When your “mind’s eye” is blank: Understanding aphantasia, with Joel Pearson, PhD

Try to picture an apple. For most people, that's easy. The word conjures up an image in their mind's eye of a round red fruit with a brown stem, maybe a green leaf on the top. But for people with aphantasia, it's impossible. Trying to picture an apple or anything else brings up nothing but essentially a blank screen. Today we're going to talk with one of the world's leading experts on aphantasia or the inability to visualize things in one's mind's eye. about what scientists are learning about this recently identified condition. What causes aphantasia? How common is it? How do you reliably measure a person's inner experience, like the ability to form mental images? What effects might aphantasia have on people's lives, from memory to creativity to mental health? And what can studying aphantasia tell us more broadly about how the human mind works. Welcome to Speaking of Psychology, the flagship podcast of the American Psychological Association that examines the links between psychological science and everyday life. I'm Kim Mills. My guest today is Dr. Joel Pearson, a professor in the School of Psychology and director of the Future Minds Lab at the University of New South Wales in Australia. He is a cognitive neuroscientist whose research explores intuition, the human imagination, aphantasia, and the psychological impact of artificial intelligence. He's a sought-after speaker, author, and writer who has published dozens of peer-reviewed research articles and whose work has been covered by media outlets including The New Yorker, ABC Australia, and The New York Times. Dr. Pearson, thank you for joining me today. My pleasure, Kim. Great to be here. I described aphantasia in the introduction a moment ago, but let's start with a little more context and history for our listeners. So can you tell us more about what exactly aphantasia is and how long have scientists recognized it as a distinct condition? Absolutely. Yeah. So it's generally considered the inability to visualize. So sometimes people will use the phrase imagination, but that's a very broad phrase that people get confused with creativity and other things. So it's really the inability to visualize typically visual mental imagery. And we'll unpack some of the other senses a little bit later. So mainly it's talked about or referred to as the inability to visualize. So when you think about, like you said in the introduction, what an apple might look like for someone like me who has mental imagery, I have this sort of momentary glimpse of a conscious experience of the colors and shapes of the apple. and I see it and then it fades and it comes back. So people who don't have any mental imagery won't have that. They will have a black on black experience. There are all kinds of different descriptions. We hear about it like a black velvet with a black background. So there's almost something there, but not quite. So that's sort of typically refers to the voluntary. I should also mention that a voluntary creation of the mental image. So we can also dive into voluntary involuntary. And interestingly, we've known about sort of the existence of aphantasia for quite a long time. So Francis Galton published his paper in about 1883, which has become very famous since then, where he had his friends and colleagues come in and sort of describe what they had for breakfast, what was on the breakfast table. And he discovered that some people could not recall or not recreate that mental image. And so he concluded that some part of the population has no ability to visualize. Then over the many, many decades since then, there's a few papers which touched on this idea of having no mental imagery, but it really wasn't until 2015 where a paper gave it the name Aphantasia, coined this new name for it. And then there was a few media articles about it. And then the idea kind of just took off in the sort of people's minds and I almost said imagination. Yeah. It's sort of just people started identifying with it and thinking about it and it's just, it's spread. And so everywhere I go now and speak, you know, people know about it or people are discovering about it. People are really fascinated about these individual differences in the way, the format of our thoughts, things like this, how, you know, some people can think in pictures, other people can't, what does that mean? how their brain's different? What does it mean to their everyday life, their creativity, their relationships, their jobs? All these questions have been popping up. So it's, you know, in the last sort of decade or so, the topic has just gotten so much attention and so much, yeah, scientific and general public attention. Well, let me ask you how common is aphantasia? I mean, for those of us who don't have it, it's very hard to imagine not having a image. You try to stop yourself. If I say, don't think about an elephant, you're going to think about an elephant and you'll see it. One thing I'll say up front is that the main way to measure mental imagery or aphantasia at scale is using a questionnaire, and that's called the vividness of visual imagery questionnaire. And using that technique, we think it's sort of four or five percent of the population. One of the downsides, I'm a huge fan of questionnaires, but one of the downsides is that the questionnaire like this is really examining two things at once. It's examining someone's actual visual mental imagery, but it's also examining how they decide or their criteria for giving a number to that mental imagery. So you and me, Kim, could have the exact same mental imagery of a sunset and you could decide to give it a two and I could decide to give it a four or five. And that's our internal criteria or metacognition of our assessment of that. What we're also finding is that some people who have aphantasia have lived their lives thinking that the idea of mental imagery and visualization was a metaphor. And so they assumed that everyone had the same experience. And so when