#27. I'm not rude, I'm just face blind (Prosopagnosia) - Dr. Tirta Susilo

Some people are poorer at identifying faces. Dr. Tirta Susilo, Senior Lecturer at Victoria University of Wellington, talks about what prosopagnosia is, what research tells us about how we perceive faces and objects, and what about those who have super face recognition abilities?

Chapters

• 0:00 Introduction
• 3:26 Face perception and face blindness
• 18:56 Specificity in perceiving
• 25:33 What do people with face blindness actually see?
• 32:24 Seeing faces in everything and super processors
• 44:16 Neurological side of face processing
• 50:48 Final Questions and wrap up

Transcript

0:05

All right, welcome everyone to the Smooth Brain Society. Today we have Dr. Tirtha Susilo. Is that how you pronounce it? Yes, perfect. Yeah, cool. On, he is a senior lecturer at Victoria University of Wellington and is on to talk about his work with regards to perception in particular face blindness. As always, we have a co-host today. Joining us again is Feral Bhadiani. She was on in our religion podcast, um, a few episodes ago. So welcome back Feral and welcome to the podcast. Awesome. So we'll just start where we start with every guest. And if you could give us a little bit of a background into how you got into your field of research, why you find this so fascinating. So a little bit about a background for our listeners. Yeah. Yes. I'll probably backtrack a little bit more because I stumbled onto psychology, onto science really. So I grew up in Indonesia. born and bred and I had no idea that one day I will make a living out of teaching and researching. So my undergraduate major in Indonesia was industrial engineering and I wasn't really a good student at the time. I was goofing around and had other priorities. But I did well enough so I graduated and then I tried out the real world. I worked in manufacturing and corporate finance for about a year. It didn't work out, so I didn't know what to do with my life. And so I remember one day I was going to a bookshop and I saw How the Mind Works by Steven Pinker. And so, I don't know, the title caught me at the time I tried to read it. I didn't really understand it, but I thought, hey, studying how the mind works sounds cool. And so I decided to go back to uni and study again, this time in Australia. So I went to Australia actually to do the. one year degree in psychology. And I did well enough and I got offered an honors scholarship. So I took it up and I worked with this woman Valerie Stone in Queensland who is an evolutionary psychologist actually at the time. She was doing all sorts of projects, one of which was on face perception. And And that was the only project on offer because I was the last student to arrive. It's like, this is the project you're going to work on. It's like, okay, I'll do it. So, and that brought me into the world of face perception and perception and vision kind of more generally. And then I continued with a PhD, uh, staying with the same topic, uh, learning more and more about face perception, psychophysics, experimental psychology, but neuroscience and in the last year of my PhD, there was this student in the, um, in the department. who had face blindness. And so as my supervisor, Eleanor McCone and myself ended up studying her, and we wrote a case report about her. And that brought me into the world of face blindness, which has remained with me ever since. So yeah, that's a bit of a roundabout answer, but that's the true story. Nice. So then what is face blindness for those who don't know? Yeah, yeah. So face blindness is also known as prosopagnosia. So that's a mouthful prosopagnosia. It's a Greek word prosopon means faces and agnosia means lack of knowledge or not knowing. So prosopagnosia or face blindness is a condition whereby someone is unable to recognize familiar faces. So faces that you've seen before, faces of, you know, family members, close friends. And this is unlike the occasional failure of face recognition that we all experience from time to time, right? So we see people on the machines like, oh, I can't really recognize the person or I can't put a name on it. It's nothing like that. This is much more severe and it happens frequently, even to faces that they're supposed to know because they interact with these faces all the time. Yes, super interesting. What I found really interesting in your introduction was you mentioned you worked in the field of evolutionary psychology briefly. So I wanted to know what are the evolutionary underpinnings to face blindness and if that is something that you've researched. Yeah, yeah. So I guess, you know, face blindness and face recognition more generally, I think, is one of the... research areas, I suppose, in visual perception that has attracted some evolutionary psychologists. And the reason is there seems to be specialized visual mechanisms that are used for faces, but not for recognizing other stimuli. And at the time, there's a lot of, this is about 20, 30, 40 years ago, there's a lot of debates and discussions concerning the variety of cognitive mechanisms that are... that our species as opposed inherited from our ancestors way back when. And face mechanisms seem like a good candidate for it, given how critical faces are for survival and all that. So that to me, I mean, that kind of brings in kind of the two sides of the equation where you have evolutionary biology and also visual perception and disorders in the case of face blindness. Cool. So then you mentioned that we seem to have a particular, what do you say, interest in, or evolutionary interest in, we say perceiving faces. So does that manifest biologically as well? So in the brain, do you see any differences in how people perceive faces versus- Yeah, yeah, of course. So there's a network of kind of regions across the occipital and the temporal lobe. that seem to be specialized for face processing. So if you use, you know, FMRI and you look at, you know, how these regions react when people see pictures of faces as opposed to control stimuli, these regions would respond much more strongly to faces. And this is also true in other primates. So Macaque Monkey is a great model for studying face processing because their visual system is very similar to that of humans. And they also have these, you know, of areas across their kind of exhibit temporal lobe, which contains cells. So these are individual neurons that are highly selective to faces. How do you experiment on these things? So what kind of research models do you actually use when you're trying to study