Q&A - The Neuroscience of Consciousness – with Anil Seth

[Music] thank you so much for that excellent lecture it raised a lot of questions for me one of which I would like right into asking two parts if I may which is to ask you about the relationship between consciousness memory and identity and in the second part the relationship between conscious individual consciousness and collective consciousness thank you the relationship between conscious and memory I think is is it's very complex and it plays out in many different ways partly because there are many different kinds of memory one of the most obvious contexts this plays out in is an episodic memory so that the memory of past events that are personally relevant to you where you were yesterday where you were a year ago and one the some I didn't focus on it today much at all but there's some very famous case studies in the medical history many of you might have heard of the patient HN who had his hippocampus part of the brain that's responsible for laying down these episodic memories removed so for many decades HM could not lay down any new memories this had the effect that he was kind of living in this presence all the time he still had other kinds of memory he could learn new motor tasks learn to draw and so on but he's sort of personal narrative his narrative self kind of stops at the moment that he had that that surgery this doesn't mean he lost consciousness what it means is that he he was clearly still conscious for the rest of his life which lasted many decades but the one specific part of being a conscious self was no longer was no longer there there's another case Clive we're in he much the same thing due to a disease rather than the surgery and he was he had to expend serving a seven-second memories to start with and that was it he lived in this present it also meant that he couldn't when when you can't remember episodes in the past it's also more difficult to project yourself out into the future so it's as if there's this symmetry that memory is really about the ability for mental time travel to the past or the future but what essentially you still you still are conscious and many of your aspects of being a conscious self are preserved you still have a first-person perspective you still have a body you still feel in control of your actions but one aspect has gone so memory I think plays a significant but it's a role but it's not completely essential and the second question very briefly between individual consciousness and collective consciousness well the consciousness I don't think there's anything like a single conscious entity made up of lots of people however I think it's very clear that the way I experience being me does depend on how I experience others as experiencing the other people are the most salient objects in the world now of course that's not always the case and I know there are some experts in this audience on conditions like autism where that seems to be somewhat different that it's perception of others and mental states might not come so naturally but again it's not it's not that people who perceive others mental states less clearly are in any sense less conscious it's just their conscious self is a different kind of thing is there any one's bit further Apple is going to perhaps the gentleman on the other side actually sorry that's within the blue shirt thank you anteye sorry I was interested in your comment about octopuses in their arms which do you have complex neural networks and also relating that to the experiments on humans we've damaged the corpus callosum where it's often the case that one side of the brain seems to be aware of facts about the outside world but the other side is not is any evidence that brains can support discrete separate conscious subsystems but there's more than one consciousness within us being a brain it's a very very good question and perhaps the best evidence of something like that is in these so-called split brain patients who had their corpus callosum severed in order to relieve intractable epilepsy and in cases like that indeed you would you would sometimes see a dissonance between the two cortical hemispheres when we try to stop the other from doing something the difficulty in interpreting something like that is that um is that usually only one hemisphere was reporting what was going on because language is often lateralized however ie I it seems it seems entirely possible to me that that you can have two consciousnesses within within one skull and there's another kind of opposite example there are very rare cases of people of twins born with with their skulls fused together so they have almost separate bodies but now they're sharing a brain and there's very interesting questions there about well what what's the is there a single conscious self in that situation I don't know the answer to that but anything there's anything in principle even within a you your your brain now in my brain now there is the possibility that that there may be part of my brain supporting conscious contents that other parts of my brain don't know about and there's some quite difficult arguments that you can have there about is can my visual cortex be conscious of something without the front of my brain knowing about it the problem is how do you do an experiment to test that let's take some questions on this side and in front-load please first you mentioned in your talk about the idea that one's perception of one's self usually is somewhere in in your body usually comes about there can you show any light on what you know why we sometimes feel we're not there where from somewhere outside the body so this is a question about alpha body experiences perhaps I think it's a great question because it's easy to dismiss something like an out-of-body experience that's just inconsistent with the precepts of science it requires some sort of dualistic idea that the soul has left the body and is floating around somewhere I think yeah well that's not what going on but it's also not of the right way to think about it people report out-of-body experiences so let's trust their reports but let's come up with a better explanation for for what might be going on now it turns out you can induce out-of-body experiences in the lab and you by extensions of things like the rubber hand illusion for instance if you wear a VR headset and have a camera behind you so that the input you're getting is of your own of the back of your body and then you do this simultaneous stroking business again some people will perceive their first-person perspective as having shifted to a point behind them and in fact if you or I wear these VR goggles and we swapped the inputs so I see myself through your eyes and vice versa and then we shake hands then we might also experience an exchange of self location there are many different kinds of in without these experimental manipulations people report a graded series of out-of-body experience as well there's autoscopic Colusa nations where they see their body but they still feel their body to be where they are and then halo2 scopic situations where you feel that your self location is changing between where you are and where you perceive your body double to be and only Dostoyevsky was very troubled by this but at heart i think the same mechanisms apply that we our brain gets