they fill out a questionnaire, they tend to score it quite highly because they don't realize what mental imagery can be in others. And so we found quite a few of these people that when you then just talk about or give them a little video about what imagery can be, that it can be this conscious visual experience, they're genuinely shocked and they all often readjust their numbers in the questionnaire they reported downwards. So for those reasons, I suspect that the estimate might be a bit higher than the 5%, maybe in the 6%, 7%, 8% range, but we haven't been able to use our more objective lab-based techniques to assess visual imagery on a large scale study yet. Now you've come up with a different technique, right? I mean, it's not just self-reports on a questionnaire. You have another method of measuring aphantasia. Can you talk about that? Yeah, we've actually developed three different methods over the years. And the first one that was pivotal in my personal journey getting to study mental imagery was using a visual illusion called binocular rivalry, which as it sounds is rivalry between the images going into each eye. So if I put up a hand in front of one eye, my brain, my one eye, my right eye will see my hand, the other eye will see you on the computer screen. And that puts my visual system into this state of conflict, hence rivalry. And when you sort of balance those images out, you get these beautiful vacillations and oscillations of consciousness between whatever's going to one eye versus the other. And so we use that visual illusion, binocular ivory, to study consciousness in its own right. But I discovered many years ago that you could actually use the illusion as a way to measure mental imagery. So how it works is, let's say we have a binocular ivory stimulus set up. So we have a red pattern and a green pattern, one going to each eye. We just get participants to try and imagine one of those patterns. So they imagine, say, the red pattern. Then we just briefly flash on this binocular ivory illusion and we found that what they imagined tended to be what they see. In other words, the content of their mental imagery, their visual imagery, was biasing the way they saw this visual illusion. You imagine red, you see red. You imagine green, you see green. And over a number of trials, that turned out to be a nice way to measure the sort of sensory strength of visual imagery. So that was the first method. And we've sort of developed two other methods. Another way to do it is using emotional mental imagery. So we have people come into the lab and they wear a little thing on their finger, which measures skin conductance. So just sort of the levels of micro sweat on the skin. And then we have them read out these kind of scary scenarios. They're swimming in the ocean and a dark shadow moves underneath them. Something bumps their foot. They look back at the beach and people are screaming, you know, and the shark gets closer and closer or they're rock climbing and their fingers start slipping. and we find that this skin conductance response, which is kind of a way to measure stress or anxiety, if you have mental imagery, goes up as they're reading these stories. If people are doing the experiment who have a fantasia you see more or less a noisy flat line So there a difference in that sort of emotional or stress response If you show both those groups just scary images, pictures on the screen, you see more or less the same response. So it does seem to be just the role of imagery in translating the words into ideas, into a visual imagery that drives more emotion. And we'll see a bit later that this emotional response is one of the sort of big thematic differences between thinking in pictures or not thinking in pictures. And just very quickly, the third way is using your pupil. So people will know that if you look at a bright light, if you look at the sun, which you shouldn't, your pupil will constrict, right, to protect the neurons in your eye, let less light in. It turns out that if you imagine bright things or dark things, your pupil also responds. So you get people into a dark room and you say, imagine you can just use simple shapes or you can use, you know, real objects. Imagine this under bright lights, a bright square or a dark square. And you'll see that people will also constrict when they're imagining the bright square. So you can measure this with a little infrared camera quite easily. And it turns out that's also a nice way to measure mental imagery. If you don't have mental imagery and you try and do that task, your pupil doesn't respond. Interestingly though, there's a nice control in that experiment that you can get people to try and imagine one object, two objects, three objects, or four objects, and the sort of mental load is more with more objects. And we see that the pupil also responds to this mental load. And we see that response in both groups, those with visual imagery and those with aphantasia. So that's a nice way to control because many people would say, oh, how do you know that people with aphantasia just aren't trying? And so this sort of set size effect of the number of objects is a nice way to provide evidence that yes, people with aphantasia are indeed trying. We can see this difference. So that's really the three ways of measuring imagery. Of course, you can use brain scanning, fMRI to look at the visual response in visual areas, but that's much slower and much more expensive. But speaking of brains and fMRIs, what do we know about what's happening in the brains of people who have aphantasia? Do we have information from these brain studies? Yeah, we have. We've done brain stimulation studies and functional magnetic resonance imaging studies. We've done sort of anatomical studies as well. So first up, we have evidence that the size of visual cortex, so if everyone remembers the cerebral cortex around the outside is this big sheet, but it's all sort of scrunched up to fit inside the skull. Now you can measure that in a brain scanner, and then you can kind of flatten