face blindness? Yeah, so myself, I run mostly behavioral experiments. So I work with human participants who report having trouble recognizing faces. So I work with them. I give them kind of our standard battery for face blindness to see whether they meet the kind of the threshold for for prospec nosia, and if they do, I invite them to sit on a bunch of experiments, right? So one of my last experiments is on the distinction between the processing of facial identity and processing of facial expression. So faces are important because we not only use faces to recognize who people are, but we wanna know what they're feeling, what they're attending to, right? So there are all kinds of social information that we extract on faces. And I guess one of the key questions in prospecnosia is whether the impairments impact only the processing of identities, I don't know who you are, or does it also extend to the processing of other information from the face, right? So I ran a couple of behavioral studies looking at whether identity and expression processing can be dissociated. But other researchers, they use all kinds of tools. You know, the imaging is a popular one. You want to see whether the network of face regions, there's about a dozen of these areas on both hemispheres, whether they specialize in these different aspects of face processing. Maybe some areas are more specialized for identity processing, other areas for expression, for instance. In the monkey, of course, you could insert electrodes, and you could do single neuron or single cell recording. And so you could do that. go down a level and characterize how face processing works at the level of a single cell and kind of march through and see what happens in this area that seems to be kind of activated earlier because it's located closer to the back of the brain versus another area that seems to be activated later. So if you think about it, the whole network is like a factory where you have an assembly of processing, right? So what happens at the first stage and the second stage and so on. So there's a variety of methods that we use. And I think for the most part, the results converge, which is good, I guess, when you're doing, you know, mind and brain sciences, you want as many lines of evidence as possible going in the same direction. Really, really interesting. So can you shed some light on your findings or what are some of the costs, both evolutionary and current costs of face blindness? What is it that you have found through your research? Yeah, by cost you mean like what you know, how does it impact people who have it? Absolutely, both in the long term as a species and then both as present as an individual, if you know the answer. Yeah, yeah. I think the immediate cost is, you know, prospect knows you can be socially crippling, right? can't recognize people from their faces, then that you're at, you know, you have a big downside in terms of, you know, how you socially interact with people. So people who have prospecnocea usually try to come up with other routes to recognizing other people. So they pay more attention to your voice, for example, right? So when they first meet you and say, hey, you're a feral, and they try to pay close attention to how you speak and your mannerisms, right? And your hairstyle, your glasses, right? And they remember, okay, I met this, this... woman, Farrell, in Victoria, right? So when I see somebody like her on campus, I can use that contextual information. So that's the best they can do. But, you know, sometimes these cues, they fall short. And, you know, they just don't work if they happen to bump into you in a grocery store without context, and you change your hairstyle, and they'd be like, I'm sorry, you know, I have no idea who you are, until you start speaking. And so many people that we've worked with have reported all sorts of downsides in terms of wellbeing, in terms of limited work opportunities. You can imagine certain areas of our sectors where you have to interact with a lot of people and you kind of have to keep track of who's who and that would be difficult for them. So And the one common, I guess, anecdote that almost everybody with Prospect nosia mentions is that they often lost the plot when watching certain TV shows and movies. Especially those, you know, like, you know, you have a war movie with like, you know, 10 soldiers, all the kind of same style, same haircut, and they don't like which character does what, and they're just like, OK, there's no way for me to. make sense of this. In terms of evolution, I'm not quite sure actually. I mean, it's kind of interesting to think about how prosopagnosia can persist, right, assuming that it's been around for a long time. The, I guess, current estimates of the prevalence is about one to two percent, depending on where you draw the statistical line. And so maybe that is still within kind of the know, go on generations by generations without disrupting the kind of the whole balance of the population. So, but there is, I suppose I mentioned about, you know, monkey being a good model right before, and one, I think, difference that is often noted when we talk about human face recognition and monkey face recognition is that human face recognition seems to be more specialized for recognizing identities. just because we've seen hundreds, if not thousands of faces, not directly, just directly, but through magazines, TVs and things like that. Whereas for monkeys, I think they don't see that many, they live in small groups. So their face recognition is probably more specialized for tracking expression changes, right? So micro, oh, he's sort of like angry there. I picked it up, I wanna go away. I don't wanna get near him because he's gonna be. be awful or something like this. Maybe these systems, you know, they're kind of similar in many ways, but they've been kind of shaped, I suppose, slightly differently through, you know, evolution and also cultural demands, right, that are different for the different species. So based on that, how does prosopagnosia come about? So is it genetic or are they due to injuries or what's the reason? Yeah, that's a great question. So there are two types of prosopagnosia. For a long time, we thought prosopagnosia is acquired, right? So which means people used to be able to recognize faces and then they suffered some brain damage and then they lose their ability. recognize faces and it's noticeable because I know I used to be able to do this thing and now it's different. I can't do it anymore, right? So that for a long time, those are the only