so much. Yours is too. Oh, thank you. 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 Kwayze 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 Shortwave. The Science Podcast. from NPR. I also have no inner monologue.

You don't? I don't. That's why we like talking out loud, so we know what we're thinking. It's like a purely impressionistic painting of emotions.