Is Reality a Controlled Hallucination? - with Anil Seth

[Music] thank you everyone thank you martin thank you for coming nice to be back in a really full lecture theater after the last 18 months or so now this morning you all did something which was sort of fundamental to the nature of the human condition you made a transition from being unconscious into being conscious and we do this every single day when we wake up and yet we don't really know what that means we don't really understand what the transition from unconsciousness to consciousness actually how that actually transpires consciousness is of course one of the sort of central ideas that has been driving at least western thought for the last several thousand years uh mostly the preserve of philosophers and artists um and as ever and all these sorts of subjects scientists don't like to be left out and so in the last few years scientists have really had a crack at this now what that means is that in subjects particularly where you could describe them as being um opinion rich and data poor there's been a lot of very bad work on consciousness in the scientific and philosophical domains in the last few years i'm just going to quote from the speaker tonight this was said by a leading psychologist from cambridge when he uh went to become an undergraduate there in 1989 he said consciousness is a fascinating but elusive phenomenon it is impossible to specify what it is what it does or why it evolved nothing worth reading has been written on it thank you for coming no that's a joke um uh professor anil seth he's a professor of cognitive and computational neuroscience at the university of of sussex has written this fantastic book called being you which i think is destined to really be a classic and it really is one of the clearest thinkers fusing philosophy and neuroscience and computational models to try and really get at what has been described as the hard problem of consciousness what it is to be us but i think is better described by his own coinage which is the real problem of consciousness as ever with these talks and i was going to talk for around about an hour and then we're going to have half an hour of questions from you the audience we don't have uh roving mics so you're gonna have to put your hand up and shout and i'll repeat the questions and we've got something like a thousand people watching at home so i'll be monitoring the chat please keep it polite and asking um questions from from the internet as well that's it from me all that remains is for me to introduce tonight speaker professor annel seth [Applause] thank you adam and sir thank you thank you very much wow there's real people real people amazing so i don't know much about being you but being me feels really strange right now i haven't been to a lecture let alone deliver a lecture for more than 18 months and here we are here i am in this beautiful storied building with wonderful people at the launch of my own book and it feels very disconcerting but but it also does feel quite good am i the same person that i was two years ago i mean how could i be i've spent the last 18 months at home pretty much on my own this isn't my house by the way but that's been a radical disruption of the flow of events and social interactions that normally defines my life it seems to me that i am the same person there seems to be this strong continuity between myself then and myself now and that continuity in the sense of self that's a large part of what being anyone being me being you is all about now there's a well-known phenomenon in the science of perception called change blindness and while i've been talking the image behind you in the background has slowly been changing how many of you noticed the change i'm hoping some of you did i'm hoping the people from my lab noticed the change did they i can't tell i can't see them they're here not so many of you but a lot of things have changed in that image this is from a colleague of mine michael cohen in the us this is how it started and this is how it ended up i still don't know how many things change in that image it's this is a classic demonstration it's it's um lots of things change how it started how it's going how it started how it's going uh your perception changed but you did not perceive the change that's what change blindness reveals it reveals that change is not just something that happens to perception change is part of perception we perceive change in the same sort of way that we perceive color shape smell other things in the world around us now i think the same thing applies to the experience of being a self of being any self in fact it applies even more so and i call this self change blindness in the book our brains and our minds are geared by evolutionary design to perceive ourselves as changing less than we actually do because we perceive ourselves in order to control ourselves in order to stay alive the experience of being me or being you is a kind of controlled hallucination designed to keep the body going designed to keep us alive the sort of key message in the book and in this talk is that we perceive the world around us and ourselves within it with through and because of our living bodies this is the center of what in the book i call this idea theory proposal the beast machine ascent that we have conscious minds and sentient cells because of and not in spite of our nature as living machines so the challenge on the table the challenge that motivated this idea and the challenge about which nothing worth reading has been yet written maybe is that of understanding consciousness of understanding this relationship between a physical material system such as a brain and a body and the private intrinsically subjective and big and beautiful world of subjective experience and of being a self within it how does that happen well as always it's best to start with a definition and my favorite working definition of consciousness comes from the philosopher thomas nagle who said that an organism has conscious mental states if and only if there is something it is like to be that organism there's something that's like for that organism to exist there's something it's like to be me there's something it's like to be you there's probably something it's like to be an elephant or a a bat or a or a kangaroo but there's probably nothing it's like to be a table a chair a laptop computer or a glass of water there's nothing going on for those systems that's all consciousness experience is it's also important to say what it is not consciousness is not the same thing as just sensitivity to the environment this venus fly trap is going about its business without anything going on for it there's no need to assume there's consciousness happening for this plant it's not the same thing as intelligence when alphago beat lee sidol back in 2016 there was no need to be aware of what it was doing it's a very complicated machine learning program doesn't have to be conscious it's not the same as agency these people at boston dynamics keep building these incredibly scary robots that give the impression of executing very complex goal-directed behavior but again there's no inner light there's nothing in the universe for one of these systems a little bit more contentiously when we think about human consciousness certainly i don't think that consciousness is the same as having the fully reflective self you know the self that means that you know that you are conscious you know your name and so on that's something that's a bit extra conscious experience is just the presence of any experience at all in fact you can think of it as the space in which all experiences appear and then comes the question again how does that happen how does consciousness relate to this mess of electrochemical wet wear inside our skulls faced with this problem it seems almost difficult that it could be solved by science at all and in fact the philosopher david chalmers has put it very strongly with his famous or now infamous heart problem of consciousness he puts it like this he says that it is widely agreed that experience arises from a physical basis but we have no good explanation of why and how it so arises why should physical processing give rise to a rich inner life at all it seems objectively unreasonable that it should and yet it does the intuition driving this is that even if you solved what charm has caused the easy problems and these are the problems basically how does the brain work as a