prospect nosia cases that were reported in the literature beginning in the 40s, I think. But in the last 20, 25 years, we've learned a lot about the other type of prospect nosia, which is lifelong. So... This is known as developmental prospecnoesia or congenital prospecnoesia. So people who have it, they've never been able to recognize faces. So for as long as they can remember, they always have trouble, even in childhood. So, you know, imagine, you know, you go to school and like everybody looks kind of, you know. unfamiliar and then you go home and you try to find your parents and you run to the wrong adult and kind of, you know, there are stories like that which are kind of comical but actually it's quite sad because, you know, people used to think all these kids they just don't get it. Maybe they have some learning disabilities but it's not learning disabilities. This is a very specific visual recognition disorder that they're having. So yeah, so the more common prosopagnosia is the lifelong one. That's the one that is estimated to impact about one in 50 people with two varying degrees. So at severity, of course, not everybody has severe prospec nosia. Some people have kind of milder version or moderate version. Yeah, you bring up learning disabilities is interesting because I was just thinking that if you're having because of a lack of face perception, if you're having issues with social interaction, it can easily be seen as other social interaction deficit disorders like autism or something. Yes. Yeah, yeah. And we know prospect knows yeah, it's not the same or it's not caused by autism. Right. So there's a couple of papers now. In fact, my, my latest paper is about that. So we look at the a population of people with ASD and we managed to dissociate their face recognition difficulties from difficulties that are experienced by people with prospec nosia. So there's a couple of reports now dissociating autism from prospec nosia. But early on, like, you know, when early reports about prospec nosia started to appear, people had the kind of natural suspicion maybe these are It's just a consequence of people not being socially adept, right? So maybe they're not paying attention to faces in the environment. So of course, if you don't pay attention, then you're not going to recognize people. And what's so, you know, what's so hard about that? But now we know that it's not due to lack of social attention or social motivation. It's not due to general memory problems, right? It's not just this people can't remember anything semantic about other people. And. And also it's not a general visual disorder because most people with prospecnosia can read just fine. They can see colors, they can recognize objects, they can navigate the environment and so on. So it seems to be a very specific form of visual recognition problems. I should say visual agnosia. I guess that's, you know, sometimes people think prospecnosia is a selective type of visual agnosia. So visual agnosia is a broader term whereby. Some people, mostly due to injury, have problems recognizing any objects at all. Right? So they can see, they, they can tell you that something is moving and what's moving is a red dot or something like that. But once you start presenting them with kind of more complex stimuli, like you showed them a picture of a car or something, then they say like, I have no idea what that is. I can tell you it's kind of blue. It has a curvy part here and there. The right side is bigger than the left part, but I don't know what it is. But then if you ask them, like, do you know what a car is for? Forget about the picture. And they say, oh, yeah, it's for driving. I have a car at home. So it's not that they don't know what a car is for. They don't lose their semantic knowledge about cars. And if you play them the sound of a car, they can tell you it's a car. So they can recognize a car through non-visual route. It's just a visual pathway for recognition is gone. So that's the case with people who have visual agnosia. Now prosopagnosia is like that. just for faces. More selective. Yeah. I had a two parted question. One, both of them build on what you said previously. Yeah, one which is, have you found any evidence for facial blindness? Because I cannot say the Greek word. Yes. Does it does it impact the ability to read emotions? Has it impacted that? And my second question is, You mentioned there being possible cultural differences and cultural pressures. Are there cultural differences that you have recorded or know about that affect facial blindness or even visual agnosia? Yeah, so those are both really good questions. So the first question, a minority of people with prosopagnosia have some trouble with expressions, but to a much lesser extent compared to their trouble with identity. most people who have prosopagnosia have no trouble recognizing expressions. So suggesting that, you know, in our brain there seems to be specialized mechanisms for processing facial identity that are separate from mechanisms for recognizing facial expressions, right? So the second question is about cultural pressures. Specific pressures I'm not aware of. I mean, as far as we know, prosopagnosia... is present everywhere around the globe. But it's interesting when you start talking about cultural variations, because in the face recognition literature, there's a well-known finding, just called the kind of the own race bias or the other race effect. You guys probably can imagine what it is. So if you grew up... among faces that have a similar structure. Let's say I grew up in Indonesia, around me, they're all Asian faces, right? So my visual system is pretty good at discriminating between Asian faces. And then I moved to Australia and suddenly my visual diet changes. Now there's a bunch of Caucasian faces around me. And Caucasian faces, they differ in ways that Asian faces are not. So take one example, eye color, right? So their eye color was this No idea. My visual systems never used to do this where it had to discriminate faces based on eye color. So I had to kind of learn that when I arrived in Australia and took me a couple of months until I'm okay. Now I can tell that these two white faces, these are different people, as opposed to just one person that I keep complaining. And so that phenomenon can interact with prospectrosia. So it could be... it could actually add to your prospectus. If you already have trouble recognizing faces, and now the faces are of different ethnicities and races, right? And they differ in terms of the features and so on, that you