it out and measure the size of different brain areas. And we've done that with visual cortex, the part of the back of the brain. And we find that those with a smaller visual cortex tend to have stronger mental imagery, which is interesting in itself. And there's also evidence that there are genes which contribute to the size of visual cortex. So there's also emerging evidence that there might be some genetic components to aphantasia. We've also done research looking at the cortical excitability of visual cortex. So a nice way to think about that is there's all the neurons in your visual cortex or neurons are never just quiet and doing nothing. They're always sort of what seems like random firing. There's this baseline activity. And we find that that baseline activity is also related to visual imagery strength. So the noisier those visual neurons are, the weaker the imagery tends to be and the quieter they are, the stronger and clearer mental imagery seems to be. Now we can measure that with TMS, transcranial magnetic stimulation. But we've also done a sort of causative manipulation of that by using a type of brain stimulation, which runs off a small battery, TDCS, a transcranial direct current stimulation. And when we do that, we can up or down regulate that sort of resting state cortical excitability. And we see that when we do that, that imagery can be, we can make it stronger or weaker. These are not massive effects, they're quite small effects, but they are reliable. And we're measuring these effects using that binocular ivory method I mentioned earlier. Then more recently, there's been a bunch of research we've done looking at trying to decode mental images in visual cortex. So we've known for a while that if you have mental imagery, when you imagine something, just like when you look at something, you can decode that pattern of activity and know what someone's looking at using sort of more modern fMRI techniques, algorithms, and a bit of AI sometimes. Now, it turns out, interestingly, you can also do that in people with aphantasia, which is kind of strange because they're saying they don't have any imagery. They're trying. There's no conscious experience of imagery, but it seems like there's a decodable pattern in their visual cortex. So then the question then becomes, what is that pattern? why is it not conscious and that has started sort of these debates around this idea of unconscious imagery and maybe there could be two different types of visual aphantasia some sort of what people might call like a true aphantasia with zero imagery and another type where there is sort of some residual representation and for unknown reasons at this stage that representation remains unconscious, maybe people can't pay attention to it, or for some other reason, the format is slightly different and it just remains unconscious. So that's where things are at the moment and people are sort of getting excited about how to then sort of probe this idea further of unconscious imagery. There does seem to be other evidence we've collected from non-Aphantasia research that if you do have visual imagery, you can have unconscious imagery, just like you can have unconscious visual perception, kind of a tangent, but it does seem to be there. So it could be that there is something similar happening with aphantasia. Do people with aphantasia dream? It turns out, yeah. All we have at this stage is questionnaire data. We haven't done the study that we'd love to do, which is a proper sleep study where we get people in the lab and they have a sleep lab where they sleep all night and we wake them up and monitor their brain activity. but looking at the questionnaire data, it seems that some do, some don't. So when you average all the data, you do see significant differences in the amount of dreaming, the sensory qualities of the dream. But to really understand the data, you're going to kind of dig more on an individual level where some people report they have no memory of dreams. Some people report still dreams with emotional content, but less visual. Some people report sort of black and white dreams. And so there's kind of a mixture state there. But there are certainly people that have aphantasia and do report dreaming. What about reading? I mean, if you're going to read fiction, you are going to have a mental image of what's going on in the story. I mean, do people with aphantasia find reading fiction in particular so boring that they just can't do it? Well, not so boring that I never read a book, but there is emerging evidence, and I think some papers are about to come out on this where, yeah, if you think about that study I mentioned before where you're reading emotional content, the skin conductance response was different. So you can think about that to reading an exciting or scary novel. Without those pictures in your mind, the experience is going to be, I don't like to use the word, lacking, but at least in terms of emotional content, it probably will be lacking. I don't want to make claims in other areas. And so because of that, yeah, there is some evidence now that people with aphantasia enjoy reading a little bit less when it comes to fiction or get a little bit less drawn into the stories. And that's sort of that theme I mentioned earlier, that this idea of imagery as this virtual reality simulator that can amplify emotions. And so there's sort of this interesting link between thoughts and the emotional responses, the emotional parts of our brain. And imagery seems to sit there in the middle. And it's almost like if you have imagery, it can kind of trick the emotional parts in your brain to thinking the content of imagery is actually happening. And so it responds more. So I mentioned that skin conductance response. We have done studies looking at risk perception, looking at empathy, looking at mind wandering. And we've done studies looking at models of PTSD. So PTSD, lab-based models of PTSD where people come into the lab and watch a real sort of pretty unpleasant video. And then we send them home