mechanism how do all its complex circuits take input and deliver output guide our behavior implement memory all these things even if we solve all of those the hard problem of why there's anything going on in consciousness would remain pristine and untouched it would get us nowhere that's the intuition now faced with a hard problem some people some thinkers have lurched to apparently quite radical uh approaches or potential solutions we have pan psychism consciousness is fundamental and ubiquitous it's spread out in the universe like a thin layer of jam this is pancake and this is like the problem with pan psychism is not that it seems crazy the problem is that it explains nothing it can't be tested and it doesn't lead to testable predictions i don't like it very much as you can tell at the other extreme there are certain views that say oh no actually we're so we're completely mistaken about this sense of mystery when it comes to consciousness there's nothing really mysterious at all it's just mechanism that's all there is consciousness doesn't really exist at least not how we normally think of it now i think of this position it's a bit like a medicine if you take the right amount of it it's very useful because it opens up a little gap between how things seem to you and how you might understand things actually are but if you take too much of it and think that no consciousness doesn't exist well that's a place i don't want to go because consciousness i think for me for most of us is actually all there is without consciousness there's nothing at all so my approach and it's not only mine i just sort of call it this way it's the approach of i think most people working in this area is called the real problem of consciousness you take the bull by the horns consciousness exists recognize its intimate dependence on the brain and the body and try to figure out what's going on and the particular way that i like to try to do this is to try and ask how mechanisms and processes in the brain and body explain predict and control properties of consciousness and these can be both functional like what can we do because we're conscious when i'm conscious i can do various things i can i can have a you know see this glass of water i can drink from it i can ignore it i can throw it over my shoulder there are things i can do in virtue of being conscious but there's also a phenomenology to it there's something it is like to have a visual experience that's different from what it's like to have an emotional experience or a smell to experience a smell if you explain predict these properties then you're getting somewhere in a science of consciousness this is neither the hard problem because it's not trying to to answer the question of how you magic experience out of mere mechanism and it's not the easy problem either because you're not just explaining the brain as a machine any sweeping conscious experience away under the carpet it has many answers there's many other similar traditions i just want to not pretend that it's completely new not at all i'm very influenced by this thing called neurophenomenology associated with the chilean neuroscientist francisco varela who died 20 years ago similar idea and the underlying intuition is that this way instead of solving chalmers heart problem we dissolve it and there's historical analogy for this which i find a little bit useful which is sort of fading into view now not that long ago scientists biologists chemists were perplexed about how science could explain life life seemed to be something beyond what could be explained in terms of mechanisms this of course led to vitalism this idea that we needed an ellen vital a spark of life now we don't think of it this way at all there's no need for that hypothesis of a special source and my hope and belief actually is that the same thing will apply to consciousness instead of treating it as one big scary mystery in need of one handing a eureka moment of a solution by examining its properties separating them out looking at them explaining them in turn we will dissolve the hard problem of consciousness just as a hard problem of life was dissolved in the past now life is not the same thing as consciousness this is this is certainly very true i think one of the most important differences between life and consciousness is you you can't really put a conscious experience on the table and look at it conscious experiences are intrinsically subjective they exist for the organism having them this is a problem that makes consciousness hard to study how do you get the right kind of data but it doesn't make a science of consciousness impossible as some people sometimes claim it just means it's quite challenging you can still get data about what people's experiences are like and you can try predict explain control so just as in the study of life people identified different properties that living systems have things like reproduction homeostasis metabolism we can do the same thing with consciousness it's not just one big thing we can think of it in several different ways and the ways that in the book and in my work with my lab in sussex focus on different aspects there's conscious level how conscious are you when you're conscious broadly the difference between being under anesthesia and being awake and aware as you are now then there's conscious content when you're conscious you're conscious of something right now your conscious is my voice and of this slightly strange experience of being surrounded by lots of people but there are colors shapes sounds feeling of your body against the chair those are the contents of your experience and especially the last one is related to a very important for many of us and certainly for me the most essential aspect of conscious content which is the experience of being a self the experience of being you so let's start i'm going to rattle through a few things about each of these domains of consciousness and we'll start with conscious level what in the brain explains the difference between being awake and aware and just being a chunk of living meat without anything going on for you the first thing to say about this is that conscious level is not the same thing as wakefulness now normally they go together right you can go to sleep and you might lose consciousness a bit and you wake up you come around um but there are occasions where the two dissociate when you are asleep and you're having dreams of course you're conscious when you're dreaming dream is conscious but you're asleep and on the other side there are states such as the vegetative state or the unaware wakeful state where people after severe brain injury go through cycles of sleep and wake but there doesn't seem to be anything going on that doesn't seem to be anybody at home there seems to be no consciousness happening so consciousness is not the same thing as wakefulness so what we need to do is ask what in the brain goes along with consciousness and not just with wakefulness and along among many different approaches to this and it's kind of long story very short i just tell you about one approach that that we've been following in the lab and now with with colleagues in cambridge and london who are here dan and and pedro media pedro and fernando and so on tristan uh we use this measure called lempel ziv complexity this is basically it's very simple really it sounds complicated it's really the same thing that takes a digital photo and compresses it into a short file that you can send by email and it does this basically by counting the number of repeated patterns in a photo or in any kind of data and it looks at how many patterns of comp yeah ask questions about that later complicated thing at the bottom but basically it's just saying how many different combinations of ones and zeros are there in any data set count the number of those the library that you need to recreate the original and that's the length of complexity broadly you can think of it as the higher it is the more diverse the more patterns there are in the data that you're looking at and if you apply this measure to data from from the brain rather than to a photo you see some interesting things this is work with with adam barrett and michael shartner at sussex and our collaborators under anesthesia excuse me the uh complexity level goes down when you lose consciousness your brain becomes more regular more predictable as you lose consciousness the same happens in sleep this is another data set where we