could have a double problem right there. I just wanted to quickly ask. So when Caucasian people are like, all Asian people look the same, is that not racist? Maybe. Well, there's about two answers, probably. I mean, some of them, maybe. I mean, but I think there's a visual perception answer to that whereby they're just being truthful. They say, well, you guys all look alike just because I'm not used to, you know, seeing and learning to discriminate between your faces. I'm not using the right features or dimensions, you know, in the kind of your face space that are optimal for discriminating between the faces. So you really look alike. I'm not just... I'm not pretending that you look the same. You really look the same as my visual system is concerned. Taking that one step further, then, if I looked at a particular object or particular variations of the same object again and again and again, or if there was enough of a diet for it, just like enough of a diet of Asian faces, per se, would my processing of those change in the brain as well? Would I have a new location specifically for that or something? Yeah, yeah. So this is a question about visual expertise, right? So some people develop certain experience with a particular class of objects. If you're a bird expert, for example, then you spend days on ends, right? Just watching birds and telling them apart and so on. And so the question is, what happens to your visual system when you do this? And there are changes. So there's a part of the brain that seems to be more malleable and it's adaptable for gaining expertise with visual objects that you have a lot of exposure to. But these are separate from the areas that are sensitive for faces. So way back when people debate about whether these are the same areas. And so the face areas are there just because we see faces a lot since day one. So maybe faces are not special. It's just because we have a lot of exposure to them. They look special. But it doesn't, I think it's safe to say now that doesn't seem to be. true. I think there's something special about faces, maybe the geometry, maybe the evolutionary significance, I mean, who knows what that we can dissociate in the brain, you know, faces versus these other objects of expertise. One, I guess one class of categories that is obviously different from faces is words and letters, right? I mean, we all had to learn to read when we were young, no region in the brain that is specialized for letters and words. But once we become, you know, an expert reader, we have what's called a visual word form area, which is located on the kind of left side of the brain, about a blueberry size region, I think, just tucked behind your ear. And that area seems really specialized for processing words and letters. Once you know how to read, of course. Well, In that case, you also mentioned, I remember, different levels of processing. So do people who have prosopagnosia or any sort of kind of object blindness as well, can they tell that something's there or something's wrong in an experimental condition or in real life? So you said that they seem to be better at detecting emotions without seeing a face. So can they kind of... vaguely tell what's going on? So this is kind of the first question people ask. If you have face blindness, what do you actually see when you look at a face, right? So they see the face. It's not like they're seeing a black hole or something like that. So sometimes the term face blindness can be misleading because they're not blind to the face, they see a face. But I guess the best illustration would be, and this is many people who have prospec nosia, they say this. My experience seeing faces is probably like your experience seeing faces when it's flipped upside down. So imagine looking at a face upside down, right? You still know it's a face, all the visual information is there, but suddenly you lose access to much of the social information. It's hard to recognize the person. You're not sure what expression is shown. You're not sure where the eye gaze is looking and all that. So they could tell you they're looking at a face. If they go slowly over the picture, they can tell you, oh, the nose is kind of bigger than average, you know, the left ear is asymmetric compared to the right ear and so on. But these, all these different features, different parts of the face, they don't add up and they don't come as a whole to give you that impression of, you know, the identity of the person or the expression that the person is showing. So that's probably the... the best way for people who don't have prospecnoesia to imagine what it's like when you have it. This may be, sorry. Yeah, no, go ahead. This may be like a silly question, but then how do people with facial blindness manage to have social relations like friends and even romantic relations like partners? So how is it that is navigated? Yeah, so it's tricky, like I said before. But again, I think I mentioned that prospect nosia comes in different severity, right, different levels. So if you have a, most people have a mild or moderate prospect nosia, which means that, you know, they can still recognize their partner, for example, or their spouse, you know, but not people that they just met, for example, newly learned faces would be difficult, but faces that they see again and again and again would be... okay with that. So I think that could help to some extent with kind of personal relationship and kind of as long as your social circle is small, small enough that you can you can manage it. But once it grows, then you have a you know, you have you have problems. But people with a more severe prosopagnosia, yeah, they really have a hard time. They just have to navigate the world without faces, so to speak, right? They can't even recognize themselves, some of them. So when they look at when they brush their teeth in the morning, they look at their face in the mirror, they can't recognize the face. Of course they know it's them because they're standing in there, but if you're looking at a face, it's like this face looks like an unfamiliar face, even though it's your face and you've seen it so many times. Right? So that's kind of, that's uncanny. I mean, I don't know how to imagine that. I'm just kind of like, this is just like a face, a random face that you see when you open a magazine or something. There you go. That's a face. So, yeah, it's wild. Wild. Yeah. And yeah, go ahead. So can you tell us a little bit more about the case study that you had done with the PhD student? Was it when you had, when you just introduced