Iain McGilchrist - The Divided Brain and the Making of the Western World

[Music] I want to talk to you today actually about the nature of existence and I will be doing so in relation to the brain not because I think the brain is somehow a more real or fundamental way of looking at things or gives us the truth about ourselves and life but it can at least cast some light I think on the nature of our thinking and the limitations of our knowledge um I suppose in the way we're sort of stuck aren't we with two models that seem very typical of our age one um which lingers in biology is of a sort of scientific materialist one which views knowledge is gained by making certain one fact and then adding to that and one builds up a picture of an external world which is independent of our knowledge and of which it's our duty to to become aware almost as though we were machines that were passively receiving information but of course the other is the postmodern flipside which is that you know it's all reality is really just in our heads and we make it all up now I think that some neither of these is particularly likely and they seem a bit crude um and I I think the the first point that one would make really is that reality changes with the nature of the attention that we pay to it attention might sound a bit dull but actually it's part of the process of creating whatever it is that we encounter in this world and things change when they put them put into the center of the spotlight of attention they also change when they're taken out of context something well it could I learnt when I was looking at works of art and literature and that they they become something completely different once they're taken out of that context if you take this might sound a little bit so abstract but if you think of something like a mountain it can be for a speculator it can be a source of wealth for a sailor it could be a landmark for a painter it might be a many textured form for the inhabitants of a land it might be the home of the gods which is the real mountain there isn't a real mountain that is separate from those different if you like interactions of us with the world although science sort of suggests that there might be one which is the one in which we play least part and so context is very important and indeed it's not just important in things like works of art it's important in physics we know that probably things that exist in terms of you know at the particle level and have their existence in a context and arise out of that context and the human genome project we're now realizing that it's not as simple as this gene codes for that it codes for something depending on the context that it finds itself in context is everything in understanding and it is in philosophy Jewry John Dewey said that neglect of context is the greatest single disaster which philosophic thinking can occur taking things out of context and of course when they're in context they need to remain implicit so many of the things that we understand we need to understand implicitly we picked them up implicitly we conveyed them implicitly and when we made them explicit we changed their nature in talking about the brain I want to remind you of a little story in Nietzsche he speaks of a wise spiritual master who governed the community so well that it flourished and as it grew he realized that he not only could not deal with all the concerns of state but that it was very important that he must not get involved with aspects of them if he was to retain his ability to see things that were of the utmost importance so he appointed his brightest and best minister to be his emissary and to go abroad during his work on his behalf the emissary soon began to feel that he was the one that did the real work and that his master was irrelevant he took upon him the Masters cloak assumed his authority and deposed the master unfortunately he didn't know what it was that he didn't know as a result both master and emissary and the realm they both served fell into ruins bear that in mind while we talk about things this picture famous picture of esters is their release to suggest that we don't begin with one thing that's certain and build on that but that things come into being through a kind of interactive process the attention we pay to the world changes what we find there but what we find there changes the attention we pay similarly we can't understand something by knowing one little thing out of context and adding another little thing out of context we need to make a bit of a leap as as as in the business of attending there needs to be a kind of sense of what it is we are dealing with because we need to apply a certain model we only understand things by comparing them with something else we think we know even better and in the case of consciousness and in the case of the brain it's difficult to know what that model would be when we don't think about what model we apply we automatically go to default the Machine the division of the brain is something neuroscientists don't like to talk about anymore it enjoyed a sort of popularity in the 60s and 70s after the first split brain operations and it led to a sort of popularization which has since been proved to be entirely false and it's not true that one part of the brain does reason and the other does emotion both are profoundly involved in both it's not true that language resides only in the left hemisphere it doesn't important aspects are in the right it's not true that visual imagery is only in the right hemisphere lots of it is in the left and so in a sort of fit of despair people have given up talking about it but the problem won't really go away because this organ which is all about making connection is profoundly divided I didn't make the division it's there inside all of us and it's got more divided over the course of human evolution so the the ratio of the corpus callosum the band of tissue that you can see there the right hemisphere has been pulled aside in this drawing to show you this band of fibers that connects the hemispheres at their base and the ratio of the size of that to the volume of the hemispheres has got smaller every evolution and the plot thickens when you realize that one of the main if not the main function of the corpus callosum is in fact to inhibit is to inhibit the another hemisphere so something very important is going on here about keeping things apart from one another and not only that the brain is profoundly asymmetric now I'm not going to go into all the the information in this slide and just to help you orientate yourselves you're looking at the bottom of the brain there you're looking upwards which is why the right is on the left and the left is on the right just to make it a little bit easier and what it shows is that there are a symmetries in the brain principally it's broader at the back on the left and broader on the right at the front and slightly juts forward and backward at those parts as well and it's as though somebody got hold of the brain from underneath and given it a sort of sharp twist clockwise now what is all that about if one just needed more brain space one would do it symmetrically the skull is symmetrical the box in which all this is contained is symmetrical why go to trouble to expand some bits of one hemisphere and some bits of another unless they were doing rather different things what are they doing well it's not just we who have these divided brains birds and animals have them as well and so I thought it might be a good idea to have a look at what we know about lateralization of the hemispheres in birds and animals and it turns out that this has to do with attention and I think the simplest way to think of it is if you imagine a bird trying to feed on a seed against the background of a brittle pebbles it's got to focus very narrowly and clearly on that little seed and be able to pick it out against that background but it's also if it's going to stay alive it's got to actually keep quite different kind of attention open it's got to be on the lookout for predators or for friends for conspecifics but for whatever else is going on it seems that birds and animals quite reliably use their left hemisphere for this narrow focused attention to something it already knows is of importance to