recorded or colleagues recorded from electrodes planted deep into the brain what's interesting here i wonder if this is going to work you can sort of see oh yeah look at that that's clever you can see here that wakeful rest and rapid eye movement rem sleep are basically the same patterns there which means that this measure is the same for the stage of sleep when you're likely to be conscious and dreaming than when you're awake and aware but in other stages of sleep i'm going to do this all the time now it's it's much lower and then finally in what was quite a surprising finding when we applied the same measure with colleagues in imperial to data from people in the psychedelic state whether it was lsd here but also psilocybin or ketamine it does the other goes the other way the brain becomes more diverse more unpredictable in the psychedelic state this was often written up in the media as scientists discover evidence for a higher state of consciousness which is not really what we were trying to say it's something there's something measurable in the brain dynamics though that is characteristic of the psychedelic state which is interesting now these are a first step towards tracking the neural fingerprints of conscious level in the brain but it doesn't necessarily explain anything about why that happens why that should be the case and so to bring you kind of up to where we are uh with this sort of work it's trying to develop measures based on this idea but that actually in give us a principled reason for why they should go along with consciousness and this is based back in work that actually first really inspired me to do consciousness science as a career try and get into it anyway back in the late 1990s i was doing my phd and i read these papers by gerald adelman who became my boss in san diego and julio tanoni one of his proteges who's now a real leading figure in the field and they had this idea that every conscious experience every conscious experience that you have has two properties it's both integrated it's all of a piece like you don't there's nothing experiences bits of them don't go on separately from other bits right now it's all happening in one unified scene but it's also very informative so every conscious experience that you have rules out the simultaneous occurrence of a vast repertoire of alternative possible experiences that you could have it's in a very strictly technical way it's informative it's reducing the uncertainty in the space of all the experiences you could you could have these are two very distinctive things about consciousness that don't apply ever or don't readily apply to other things that about biology that we we might want to explain so we want measures in the brain that that reflect these two properties at the same time that that capture this middle ground between information and integration and this is something we've been working on in other groups two for for a number of years now and that this is still at the level of just developing the actual measures and again these are the last uh equation the only equations are going to appear in the whole talk and they're really they're not particularly irrelevant it's just to show that there are ways now to write down things that capture this middle ground and the idea is we can go and test these measures on data from the brain and see how they behave right now they don't behave as nicely as the simpler measures so there's still a lot of work to do and one of the things that we're moving on to and this is the last thing i'll say about level is to build also measures that capture emergence this is another super interesting quite controversial quite difficult to define phenomenon in which a bunch of parts like in this case a flock of starlings the flock seems in some ways have a life of its own it seems to be more than the sum of the individual birds that make it up this is a we will recognize when it happens in a situation like this but it's surprisingly difficult to figure out how you mathematically figure out where and when it's happening in other systems like if your neurons are firing in complicated ways how do you know whether it's sort of like a flock of birds or not it's quite a difficult question to ask so with lionel barnett and fernando rosas and other people here we've been trying to develop ways of quantifying that and see if that can act as also a measure of conscious level okay so this is a whistle stop tour through these things so i'm going to move swiftly on to conscious content the question of how our conscious experience comes to be populated by all the different things that it is at any particular time the objects people places colors shapes and so on and here's another demonstration to get down from the heady heights of equations and so on um oops i don't know if you've seen this before is it actually working let me see yeah there again um what i'd like you to do is focus your eyes on the black cross at the center of this image and just try not to move your eyes and try not to blink i'm going to do it too but it's a bit difficult from here now without leaving just how many people see that the magenta patches have disappeared green patch is is that this is this is the kind of thing couldn't do on zoom all last all last year just like actually ask people questions it's brilliant i love it so now blink and move your eyes and have a look around of course the magenta patch has come back there is no green patch this is called a lilac chaser illusion and what's actually happening here is a few different things there's something called troxler fading when things with indistinct edges are at the periphery of your vision they tend to just disappear from your experience there's also apparent motion when things change on and off near each other the brain infers motion between them and there's color opponency the opposite the brain has a color space and the opposite in color space to magenta is green and the reason for that actually is kind of interesting because you make magenta by mixing red and blue light but if you think about the electromagnetic spectrum red and blue and green is in the middle red and blue on the edges so if the brain gets red and blue it's sort of expecting the green uh cells to be activated too but they aren't because you're only mixing red and blue so magenta is sort of not green so when you're seeing the green after image what you're really seeing is not not not green okay good um so the way to understand that piece of nonsense is that your brain is a prediction machine you know there is this gap you can already see there's this gap between how things are and what you experience and the idea that i've been running with is that this happens because the brain is always making sense trying to make sense of what's essentially noisy and ambiguous and uncertain data now imagine being a brain for a second imagine that you're stuck inside this bony vault of your skull trying to figure out what's out there in the world now there's no sound in the skull there's no light in the skull it's dark it's silent all you've got to go on are these electrical signals which are only indirectly related to things in the world whatever they may be so perception has to be this process of inference of best guessing where the brain combines this soundless colorless uncertain sensory information with its best with its prior expectations its prior knowledge about the way the world really is and that's what we consciously see we see the brain's best guess of what's out there that's a very sort of abstract high-level description of what's going on there is another equation dammit i forgot that one what this mean what this translates to if you think what does this actually mean for the brain it means the brain is doing something called bayesian inference bayesian inference is a very old idea in probability in statistics and mathematics it's sort of reasoning under conditions of uncertainty everything is uncertain we can use bayesian statistics to figure out what might be happening in the pandemic to try and locate a missing submarine it's sort of reasoning backwards from the effects to what you think caused those effects like in this case the effects are the sensory signals that hit our eyes and our ears and the causes are what's out there in the world that gave rise to those sensory signals now actually it's usually very complicated to do for anything for you know to write it down do a computer to get any machine