yourself, what kind of, how severe was their, her facial? Oh yeah, for her, yes. So she, hers was quite severe. And I think the study, in that study, we were interested in looking at this mechanism of face recognition, which I touched upon earlier, which we call kind of whole face processing. So it turns out with typical people, when we look at a face, we tend to process them as holes, right? So you look at a face, it's not like you go through, okay, I'm gonna recognize feral now, I'm gonna start with the left eye and then move to the nose. People don't do that. They look at your face, they take a snapshot and they say, that's feral, right? They get it. So they analyze the whole face as sort of like a one unit, one stimulus, right? So we wanted to see whether her prospectosia can be explained. by impairments of that process, whether she was unable to perceive and process faces as holes. And I think we found some good evidence of that. So it turns out that she relied more on kind of separate parts of the face when she tried to recognize the face. So if she lucked into a distinctive part of the face that gives away the identity, then she would be able to recognize the person. But as you can imagine that method of recognizing people is probably not robust. So yeah, she had a tough time, I think, socially speaking. But people come up with ingenious ways. So one of the probably more famous people who have prosopagnosia is Oliver Sacks. If you guys know about Oliver Sacks? No? So he's a famous, he passed away now, but he's a famous neurologist and he wrote a lot of books his wild cases, people with all kinds of interesting cognitive profiles. He himself had a lifelong prospec-mosia. And he used to host parties in his whatever New York apartment or something. But when he invited his guests, he told them to wear name tags, which I thought it was a smart way. So that way you can just tell who's who with recognizing. And I thought... from any prospect nosics we work with, that that's their strategy. That is to be open with people and say, hey, sorry, I have this condition. And so if I don't recognize you next time we meet, it's not because I don't care about you. I'm not paying attention. It's just, I have a visual shortcomings as far as face recognition goes. For those who don't know, one of his famous books is Man Who Mis-Took His Wife for a Hat. Oh. I have heard about that book. Yes. So that's Oliver Sacks. Yes. So that's the, that's the, uh, the author. I think he, uh, that's, that's probably his most famous book, The Man Who Mistook His Wife for a Hat. Uh, and then, I mean, he wrote, I don't know, a dozen of books, or probably more. I think there's one book that is called The Mind's Eye, I think. And in that book, there's a chapter about face blindness and he told his own story, living, living with it and failing to recognize his own face in a mirror. So yeah, he had a severe one. He had a severe, um. type of prospectrosia. Well, we're talking about not being able to process faces. Can I ask about the flip side where you kind of see faces in everyday objects and things like that? Um, where does that come into the whole processing spectrum? Yeah. Yes. So, so that's the, that's the one word answer to it. So there are two, actually there are two flip sides. So, and I'll, one is like you said, you know, our tendency to, to see faces when there's none. And the other is there are people who are actually the opposite, have the opposite of Prospect Nozia. So people who are called the super recognizers. So these are people who are really, really good at recognizing faces. Right. So I'll talk about that a bit later. But because your question is about seeing illusory faces. I think the experience is called pareidolia or something where you have this experience of seeing faces in Mars, faces in the clouds and things like that. So, yeah, so I guess one answer is that, you know, Again, faces are important. If we think about it in evolution terms, if you want to make an error, it's better that you have a false alarm of thinking a face is there rather than not detecting a real face when it's there. So I think it makes sense in terms of the cost benefit to build a system that is super sensitive to detecting face-like features in the environment. And that seems to be what happens. So In the last five to 10 years, I think there's been a search of studies looking at whether processing of illusory faces are similar to processing of real faces. And for the most part, I think the answer is yes. So these illusory faces seem also to be processed as holes, right, rather than by parts. If you put people in the scanner again and you show them pictures of illusory faces, the same regions that are specialized for faces would light up as well. That said, there are some differences as well. So I'm actually currently working with, you know, with my old master's student, Lizzie, writing a paper and where we show is that there, despite these similarities, illusory faces are not as effective as real faces in capturing our attention. So we use sort of like a visual search task where you have, you know, like. 12 images on a screen, you know, they're just pop randomly in different places. You're supposed to locate if there's a face there as soon as you can, something like that. Right. And people are really good when the face is a real face, right? They find the face faster than if the target was a butterfly or a flower or whatever else. But when you show them illusory faces, they're not as good as they are with real faces. They're still better than. compared to butterflies and flowers, right? But the advantage conferred by illusory faces is not as obvious as the advantage given by real faces. So there are some differences there, but we're still trying to clarify the picture here. Fun fact, a by-product of seeing faces in things, even illusory faces, is why... one assumes that we can see God and ghosts and stuff like that. It's a byproduct of why we are religious. Yes, yes, yes. It's closely related to how we attribute minds when they don't exist, right? Yes, because minds and faces are closely intertwined and it's really interesting. Again, there are studies looking at what features in the face make us attribute minds, right? Because you could imagine a face of a doll and then feels like, well, that's a doll. attribute minds in there, but that's a face of a real human. And where is that kind of threshold? If you kind of morph adults face to a human's face, right? At what point we start to attribute, okay, now this is, there's agency there. This is, we