information about where it makes most sense to locate its first person perspective and that's where we see the world from and it's normally where we are but but there's nothing hard and fashion if there's sufficient evidence against that well go with the evidence ok so I'd like to ask someone up in the gallery just there see see white centrally thank you for a fascinating lecture and I was really struck by your perspective of unconsciousness I predict myself therefore I am and what's striking to me about that perspective is that it is as fully applicable to us human beings as it would be to an autonomous robot that exists right now yet as as conscious living beings our experience of consciousness seems to be essentially different from that of a robot is there something essential that the predictive almost mechanistic view of consciousness is missing I think there is actually this idea of predicting oneself points to one of the big differences between robots as they are now or even as we imagine they might be in a few years and us because sort of more standard view might be okay well you've got a robot it's got a very fast computer in there and you've got to have run the right program and it will be conscious and it's all about how it processes the external things in the world most robots or machines that we build don't care about their own persistence over time they don't have predictive models that are in the business of preserving some sort of deep deeply physiological integrity about themselves they like a physiology and I think that you there is no reason why we do not we cannot build systems that have if you like a kind of physiology that care about their own persistence and where everything else follows from that that the way they perceive the world becomes a consequence of a more fundamental imperative to stay alive but that's very different from the kinds of machines that we're building at the moment the question is if we were to build such machine would it would it be conscious the answer to that is I don't know I don't think that in itself is sufficient either because that's still a functional description of what of what's going on but certainly by building systems like that will sharpen our intuitions about what other remaining differences because you only by building something do we really understand how it works over the side now just okay just relate to my credit company you mentioned when consciousness arises and babies so has there been a lot of experiments done in this area about there when you're born to develop a sense of self-awareness and what this can tell us about the development of the brain and consciousness there's been a lot of work done on on on some specific aspects of consciousness in infants and especially the development of self-awareness their classic method there is the mirror of self recognition tasks you when does a baby recognize that the image in a mirror is of itself and not of something else another test this is actually also applied to animal non-human animal consciousness - and we get those discussions but the consensus that takes at least a year possibly two years before you have something like that anymore there's been surprisingly little work done on other aspects of consciousness in babies for instance their ability to be perceptually conscious to be conscious of the visual scene some works been done by a group led by Syd cuidar in Paris where they look for some of the same zero physiological markers that we know exist in in adult humans when we consciously perceive something there are things like a we call a p300 which is a Cygnus assign in the EEG 300 milliseconds after a brief stimulus if that's there in adult humans that's a good sign that we've come we've seen something if you look in in leting neonates and newborn babies you see something which is intriguingly in the middle you know in some cases you'll see a late slow response in the EEG it doesn't look much like it doesn't an adult human but it's also suggestive part of the issue there is that the the newborn brain is very very different from the adult brain and one thing is there aren't any of these there are very few of these fast connections linking long range different parts of the brain together so you wouldn't expect to see the same thing anyway but I quite like William James idea about what it is to be a baby which is that we we have to learn so much about how to interpret sensory data in fact we probably have to learn that the different senses are in fact different and he called the world of the newborn that's blooming and buzzing confusion as if we haven't developed the predictive models at that point to distinguish what's visual from what from what tactile from what's auditory I'll just take one more question actually over the side I think because I was only one over the side I'm trying to be fair in terms of the sections of the audience gentle with the versus hand up yeah brilliant and and fascinating just um I heard Daniel Dennett speak here who made the point that there wasn't a hard problem of consciousness and I thought that was interesting because obviously you know does a microorganism move from the light to the dark or vice versa is that a level of consciousness there's a clear development going upwards as you correctly said chimpanzees and evidence dolphins and recognize themselves isn't it just an evolutionary development rather than some sort of you know humans obviously think they're special but I mean they were homos you know a whole load of other species that would have recognized themselves and had that internal recognition and so so why do they called it hard problem and do disagree with Daniel Dennett now you say the easy question for last right that's that yeah I think just a couple of responses to that I think one of the reserve is this resistance to thinking that that we can explain consciousness because it's it will so in one way make us less special but that's always been the thing with humanity we try to cling onto this idea that was somehow special and different and we aren't really that different all that special but that's a good thing rather than a bad thing now is there a hard problem to agree with done it with I read Bennett's book when I was an undergrad in 1991 consciousness I explained it's brilliant it was kind of unfairly critiqued as consciousness explained away by a lot of people because there's this there's this yeah this set of arguments which I think try to convince you that when we if we're trying to understand how consciousness happens we're trying to solve the wrong problem and that we may have the wrong intuitions about what the explanatory targets of the science of consciousness should be and I think his argument there it can be very good about what might be reconstructed post-hoc to me we when when is our conscious experience happened as it happened now is it partly reconstructed from the past partly projected into the future but a wise friend once told me that you should always listen to philosophers questions but never to their answers [Applause]

Channel: The Royal Institution

Views: 31,420

Rating: 4.9266572 out of 5

Keywords: Ri, Royal Institution, anil seth, consciousness, science, neuroscience, lecture, talk, Q&A

Id: n-n1ClDhVdA

Length: 16min 33sec (993 seconds)

Published: Wed Feb 01 2017