or anything to do based on inference is really um complicated but one way to do it one way to at least get an approximation to it is to do this thing called predictive processing and this is the idea that this is what the brain is doing when it's making a best guess and the reason it's doing it is because it's it's a way of doing bayesian inference to try and figure out what caused its sensory environment and the idea of predictive processing is very simple it's that you have signals going in both directions in the brain one is cut one direction is from the outside in from the world deeper and deeper into the brain and the other direction is the other direction from the inside out from the brain back out to the senses and back out to the world and if you take the inside out signals and think of those as the predictions those are the predictions about what's going on and the outside-in signals what's coming in and percolating upwards through the brain that's the those are just the prediction errors those are just telling the brain the difference between what it's expecting and what it's getting and by continually trying to minimize these prediction errors get rid of them update its predictions or change the data to get rid of prediction errors these predictions collectively settle on the brain's best guess of what's out there and that turns out to be uh very close to what bayesian inference is but beyond that sort of nice mathematical equivalence there's a real conceptual message here which which i still find quite puzzling to to think about i mean we're so used to thinking that perception is this process of just reading out sensory signals it seems as though the world pours itself into our minds through the transparent windows of our senses but it's the other way around what we perceive is coming from the inside out and the sensory data is just keeping our perceptual best guesses in check so perceptual content is conveyed by the top-down predictions and bottom-up sensory signals just convey the prediction errors so the green arrows are the important ones there um skip skip this we don't need that uh now if you start asking what's the evidence for any of this kind of this kind of proposal there's some and we've done some of it in the lab this is an old study now with with a former postdoc of many pinto what we do here is we showed different images to each eye so in one eye might see an image of a face that gradually appears and the other eye might initially see this changing pattern of coloured blocks which gradually fades away and if you show them to separate eyes the brain instead of combining them into some sort of mess it starts off with the most dominant so you just see the changing colours and then after a while the face breaks through and that's what you see so prediction you can make is that well if perception is conveyed mainly by the predictions by what the brain is expecting then if you cue the person the word face to expect a face then they should see a face more quickly and more accurately than when they're not expecting it and that's what we see in the data so people see more accurately and more quickly what they're expecting to see compared to what they're not expecting to see but that's kind of that's sort of psychophysics that you can do in the lab and it's it's fine but it's not really getting us that close to what our lived experience this rich panorama of perceptual experience is like so to do that one of the things we're doing in the group now i like to call it comp it's a bit of a mouthful of a term i know that but i like to call it computational neurophenomenology i mean i really should call it something else but this is just the idea of using computational models to try and build this bridge between what's happening the brain and what our experiences are like and we're doing this at the moment by focusing on unusual experiences like a good way to understand the system in general is to look at it when you push it and so it's behaving a bit differently from normal and in particular in vision we have this phenomenon of something like hallucination now this is this is a picture of a face in the cloud we're all familiar with this in some ways we see faces in clouds we can see faces and pieces of toast we can see faces in basically anything the brain is strongly wired to to to be sensitive to see faces um oh we can even see faces in churches and so what's going on here this suggests the brain has a strong prediction about faces so can we then understand can we try and simulate that somehow and this this balance what happens when you turn up the predictions a bit and so this is quite old work now with kesake suzuki and others in the lab where we took one of these very well-known neural networks this is just a neural network that takes images and tells you what's in them all the information flows from the image upwards but you can turn it the other way around and you can fix the output and basically say something like dog and then run it backwards and change the image so in that case what you're doing is you're projecting a prediction into a pre-existing image and if you do that and we did this in a in a panoramic video and replayed it through a headset so people can put a headset on and look around and what they see is a world suffused by dogs and dog parts and we call this the the hallucination machine and if you actually look at it through headsetters it's surprisingly compelling and it's not you know some people say it's a little bit trippy here and there it's probably not but it's definitely unusual and there's something going on it's not just dogs photoshopped onto this image there's dogness emerging from the image in all sorts of interesting ways and so this is what happens if you're this is a simulation of what happens if your brain has overly strong predictions to see dog so what we're doing now just again whiz through to bring up to to we're sort of taking this further and trying um to simulate different kinds of hallucinations now hallucinations a complicated concept lots of people have lots of different kinds in particular people in with parkinson's disease or certain kinds of dementia can have very complex hallucinations where there's complete scenes in people and objects and places other kinds of hallucinations can be very simple patterns and shapes and nothing nothing more than that so we have now a more sophisticated set of neural networks that we wire up in all sorts of different ways and what we can do is now simulate different kinds of hallucinations so what you see here each of these images is like a starting point um there's a bird a mushroom a lamp a volcano and a thing that's a flower some sort and um the second row down just it's a bit blurry and that's deliberate what we're simulating there is a hallucinations that happen when people lose central vision happens in something called charles bonnet syndrome and if we run the system you see that we end up with very different kinds of hallucinations in each of these cases so this is now where we can just get a bit more specific about the mechanisms that underlie different kinds of perceptual experience and i think that is some getting us a bit closer to understanding how experiences are constructed in our own brains we're also closing the loop on this uh by finding people with these conditions who experience these hallucinations in real life and just asking them to sort of match the output of the model to what they encounter in their daily life so we can calibrate you know what we're doing against what people actually experience so this way of thinking leads to the idea that hallucination is a kind of uncontrolled perception it's what happens when the normal business of inferring what's out there balancing perceptual predictions against prediction errors goes off the rails a bit and in turn what that means to me anyway and i i first heard this phrase from chris frith uh you heard it from somebody else you've never been able to find out where it originally came from is that perception perception is a kind of controlled hallucination now this is often misinterpreted as saying that perception as a claim that perception has nothing to do with the outside world that everything is made up um that you know go and stand in front of a bus people tell me and see if you still think perception's a hallucination it's like no the control is just as important here the way we perceive things is reigned in by the world in