can assign things, we can assign blame, we can, you know, reward and praise. Um, so that's kind of, I guess, one flip side. The other flip side, as I mentioned before, is the super recognizer. So this is really interesting because in the last, you know, 20 years. people have started looking at individual differences in face recognition. We used to think that with face recognition, you either have it or you don't. But it turns out that there's a significant variability of face recognition skills in the population. So that is to say, us three here, our face recognition skills are probably not the same. You guys probably have better skills than mine, because mine is not good. But most people are kind of average. Some people are better, others are worse. And some people are... really, really bad at it. These are people with lifelong prospec nosia, and some people are really, really good at it. And these are the super recognizers. So people with super recognition, they really, you know, they really have amazing abilities with faces, you know, they see a face once and they say like, Oh, you know that I saw you in that shop, you know, by the university like three and a half years ago, and you're doing this and that and people's like, what? It can sound creepy, like, you just like, what's going on with this person? And again, it's not a it's not a general or superior memory skills. Right. So they tested people who compete in, you know, memory championships. I think there are these things where you're supposed to remember as many things and possible as many formats as available. And these people are not good when it comes to faces. So you can dissociate superior ability and face recognition from superior ability and remembering things more generally. And the supers have been put to good use, I think in London, in Berlin. I think they work with the police officers, forensic examiners. You can imagine this cuz sometimes you have to identify people from bad CCTV images and the supers are doing a good job with these stimuli. That's so cool. Um, I remember when I remember growing up, one of my mother's coworkers, um, he worked in the genetics department as well, cause my mom's a geneticist and he would see a child or any patient walk in and based on how they walked in, he could say, oh, they have this gene mutation and it's this version of this mutation and I know it's not exactly the same as just recognizing faces, but it was just this uncanny ability. of walking down the street. Yes. Uh, like you and him just seeing someone and being like, okay, they have this mutation because you can see their lip curve. Yeah. People have different, you know, kind of cognitive sensitivities to different things. I mean, we call them all geniuses, right? But geniuses come in many flavors. And going back to my, you know, I guess there was a question early on about evolution and I talk about face recognition, having, uh, you know, sort of like a set of specialized mechanisms, uh, in the, in the brain, uh, it's probably not that surprising if then, you know, some of these mechanisms, you know, approach kind of the genius threshold, right? And some people are really, really good at it, just like, you know, some people are really good with math, for example. And on the opposite side, you have dyscalculia, right, which is a, you know, the inability to work with numbers, which is quite specific again. And so I didn't mention this at the beginning, but some people, when they think about Prospect Nosia, they, they they think of it as one of the kind of selective, I guess, cognitive disorders or deficits. I mean, the others being, you know, I mentioned dyscalculia, but there's also dyslexia, which is probably the most well known, right? And then there's amusia, so people who can't perceive music, as we call them, tone deaf. But it's quite specific. Again, it's not because they have general learning disabilities or bad memory or bad auditory. system. It's not all that. It's very specific to music. There's topographic nausea. So it's a mouthful. So people who get lost all the time. So these are people who can't form kind of a mental map of the environment. So when they navigate the environment, they tend to rely on landmarks. So I see that building. When I see that building, I turn left. But they actually have no idea about where left is relative to right. If you ask them to close your eyes and imagine, okay, now you're here. Imagine going that way and that way. How do you get from the School of Psychology to the HUB or something? They'd be like, I don't know. Nothing comes up. The most recent one is probably Aphantasia. It's on the news recently. Aphantasia is the inability to imagine things visually, the inability to come up with pictures in mind. Right? And so, you know, if you close your eyes, can you bring up a picture of this? And say, no, it's blank. I think if anything visual for me has to be seen, the stimulus has to be in front of me. Yeah. If I close my eyes, I don't imagine anything. I can't, I don't even know what that question means. Kind of like, what do you mean imagine things? Like, okay, just quite wild again. That's really interesting. Cause I was talking to like some of my friends and I asked, because it's so wild to me that I always have like a running. monologue or vision of something going on in my head. And I met someone, I was like, so what do you do? Like, how do you think of things? And then that person was like, I don't, I just feel them. And I'm like, I don't understand what you mean. Yeah, yeah, I guess so much so for, for naive realism, right? I mean, this, all of these kind of, you know, attest to our different phenomenologies. I mean, we experience the world differently, right? So when you say something is green, well, that thing's not actually green, that thing just reflects certain wavelengths that are processed by our visual system and we interpret as green. And these different conditions, I can bring home that point more clearly by saying, what do you mean by visualizing things? You visualize it, I don't. Absolutely. So, yeah, so Aventasia has received a great research interest and people wanna know what it is and do you have it for non-visual modalities? Like people have inner dialogue, inner monologue? Yeah, absolutely. And some people don't have it, so like, it's all. It's all very fascinating, still many unknowns. That's so fascinating. I wanted to ask, what, because you mentioned at what point do you kind of identify consciousness, right from a doll to a human? Isn't that term called the uncanny valley? Is