with an app that sort of they monitor every time they think about that video or have an image pop into their head or have any thoughts pop into their head And we see stark differences there between those that have imagery and aphantasia And when they do think about that video the emotional response and how disruptive it is to their life is very different So across all those examples sort of the empathy, the mind wandering, some moral dilemma stuff we're doing now, it seems that this emotional response to thoughts, thought simulations is just different with or without imagery. So sort of from anxiety through to basically anything that you think would benefit or be different with a sort of virtual simulation of the thing, a sensory simulation does seem to be different. And that would include, you know, addiction and cravings, you know, a lot of things there. So that is probably the biggest difference we see in thinking with images or thinking without images. I am wondering if there's a relationship between aphantasia and prosopagnosia or face blindness. If you don't have a mental image of the things you have experienced, does that affect whether you can recognize people or places you've seen before? There are studies, we've done studies on episodic memory, so lifelong memories. And we find that using these sort of interview style techniques, we've got to remember events that happened, you know, a month ago, six months ago, years, 10 years ago, that those with aphantasia recall less details about very similar events compared to those with imagery. Of course, the vividness, the emotionality of those experiences are also different. But the details thing is kind of quite interesting. And it's not devastatingly different. It's not like there's no details. There's still plenty of details. But it is significantly different or significantly more details if you have imagery. So the memory of experiences in our lives does seem to be different if you have an image attached to that memory or can recreate that image. I think there's some evidence potentially linking prosopagnosia. I don't know how strong that evidence is. I have certainly come across individuals, not many, just like two or three, who claim to have sort of a very specific version of aphantasia, which is face-specific and human face-specific. So it's kind of like a prosopagnosia version of aphantasia. They say they can imagine, their dog's face, fine, but they can't imagine human faces. They can still recognize them, but they just can't imagine them. So it's not just prosopagnosia. It's like an imagery version of prosopagnosia. Again, only a handful of cases I've seen of that. But yeah, there certainly does seem to be these differences with memory and the amount of information you can recall. We're going to take a short break. When we return, I'll talk with Dr. Pearson about what it's like to have hyperphantasia or extremely vivid, detailed mental imagery. Let's talk about the other side of the coin, which is the people who have constant images or a hyperphantasia where it's extremely vivid and detailed in their minds all the time. I mean, how common is that? And do we all just sort of fall somewhere in between one or the other? Yeah. So there does seem to be almost a normal distribution or at least something that's shaped like that. Whereas there's this sort of bell curve where most people fall in the middle somewhere, and then you have these tails that get thin on the end. There's been much less research done on what's called hyperphantasia, or if you go back a few decades, it was called eidatic imagery. So there was a whole field of research into what was called eidatic imagery in children back sort of last century, looking at this idea that children under 11, under 10 years old had much stronger imagery than something would happen during their teenage years and the imagery would get weaker. Again, some of that research is a bit dated now. We don't have the same techniques for measuring these things. They didn't have those techniques back then, so we don't know a lot about that using modern techniques. Because aphantasia gets a lot of media attention, we have huge databases with many thousands of people that have aphantasia, but in comparison, and we have a very small database of those that have hyperphantasia. And again, it's clearer and easier to define aphantasia as the complete absence. You know, you have imagery or you don't have imagery. There's kind of a step function there. Whereas it's harder to define the upper end of this hyperphantasia. When does strong imagery become hyper or not? It can be a bit of an arbitrary cutoff. And I think as we do more research into this, we will end up defining it more to do with things like false memories. So I know some people with very strong imagery who will literally have confusions about whether they imagined a scenario or whether it actually happened. There's a reason that most of us will forget our dreams so we don't have reality confusion with our dreams. But if you have very strong imagery and then you remember that, not only could it sort of affect your sort of eyewitness memory of an event, you can sort of imagine something and then that gets reconsolidated back into the original memory, you can also just have confusion between whether something actually happened at all and the visual image. So we've done research into individuals with Parkinson's disease who have visual hallucinations and we find that those with visual hallucinations have very strong imagery as measured using the an octro-ivory technique. We also see people who have schizophrenia have not only the auditory stuff, but they have very strong visual imagery. And also we see this trend in schizotypy sort of individuals as well. So on the spectrum towards schizophrenia, we see that this association between strong imagery and anxiety and PTSD as well. So there's this kind of theme emerging there that some psychological and neurological disorders are associated with stronger mental imagery. And so you could make the