all sorts of interesting and useful ways for the organism but i like this phrase because it just underlines a continuity hallucination is not a completely different species it's the same underlying process it's just the balance between predictions and prediction errors has gone the brain's best guesses have lost their grip on the world and people see things that other people don't now in the book i try and take this idea much further than just seeing dogs on sussex campus or seeing a face more quickly and the larger claim here is that this way of thinking applies to all of our experience all of the time it applies to experiences of color of sound of touch taste but also more fundamental things like a sense of time and duration whether a visual impression feels like an object or not and ultimately whether things somehow seem real even that is an aspect of perceptual inference this experience that we have that what we perceive really exists that too just like change is another aspect of perception the image in the back was trying to just give a feeling of like a real world experience it was one of the few summer days in brighton that was beautiful out on the water and the next part and for me the most interesting is when you take these ideas and turn them inwards to the self and to recognize that the self is also a form of perception now it's quite natural to think maybe that the self is the thing that does the perceiving that you have a world out there the sensory data comes from the world there's a self that's somehow the recipient of this data that forms perceptions that reflect the way the world is but it's not really like that i don't think it's like that at all the self itself is another form of perception it's another kind of controlled hallucination but a very special one because it's the experience of being you now the first implication of this is again not a new thing it's just the self is not one thing this is another little division between how things seem and how things are so it might seem to us in our normal lives unless we are suffering a mental illness of some sort or something that the experience of being a self is unified there's just you and you go along from place to place or zoom meeting to zoom meeting and it's the same you that's there along for the ride all the time but there are many ways in which we all experience being a self there's the bodily self the experience of being a body just being alive and identified with this thing this thing in the world this object that is your body there's place where your body ends and the rest of the world begins there's the experience of perceiving the world from a first-person perspective somewhere behind your eyes maybe we know this can go away because people report things like out of body experiences where they see themselves from an external perspective there's the volitional self the experience of making actions deciding to do something being the cause of things that happen in the world people often think this well free will is related to this we can talk about free will later it's a bit of a rabbit hole and then finally there's there's higher levels of self there's something like the narrative self where self becomes associated with a set of memories with a persistent identity over time a name and then there's the social self this thing i think many of us have been missing this part of us that depends on being with others part of what it is to be me is refracted through the minds of the people that i know that i interact with and all of these different aspects of self all seem to be bound together all seem to be part of a piece but they can come apart in all sorts of ways and we know this from especially i think the the writings of people like oliver sacks are beautiful illustrations of what happens when one part of the self is changed but the other parts might might remain in the book i talk about a person called clive wearing clive waring is a musicologist and he had a very very severe form of amnesia a very severe brain disease which led to one of the most dramatic and profound amnesia's losses of memory that's ever been recorded he could not remember anything new he lived in what was called a permanent present tense of about 10 seconds for years in his 80s now this happened in in the 80s um but the rest of him is still there and there was a i never met him i knew this second hand but there was this famous uh event where he he went back to a choir that he used to direct and he was able to direct the music with the fluency that made him seem whole again i think it's a it's a wonderful story i'm going to talk a little bit about the bodily self this is where we've done i think the most uh my interests have focused in our groups this is the experience of of both identifying with this object in the world that is your body and a more basic experience of just being a living organism without shape or form now the idea of course is that these experiences of having and being a body are perceptual constructions are brain-based best guesses just like everything else and there's a very famous illustration of this which i think many of you might have seen called the rubber hand illusion what happens in the rubber hand illusion is that a volunteer in this case the guy in blue hides his real hand is hidden behind a partition he can't see it and a fake rubber hand is placed in front of him which you can see then the experimenter the guy in green takes two paint brushes and strokes both hands simultaneously and what happens for many people not for everybody but what happens to many people when you do this is that they report this somewhat uncanny feeling that the fake hand is sort of something maybe a bit like part of their body um not completely but maybe a little bit and if you stroke them out of time that that doesn't happen so this has been in fact i use this in a lot of talks it's like or i used to as a fantastic example of the brain making a best guess about what is and what is not its body you can just see it happen here i forgot to start in the movie uh it's always fun to look at there they're stroking it and there's a way to test whether it's actually worked which is to use a kitchen implement so yes it worked look at that uh so there's a sort of nice story here where where you can think that the yes the brain is getting evidence that all the sensory information is coming i see it the brain is seeing a hand it's feeling touched the hand looks roughly like a hand as where a hand should be so it's making its best guess now this might be part of the story but what but one of the fascinating um lines of work that that's been happening at sussex especially with my led by my colleagues pete larson and zoltan dienes is that that's not the whole story in fact that might not be part of the story at all pete embarked on the world's largest rubber hand study probably a couple of years ago doing the rubber hand illusion on about 400 undergraduates in these kind of rubber hand factory farms that were was set up at sussex at the beginning of the the pre-pandemic academic year so we did the rubber hand illusion on a whole bunch of people but at the same time also measured something called suggestibility now you've all heard of hypnosis right and hypnosis isn't just stage trickery we all differ in how suggestible be we are there's a tendency we all have that if somebody encourages us to do something or to expect something to happen or expect or to experience something if we're highly suggestible we'll be more likely to do that thing we'll have that experience and it's a very stable trait and it turns out that this correlates quite strongly with the rubber hand illusion so you can see that line that's a that's not a statistically appropriate line i photoshopped on uh to the graph from the paper just it goes up that way but basically the more suggestible you are the stronger the rubber hand illusion is now those those two color bars here because that's comparing when you stroke in time and out of time and you might say aha but there's still a big difference um well yes but in fact and this is other important work that pete's done people expect there to be a difference if you if you just tell people what you're going to do in the rubber handles i'm going to stroke your hands either in time or out of time what do you expect to feel people know what they should experience and so it's actually no surprise that there's always a difference between them in