that what it is? Is that something? Yeah, yeah. So it's uncanny valley. I think it's been around for a while. I think it was first coined by a Japanese researcher way back when. But I think the evidence or the I guess the results so far is they're probably more mixed than people think So sometimes it's not clear where the uncanny Valley is Or what features of a face give rise to the uncanny Valley But but I suppose the uncanny Valley When it was originally coined, I think it refers more to this kind of uncanny feeling that something is something negative at some point, right? Where you transition from a non-human face to a human face, where you feel a bit maybe even grotesque, like you feel like you want to move away from the stimulus. There are other studies that have failed to replicate the uncanny valley, mainly that you can morph a doll's face to a human face and at no point in that spectrum that you experience any uncanniness whatsoever. But you still have a point where you start to, okay, That's where I would start to attribute minds, where the face comes alive, so to speak, as opposed to just it's a robot's face or a doll's face or a mannequin's face or like that. Yes. And Ken, for, I guess for the last part, because I know you have to leave, can we talk a little bit about the neurological side of it? So in the sense, what kind of activity goes on in the brain in all these things? So do you, is there different activity patterns when in prospect, noses versus, I want to say, people who are on the spectrum? Typical controls, right? Yeah. Yeah, with the acquired prosopagnosia, it's clear, because usually you have an injury to one of these face regions, right? And then, you know, so you clearly see the face, the region's no longer there. With lifelong prosopagnosia, there are subtle differences, but only when you do large group studies. You have to kind of bring in 50 people with prosopagnosia and 50 without, and you average the results. And then you can see, okay, both groups still have these dozens of areas, but the... prosopagnosics, they show weaker activations overall, or maybe the different areas in the network are under-connected. So they're not talking to each other as much as they do in the controls, for instance, right? So you can find these kind of subtle differences, but I wouldn't go as far as saying that we have found a biomarker for prosopagnosia, which I think is also true with other conditions, right? With autism and other people have been. hunting for these biomarkers for ages, but it's always very tricky. The most promising results are usually results that stay at the group level, right? So we say, okay, on average, there might be some differences, but you cannot find a robust marker that can be applied to a single brain. And you say, okay, this person must have it or this person must not. We're not there yet, I suppose. Just to build on that, I had a quick question about supers. Do they have a different... brain structure. Sorry, I'm not a neuro science person. That's the word. Neuroscientist, yes. As far as we can tell, no. So they have the same set of areas in the brain. They have a similar visual system. In some cases, there seems to be overactivations to some extent, but it's not clear. So we really can't explain why they have the ability that they do. And so, yeah, more research needs to be done. But we know that their ability is real, because I think it's been really documented. And you can give them really, really tough face recognition tests and they can crack them. And I guess it's sufficient to say that it's harder to, if you want to fake your way, it's easier to fake your way into having prosopagnosia, right? I'm just going to press random buttons and pretend I can't recognize faces. But if you want to show superior ability, you can't take your way. You kind of have to really know what you're doing. And so with the supers, I think there are some cases who are really, really solid in the sense that these people really can see things that we cannot. faces. Yeah, really cool. I like that you guys call them supers, like superheroes almost. Well, it's a super, what do you call that, almost like a superhero ability in a sense, right? Because you could do things that most mortals can't do, right? Given the same picture of faces, you can tell, oh, these two people are the same. And they are, whereas for most of us, there's no way these two... These two pictures show the same person, but they can tell. Interesting. Yeah. Did I answer your question about brains and neurons here? Or was that the... Yeah. Yeah, mostly. I guess one more thing on the same lines would be we hear often about top down and bottom up processing. So kind of getting visual information in and being able to... So from getting information into being able to perceive something based on what you know. So where do most of these issues fall in when it comes to it? Is this more a processing issue or is this more the second part of the connection? I think it's probably the same. I mean, this is an old issue, as you can imagine. So going back to before prosopachnosia, people have long known about visual echnosia, right? So this is a general problem recognizing objects. visual agnosia. So one is kind of more perceptual. I think it's called a perceptive agnosia. So people who have a perceptive agnosia, they can't even create a good perceptual representation of the stimulus in front of them. Right? So the sensory input is coming in, but it's not being processed properly. And so the evidence is that if you ask them to copy a drawing, let's say, you know, they, you know, just look at this and it's here, you just have to produce exactly the same thing next door, they can't do it. The other type of agnosia is called associative agnosia. So associative agnosia seems to be rooted in later stage processes. So after you create a good representation of what you see, you still have to connect that representation with knowledge, right? With what you know that, okay, so I'm seeing a car right there because I know what a car looks like. And so people who have associative agnosia, they would be able to copy a drawing of a car, but then they wouldn't be able to tell you that that's a car that they're copying. They just like, okay, I see the curvy bit on the left, I'm producing it here. There's a rectangle over here, which is the window, for example, and they just draw the rectangle right there, but then they say like, okay, what is that object that you just copied? I don't, no idea. I don't know. So. And I think the same distinction