case that everything else being equal, if you had to choose between very, very strong imagery and very, very weak or zero imagery, you may actually want to choose aphantasia just because of this association with psychological and neurological disorders. but we know less about that the high-end hyperphantasia than the aphantasia at this stage so we don't know a lot but i've certainly met individuals who say they can they can sort of replay a whole film and they swear to me their conscious experience is like watching it on an ipad it's that clear no i absolutely can't do that so it's it is hard for me to believe that but they i've only met one or two people that say that and we haven't had a chance to study them in detail yet, but there are seemingly individuals who can do that. So yeah, that's a big difference from no imagery at all. Does aphantasia exist only for visual images? I guess my question is, is it possible to have the equivalent of aphantasia for other senses, say being unable to hear music in your mind or recall a smell or a texture? Yeah, great question, Kim. Yeah, absolutely. So it does, it's not just visual you can have full multi-sensory aphantasia so we've done some some research where we you know measured a few thousand people and ran a sort of clustering analysis or a bunch of different clustering analysis to see the the groupings and we found that yeah most people who had aphantasia tended to have this full multi-sensory aphantasia but there was also a significant group that just had pure visual. And then we found all the other groupings you could imagine, but in very small quantities or proportions. So you could have a pure auditory aphantasia, you could have auditory and visual, but they were very small groups compared to the sort of larger groups of pure visual or pure multi-sensory across all the senses. And so there is a bias there in that the databases and the people we test have heard about aphantasia as a visual thing. So of course, there's going to be more people in the database that have visual aphantasia, but the clusterings do exist there. And you can also drill down and there's people that have sort of auditory aphantasia. And then there's also a subgroup, which might be able to imagine music and sounds, but don't have an sort of inner mind's voice, if you like. When they read, they don't hear the mental version of words being read to them. They can't talk to themselves. And that's actually starting to grow into its own sort of subfield now of sort of the inner workings of the mind and the inner voice. But absolutely, imagery can be across any of the senses, which is pretty interesting in itself. And I often have thought about this, we've written about this a bit, that you don't really have a version of multi-sensory blindness, for example. I can't think of an individual in history that has had no sensory abilities across all their senses. No sight, no sound, no touch, no taste, no smell. I don't think we've ever had that, but the fact that you can have that in aphantasia already tells you something interesting about the differences between mental imagery across the senses and sensory perception, that there is something more central going on there that you can have all these things not existing together Let me switch topics here a little bit I know you studied the connection between aphantasia and creativity What have you found? What is the relationship? Yeah, so we've done a bunch of research on this. We haven't yet published them. It's kind of a bit of a pipeline in the lab, sort of a clogged up pipeline of publications at present. But in some, we found that there was no clear differences between those that have aphantasia and those that have imagery. in the sort of the classic ways of trying to measure creativity. And this is this divergent thinking tasks like, you know, here's a brick. How many different ways can you, could you use the brick? And then you have independent people score that on, you know, how creative it is and also how many different uses and things like that. So despite what people think and say that a Fantasia is holding back their creativity at work or something, the data doesn't really support that because we didn't see any differences and then having said that you know we've had aphantasia visual art exhibitions ed catmull who co-founded pixar and ran that then ran disney studios for many years a friend of mine he has aphantasia so he was crucial early on and coming up with some of the ideas and methods for doing computer design and using these sort of geometric shapes to define a square or a sphere. And he said that if he could visualize the shapes, he probably wouldn't have come up with this mathematical geometry, these little triangles and things to describe these shapes. And so he almost credits Aphantasia in helping him with some of these breakthroughs in these sort of 3D designs. Also one of their top animators, I'm blanking on the gentleman's name, but he was one of the top, the person who a lot of the little mermaid designs for the characters, he has aphantasia. And so I don't want anyone to think that, you know, if you have aphantasia, it's some barrier to being creative or starting an enterprise or a business or any of these things. It does not seem to be the case. So I think it's important to get that out there. Yeah. And I didn't want to give the impression either that aphantasia is some kind of a disorder that needs to be fixed. I mean, it seems from what I've been reading anyway, and you would know better than I, that people who have it don't feel that they're in any way held back in life. But I'm wondering if there are interventions. So if somebody said, yeah, I'd like to know what it's like to have a visual internal life. Is there anything that can be done to help with that? Like I said, I mentioned earlier, we've done the study using that sort of that type of brain stimulation where we have up or down regulated imagery strength. All those participants had some form of imagery to begin with. Now, separately, we've