psychology this is the very old issue of demand characteristics that we always worry about how do we control for what people expect to happen because people doing psychology experiments are really annoying they always try to figure out what you want to happen and either do that or more likely do the opposite um but all this is part of the part of the same thing it's saying that that what we experience is still this this construction but there are many different factors now there's not just the sensory data there's all the things that the brain is bringing to that context to expect okay now in the last bit of the talk i want to talk about not the experience of the body as an object but the experience of just being a body this basic basal ground state of what it feels like to be alive i call this this idea of being a beast machine which i'll explain why in a little bit so having a body is one thing and by the way there is i mean there is something really distinctive about that in other cases we know from lots of neurological cases there are cases like there's this thing called somatoparaphrenia where people who've had a specific kind of brain damage they will experience their real limb they have you know they still have a maybe a right arm they will experience it as belonging to somebody else and that experience is held really powerfully they will try and throw themselves out of bed they may they they just do not believe it's their arm even when you point out that it's joined to their shoulder so that's the sort of strength of experience that you never get in something like the rubber hand illusion um so it's this this body ownership thing is it's fundamental to the self but there's also this experience of just being a living organism and we don't think about this quite so much or at least i didn't used to think about this this so much but i think it's really at the bottom of what being you is is all about and it highlights another form of perception we're very used to thinking of perception as something that's mainly about the outside world you open your eyes you can listen it's figuring out what's out there in the world but there's a whole variety of perception called interoception and this is about the brain perceiving and regulating the interior of the body if you think about again what it's like to be a brain it's got no direct access to anything whether it's in the world or in the body all it gets is sensory signals electrical signals they don't come with labels like oh i'm from the heart i'm from the kidneys it doesn't work like that um so this concept of interception refers to all the various ways that the brain senses uh its own physiological condition and if you think about it that's fundamentally what brains need to do you know they're not there to write poetry however nice that is or or figure out marketing plans for the following call circles they're there to keep the body alive but how do they do that well they're faced with the same problem there's no direct access so this perception of the body from the inside follows the same principles at least this is what i think is going on that it follows these principles of prediction and prediction error but now this dance between prediction and prediction error is unfolding primarily within the body itself this is this concept of interreceptive inference and there's one crucial difference between perceiving the body from within and perceiving things out there in the world like this this glass of water which is that interreceptive predictions these predictions these perceptions predictions about the body they're not about finding things out they're much more about controlling things so what matters about the state of my body from the brain's perspective is not where my lungs and kidneys are and what shape they are what color they might be but how well they're doing their job at keeping me alive now and in the future whereas when i perceive the outside world i mean ultimately that's what it's for too you know my vision works ultimately in the service of me staying alive but more immediately yeah i need to know where things are is it coming towards me is it going away is it going to eat me whatever so interceptive predictions are basically doing a fundamentally different thing and i think that's underlies why the perceptions of the body from within feel very differently have a very different character than experience of the world around us when we think about experience of the world around us it's objects in places and people and things and smell but these embodied experiences emotions and moods things feel good or bad or more likely to be good in the future or more likely to be bad in the future i mean that's a pretty limited view of emotion but it kind of comes down to that things are ultimately good or bad in some way now this this idea it brings together and in the book go into this a bit more is that brings together a lot of different ways of thinking about the brain there's this very i think for me hugely exciting but much overlooked tradition called cybernetics back in the 1950s when people were first thinking about computers they weren't only thinking about computers to play chess or to play go or do reasoning there was another completely integrated at the time line of thinking about systems that could control things like it was just after the war so things like radar and guiding missiles were critical this idea that a good control system has to have tightly coupled feedback it has to be very sensitive to error prediction prediction and it also has to have a model of the system it's controlling has to be able to make predictions about it need to know what's going to happen to it in the future so the idea is that any control system worth its salt in a complex situation is going to involve this process of prediction now your central heating system at home or air conditioning system for the audience in america is um can work very simply like if you if it's too cold it comes on if it's too hot it turns off but when it comes to something like the body it's not enough to do that you don't want to wait until your heart rate has gone through the roof before you decide to try and dilate your blood vessels or do some other thing or your brain decides to do that you have to predict in advance in order to keep things stable in physiology this is called allostasis achieving stability through change so this this idea has a very long provenance that motivates this idea of predictive perception from the perspective that that's how we the brain controls things this reaches i think it's it's sort of most fully elaborate and beautiful um apogee in this idea of the free energy principle which was developed by by carl fristan who's also here and this is the idea that pretty organisms especially organisms are basically things anything that counts as a thing maintains itself over time doesn't dissipate into no into nothing in organisms or things that maintain themselves over time just think about like a fish a fish swimming around in the water remains being a fish because it's in the water if you take a fish out of water and put it on the table it you know dissolve into mush after a while living systems in particular maintain themselves in states they expect to be in in a long in the long run they try and stay in a very small repertoire of possible states they could inhabit i am not turning into mush and my brain's job is basically to try and keep myself in this very small state of all the possible states i could be in most of which would be mush and it turns out this very basic imperative just to remain being a thing gives rise to this rich machinery of prediction and prediction error and control so just to summarize this this last bit then and i think i've already hinted at this but the the reason this is particularly relevant for consciousness is that these different kinds of prediction explain why different perceptions are the way they are visual perception underpins visual visual prediction under underpins visual perception we see objects in places because that's what matters that's the character that's what visual predictions are all about interceptive predictions underpin embodied experience how well things are going things going badly am i anxious am i out of running over time or not um those have a very different qualitative character but i think it all comes down to the different kinds of predictions at play and this brings us back to to where