can be made for prosopagnosia. So some people report difficulties just even describing or creating a good image in their mind's eye about the face that is in front of them. Others probably have trouble associating the percept, associating the face that they're currently holding in their mind's eye with their prior memory and knowledge about that face, if they've seen that face before. Awesome. So can I ask what kind of projects you're currently doing? And what is your Yeah, what's your current research? Like, and what do you plan on doing in the future? Yeah, there's a couple of lines of work. So one is looking at kind of the more perceptual aspects of prosopagnosia. And this is because there's some recent data suggesting that most They, so we used to think that prospect knows it's more about associating rights, have more about recognition memory problems where they just can't remember people's faces. But I think there's some intriguing data recently suggesting that the problems might be earlier than that. The problems might be in problems associating not sorry, problem perceiving faces rather than associating faces. And so if you give them tasks like, you know, you show them two faces side by side. And you say, are these two phases the same or not? So you don't ask them to learn the phase or remember them for later testing, nothing like that. Everything is on the screen and they just have to discriminate between these stimuli. They have problems with that. So we think maybe prosopagnosia is more of a perceptual disorder than people think. So we're currently looking into that to see what perceptual aspects are. are impaired and how so and so on. Another line of research looks at potential strategies for improving face recognition in prospectus. Yeah, so some groups have worked on this for a while, but it's a tricky issue. So most studies they're on, I guess relatively small samples, which makes things quite complicated because if you wanna do these things properly, you're gonna have to have a randomized control trial, with like 50. prospect knows X 50 control and all matched in all sorts of ways. Uh, and then you have to check whether whatever strategies you've come up with, you know, the outcomes, uh, persist, you know, beyond kind of the experimental session, right? Or, you know, what will happen three months down the road and things like that. So yeah, a lot, a lot to do there. Awesome. Um, I know you need to leave. Uh, so Farrell, do you have any final questions? Um, yeah, sorry. Again, a silly one going back to it. Why would people and do people fake having facial blindness just for fun? Maybe. I mean, I don't know. Occasionally, I don't have a good feel in terms of the estimate, but occasionally there are people who, I don't know, they just say like, hey, I have this and that and they kind of, when you look at their experience and the pattern of responding, when they did the battery suggesting that it's probably... It's not prospec nosia what we're seeing here. It's something else, but it's a small minority. Most people who work with us, they're being genuinely honest. They're just saying, you know, I have trouble with basis in my life, right? So I just wanna know whether I fit the criteria. And often what happens is they're actually glad if we say, yeah, your numbers actually check out and they pass the statistical threshold because then they have kind of something. They have a name for the condition. The sad thing often is that if you don't know that you have this, then you often can blame yourself and say, you know, I'm just not attentive. I'm not socially good. Maybe I just am not a kind person or something. But actually, no, it's nothing like that. It's just your visual system is a bit unusual. There are some alterations there, but it has nothing to do with you and your motivations and your values. So people are often, I wouldn't say happy, but... Reliefed, it's probably the word that, hey, oh, that's good. And then they ask you what strategies are out there for, you know, I can use, is there any cure? The answer is no, not yet. We have no cure, but we have some strategies, you know, focus on non-facial cues and being upfront, I guess with people is probably the best, you know, just be honest and say this. And it also helps raise awareness about the condition. Right. And also other conditions. Then if you read about aphantasia or dyscalculia and whatever, it's just, you know, every brains are different. Right. So I think that's probably the take home message for all of us here. And you're a scientist like brains, every brain's different. Uh, the basic structure is probably the same, the blueprint is there, but you know, there's so much variation and it's all part of the same role. Yeah. Awesome. Thank you so much. Yeah. You made that, you made that very nice. And was that the closing? Cause I w because I was going to, cause I was going to go with. saying like, I can answer the question why people might fake it. Example, you're in town and you don't want to talk to them. But you just made it really nice. So, all right. So what we usually do is we ask a bunch of rapid fire questions, but because you have to leave in two minutes, I will ask the three or four ones, which I think would be really nice for someone who does visual perception. and things. I also have to ask a couple of the basic ones. So first of all, cats or dogs? Dogs. If your life were a movie, what genre would it be? Action. Nice. What superpower would you like to have? Time travel. I'm surprised you should have gone with being able to read faces really well. No, I've studied it enough and I don't care. Time travel. I'd like to time travel. Um, if, if you were an animal, what animal would you like to be? A bird. I guess we're travel again, isn't it? A little bit. Yeah. Um, if they're okay, uh, the last couple, so do you have a version of there are two kinds of people in this world? Not really. There's more than two. I think that oversimplifies things. All right. Uh, the final question, which we ask everyone is if you had to leave. All our listeners, everyone with one piece of advice, what would it be? Uh, keep listening to smooth pain. Oh, yes. Is that good? That's fantastic. Oh, we obviously need to have you back on to talk about all the things you did you've done and what you spoke about now in more detail, but happy to do so. Time constraints. So yeah, thank you so much, Tilda, for coming on. Thanks for again, for jumping in. Yeah, thanks for having me. And, and thanks everyone for listening. All right. Until next time, take care.