done a five-day experiment where we had people come into the lab and practice their imagery every day for one hour for five days in a row. And while they were practicing, we were measuring it using that binocular ivory technique, and we didn't really see any improvement over that time. Now, that doesn't mean it's not trainable. The thing with brain stimulation is it's not magically going to tell you how to create a mental image. In the same way that if you wanted to learn a new language, let's say you can't speak Chinese and you want to learn Chinese, while I can stimulate the language areas of your brain and that would improve your performance somewhat, it's not going to magically give you the ability and the knowledge to speak Chinese. So I think the answer may be in combining practice with brain stimulation. Now, there is an emerging trend that has not, to my knowledge, been studied scientifically yet of this image streaming technique that came from photography, where people would first have their eyes open and look at a room and then verbally out loud describe the visual details as much as possible. And they do this over and over. And this came from photography where they were trying to design the right way to set up a photograph. And then the idea is then you close your eyes and try and do it by memory. And it's important, apparently that you do this out loud. So there's a few groups online, in particular on YouTube now, who are talking about that as a way to train mental imagery or give people mental imagery experience. Now, I know some people who have tried that and they haven't really noticed much difference. Some people claim that they have. And so again, it may be the case that some people who have aphantasia have some residual imagery and that can be trained up. And part of that equation might be simply teaching people what to pay attention to because they don't even know what imagery is in the first place. I should also mention there's two published case studies, they're retrospective studies from people who have been part of psychedelic research. At least two of those individuals, and by retrospective, they weren't set out beforehand to study mental imagery, they kind of discovered this along the way. And so it does rely on their memory of what the imagery was like before they took part in the psychedelic research. And they say that not only did they have the experience of imagery during the effect of the molecule, but that lasted afterwards as well. And that has given them imagery. Now, because it's just these two case studies, we have no idea whether these are two out of a thousand people, or would this work for everyone? I certainly have talked to people who have taken part in psychedelic research and have aphantasia and it didn't change their imagery. So I don't think it's going to work for everyone. But there's some interesting things possibly emerging there because we know that psychedelics will do a few things. But one of the things it does is put your brain to this very plastic state where it can rewire quite quickly. And so that's very interesting in respect to aphantasia and mental imagery. So just to wrap up, what might studying aphantasia and hyperphantasia tell us more broadly about how the human mind works? I think first up, it's a really powerful and nice example of cognitive and neural diversity across the human experience. Another way to phrase all this would be that the format, right? The format of your thoughts does change your life and it changes the way you think. It changes how much you might donate to a charity. It changes your risk perception. So anytime your thoughts will take on the format of a depictive picture in your brain and mind, then that will nudge you and change the way you think, almost like a cognitive bias or a nudge in that language. So that in itself is really interesting. I think also it teaches us about the internal types of consciousness research. I've also always been fascinated by consciousness studies. I think imagery is one of the ways to study internal consciousness. In visual neuroscience, one of the things that's really hard to study is feedback signals. So we know that there's more signals that go backwards, if you like, in the brain than forwards. So forwards means from my retina in my eye, back to visual cortex and up to the higher levels of the brain. But there's more connections that go backwards in many parts of the brain. And we don't know a lot about what those do. And it's very hard to study, but voluntary visual imagery is one of the few cases where you can have the eyes closed, have no visual stimulation, have someone imagine something and then study those feedback signals that are involved in visualizing mental imagery in a very pure isolated format. By that very definition, we stand to learn a lot about sensory perception from studying mental imagery. And if I want to be controversial and probably annoy my colleagues in the vision science community, I would say the key to understanding vision would actually be one of the keys to understanding vision would be visual imagery. And so, yeah, the neurodiversity, the understanding feedback, understanding consciousness, all those things, I think, end up being really important contributions to science in general, to psychology and neuroscience. Well, Dr. Pearson, I want to thank you for joining me. This has been really interesting. I think you're working in a very unusual part of psychology. So thanks so much for sharing your knowledge. Oh, my pleasure, Kim. Great to talk today. You can find previous episodes of Speaking of Psychology on our website at speakingofpsychology.org or on Apple, Spotify, YouTube, or wherever you get your podcasts. And if you like what you've heard, please subscribe and leave a review. If you have comments or ideas for future episodes, you can email us at speakingofpsychology at APA.org. Speaking of Psychology is produced by Lee Weinerman. Thank you for listening. The American Psychological Association. I'm Kim Mills. Thank you. you