we started this idea of self-change blindness i experience myself as relatively stable over time even given good photographic evidence for the contrary why is this like it's happening right but why is it happening well i think one reason for this is that if the predictive perceptions in my brain that are geared towards keeping me alive for them to work well they basically expect me to stay stable they expect me to not change over time the stability of the self becomes a self-fulfilling prediction because to remain in to remain stable to remain alive i predict myself to not change the subject we are subjectively blind to the changing self for this reason and this applies not only and this is this is conjecture this is not i'm not trying to say this is like oh we've got this experiment prove this no i think it makes sense and um and it's the way i've come to think and it applies not only to these basic experiences of just being a body but to all our experiences of being yourself there's something very useful if if the brain is trying to keep the body going for a long time to experience the self as unified as stable is a good way to make sure that what the organism does is always drawn to that as the most likely outcome so the subjective stability of the self as a whole becomes a self-fulfilling prediction we predict ourselves into existence so let me just wrap up where we've been what we consciously see depends on the brain's best guess about the causes of sensory signals in the rubber hand illusion and other experiments of this sort hints that this applies not just to the world around us but to the self but of course we have suggestibility and all these other explanations too but the experience of self is also a thing and that the predictions that matter for the body are not just predictions about the body as an object but about controlling and regulating the internal physiological state of the body this means to me that all our perceptions they're all grounded fundamentally in this imperative to stay alive these predictive mechanisms that arose over evolution and development all have their origin in this primary imperative to keep the body going we perceive the world around us and ourselves within it with through and because of our living bodies this means again that consciousness actually is really quite closely related to life it's not just a historical analogy anymore there's a close relationship between being alive and being aware and this is where we can finally bring up descartes who always has to make an appearance in any to unconsciousness but it's not because of his dualism here it's more because of what he said about the relationship between life and mind and he said about other animals and i always feel bad about giving him stick because he was living at difficult times and he was brilliant but he did say this about animals without mind to direct their bodily movements animals must be regarded as unthinking unfeeling machines that move like clockwork so being alive was irrelevant to the sorts of rational conscious minds that humans had now i think it's entirely the other way around conscious selfhood arises because of not in spite of our beast machine nature now finish in the last couple of minutes with just a couple of implications from this that are drawn out in more detail in the book of course uh one is free will free will is something that you know we can talk about consciousness and how mysterious it is but free will sometimes seems another level of mystery altogether does it depend on whether the world is deterministic or not well free will is just another kind my view anyway free will is just another aspect of the perceptions that make up being a self it's the perception of being the core it's the perception of making actions that appear to come from within when we experience a freely willed action it feels as though we're making something happen that needn't have happened or i could have done differently or the world i'm intervening in the universe in some way that doesn't mean that that's actually true in the same way that when i experience red it doesn't mean that redness is really there in the world it means that's my brain's way of making best sense of what's going on voluntary actions are real we do things that have mainly internal causes but there's no need to postulate some uncaused cause that swoops in from wherever and changes the causal structure of the universe that is spooky nonsense the second implication is that we all see the world differently now we know this a little bit at the extremes we might say somebody with psychosis or somebody with synesthesia or something that experiences colors when they see black letters but i think we all experience the world differently and that difference is often un unseen to us it's hidden because we use the same words often to describe the same things but those things as they appear to us are going to be subtly different we inhabit our own unique inner universe and beyond the human there's a vast space of other minds i spent a week with octopuses back in 2009 um which is one of the most amazing weeks of my of my scientific life and i write about this too when you spend time with octopuses you realize that the particular way that we experience being a self just doesn't apply to a creature as alien as the octopus that can taste with its suckers and that its arms are almost like autonomous animals and also has three hearts and jet propulsion and blue blood they're very strange and finally there's the prospect of intelligent machines some people think that as ai continues to get smarter and smarter there'll just come a point where the lights come on and it becomes conscious now i don't think this is true at all if consciousness is tightly bound up with being alive that's what that's what matters intelli consciousness is not the same thing as intelligence that's just part of our human centered hubris where we think we're intelligent and we're conscious the two must go together you don't have to be sentient to suffer no you don't have to be smart to suffer but you may have to be alive i love this alex garland film x machinima which explores these ideas about when we infer consciousness in other things so if we are worried about creating consciousness artificially perhaps we should be more worried about things like brain organoids this new neural technology where people are growing brain-like structures in a dish um this is rapidly advancing and there was a paper that i just saw uh the other day with a conscious organoid here i've i've didn't actually do that and that was my sort of messing around with keynote yesterday but this organoid actually has light-sensitive pits you know the the beginnings of eyes and the neurons within it respond now these are still relatively simple but they're made out of the same stuff they're not made out of silicon so one whole big unknown about what it takes to be conscious just isn't there anymore um with my colleagues tim bain and my cell massimini we've written about the prospect of islands awareness and there's another case with michael carter who's here as well where we think about patients who basically have had operations that leave a hemisphere of their brain alive but disconnected within the skull and on that cheery note i just returned to the core message which is that we perceive the world around us and ourselves within it with through and because of our living bodies and before closing i would really like just to thank this is of course the way i've you know all the work that i've that's happened in the lab has been done by other people and i've been so fortunate to work with a brilliant lab over the last 10 or 15 years at sussex but it's also shaped the way i think about everything too it's not just the experiments the ideas that have all come as a as a collective so i want to thank everybody i've worked with and the last thing i'd say is that i know it's a bit unusual but the book is dedicated to my parents of course but i just wanted to dedicate this particular talk to a former phd student of mine paul chorley uh paul died in 2013 shortly after finishing his his thesis and and though some of you here might remember him a bit he was a lovely man and a brilliant a brilliant intellect too and i just uh he sadly missed and i wanted to keep his memory alive a little bit so this talk is for paul and i'll leave you with this summary of everything and thank you very much [Applause] you

Channel: The Royal Institution

Views: 946,627

Keywords: Ri, Royal Institution, anil seth, cognitive science, neuroscience of consciousness, your brain hallucinates your conscious reality, free will, consciousness, brain, illusion, neuroscience, royal institute, science talk, psychology

Id: qXcH26M7PQM

Length: 64min 4sec (3844 seconds)

Published: Thu Dec 02 2021

Reddit Comments

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[u/netsec_burn]

What would be the difference if it was?

[u/ImoJenny]

TL,DR: There is one bit worth further research, but overall the speaker lacks coherence and distinction (lol), his points aren't original, and he appears to have missed a great deal of relevant literature.

Not promising that they're trying to hide the ball with the shift from he hard problem of consciousness to the "real" problem of consciousness before the speaker is introduced, and the speaker starts by leaning hard on a definition. I also don't appreciate that he is essentially throwing out not only thousands of years of philosophical works on the question but also the works of Merleau-Ponty, Penrose, Hameroff, and many other modern thinkers who have approached the subject.

About 12 minutes in he starts getting into Varela & at least has the courtesy to give credit to him but now he's undercut his previous sweeping assertion...

The application of Lempel Ziv complexity is interesting but as with most neuroscience we are capable of with current equipment it is still observing epiphenomena. I think it's telling that he is forced to speak broadly about "information" without providing a firm understanding of qualitatively what that information is. Not all information is interconvertible. This might just be my soap box but I think the observations he provides fit well with a ToC that is based in (gasp) quantum coherence.

Then he dives into demonstrating that immediate perception is generated in the mind. This isn't new & it isn't "high level." (see above referenced thousands of years of philosophers & literally any magician)

36 minutes in and he finally disavows the claim being made by the clickbait. I really don't expect anything else interesting from the lecture but I've been disappointed by The Royal Institution before and I think at the time that I might be biased.

Finally he gets into the main thrust of his argument: That the self is hallucinated while conflating this with being fabricated. Sounds like he didn't actually read his phenomenology as well as he thought he had.

I'm a little thrown off by his obsession with static self-perception. I... really don't think that he can claim that this is a universal or even that perception of self as non-static is all that uncommon. When I was in school we often talked about where one draws the line of what encompasses self. I would suggest that the speaker is leaning on an over-concrete and a sort of "all in or all out" delineation of self.

It's almost redeeming that he takes a dump on Descartes at the end but he does so in a way that props up the old fool. Then he has to go and make mushy commentary on the intrinsic link between being living and being conscious... which of course he doesn't back up in any way.

All in all, not really worth watching past the Lempel Ziv measurements & I would like to see those write-ups specifically rather than predigested through this. I would advise against putting too much stock in The Royal Institution. Their lectures are pop-science and more often than not have poorly backed claims or even outright fabrications.

[u/psychopompandparade]

Oh are we playing language games again? What is a hallucination? Wouldn't the self, as not a strictly sensory experience, be a delusion, rather than a hallucination? And wouldn't all vision be a hallucination, in a sense? And who is having the delusions? Is it a hallucination if a tree falls in the forest and there's no self to hear it? Mostly we're playing with the definition of words and working around a language structured around an assumed consciousness as well as assumed agency. It's near impossible to use language to express a full lack of self or free will.

[u/RelentlessExtropian]

I'm gonna go out on a limb here and say "no"

[u/SmileTribeNetwork]

No.

[u/ImoJenny]

Title is clickbait, the speaker admits as much about two thirds of the way through when he discounts it as a misinterpretation of a much less controversial position.