it and they keep their right hemisphere vigilant broadly for whatever might be without any commitment as to what that might be and they also use their right hemispheres for making connections with the world say would they approach their mates and vonda their mates more using the right hemisphere and one can see this because of the way the eyes are related to the hemispheres so that is interesting as a starting point but then you come to the humans and it's true that actually in humans to this kind of attention is one of the big differences the right hemisphere gives sustained broad open vigilance alertness where the left hemisphere gives narrow sharply focused attention to detail and people who lose their right hemispheres have a pathological narrowing of the window of attention but humans are different the big thing about humans is their frontal lobes and for those of you who are not neuroscientists you might think the frontal lobe was just this bit of your brain so somewhere up here behind your forehead but it isn't it's about 35% of your brain it's an enormous ly large chunk of your brain and the purpose of that part of the brain to inhibit to inhibit the rest of the brain to stop the immediate happening so standing back in time and space from the immediacy of experience and that enables us to do two things it enables us to do what neuroscientists are always telling us we're very good at which is outwitting the the party being Machiavellian is the word and that's interesting to me because that's absolutely right we can read other people's minds and intentions and if we so want to we can deceive them but the bit that's what was curiously missed out here is that um it also enables us to empathize for the first time because there's a sort of necessary distance from the world um if you're right up against it you just bite but if you can stand back and see that other individual is an individual like me who might have interests and values and feelings like mine then you can make a bond there's a sort of necessary distance as there is in reading too close you can't see anything too far you can't read it so the distance from the world that is provided is profoundly creative of all that is human both the Machiavellian and the irassman now to do the Machiavellian stuff to manipulate the world which is very important we need to be able to use interact with the world and use it for our benefit food is the starting point but we also with our left hemispheres grasp using our right hands things and make tools we also use that part of language to grasp things as we say it pins them down so when we already know something's important and we want to be precise about it we use our left hemispheres in that way and to do that we need a simplified version of reality it's no good if you're fighting a campaign having all the information on all the plant species that grow in the in the terrain of battle what you need is to know the specifics of where certain things are that matter to you particularly and so you have a map and you have little Flags it's not reality but it works better for some purposes one of the things about the right hemisphere is that because it has this broad open attention and because actually it's more integrated with our bodies it seems to have the vividness of experience fresh before it it has what Heidegger calls presencing whereas the left hemisphere takes that information and uses it disposes it in a clever way simplifies it and it represents it and one way of talking about this is over of something a bit like a map of the world which which has its uses and language can be part of that map it's tokens for things words for realities and in the left hemisphere of the brain one has one sees this representation going on now this I wanted to show you very very reef leave some pictures this is with one hemisphere inactivated at a time so on the Left you've got a tree drawn by both hemispheres in the middle you've got the left hemispheres version notice the left hemisphere is only interested in the right side of space and you can see this on any acute medical ward with somebody who has a right hemisphere stroke they may neglect anything on the left because it's not abuse to the left hemisphere it's only the bit that it's interested in using and you can see how exuberant the you can see how exuberant the tree by the right hemisphere is this is flowers a similar picture reduced to symbols tokens by the left hemisphere and these are all drawn by the left hemisphere and as you see on the left you have a cube but it has no depth you have a table similarly you have a tree reduced to a few lines you have a person reduced to a formula and you have a flower there which is a purely symbolic flower so that is the nature of that kind of reality here I just show that the right hemisphere has much more depth less a symbolic representation more the actual in-depth experience and here is an illustration from a book of Gazzaniga sharing after an operation that's the lower lower level after the coma sirata me that's when the corpus callosum is divided so the two parts of the brain can't speak to one another and before the operation obviously draws a very good cue with the right hand that's information has come from the left hemisphere because when it's cut off look what it does it's not a race of flat representation so there's something that's happened there to the three-dimensional nature of reality now I haven't got time to go into all these differences and I haven't got time to talk unfortunately about the asymmetries of the brain and there was a long long chapter in my book in which I talk about all the evidence that I've gathered about the way it affects our the asymmetry is between the hemispheres give us different takes on the world and the newness of the right hemisphere makes it a devil's advocate is always on the lookout for things that might be different from our expectations it sees things in context it understands implicit meaning metaphor body language emotional expression in the face it deals with an embodied world in which we stand embodied in relation to a world that is concrete it understands individuals not just categories it actually has a disposition for the living rather than the mechanical and and this is so marked that even in the left-hander who is actually using their right hemisphere in daily life to manipulate tools with their left hand it is their left hemisphere not their right hemisphere in which tools and machines are coded so this is very interesting and it changes the view of the body the body becomes an assemblage of parts in the left hemisphere there's a different emotional tone bro I wish I had time to talk about it as about how it effects our understanding of music time and the self if I had to sum it all up I would I would get away from all those things that we used to say reason and imagination let me make it very clear for imagination you need both hemispheres let me make it very clear for reason you need both hemispheres to do a kind of very schematic rationalistic processing like a computer would you can use your left hemisphere but to reason fully you need both hemispheres and a lot of mathematical thinking and deduction is done in the right hemisphere so if I had to sum it up I'd say the world of the left hemisphere dependent on denotative language and abstraction yields clarity and power to manipulate things that are known fixed static isolated decontextualized explained it disembodied general in nature but ultimately lifeless the right hemisphere by contrast yields a world of individual changing evolving interconnected implicit incarnate living beings within the context of the lived world but in the nature of things never fully graspable never perfectly known as we think and to this world it exists in a certain relationship rather than just an objectives starts the knowledge is mediated by the left hemispheres however within a closed system it has the advantage of perfection but the perfection is bought ultimately the price of emptiness of self reference it can mediate knowledge only in terms of the mechanical arrangement of other things it already knows now I would have liked to have time to read some extracts perhaps I do from this book just to show you that actually what I'm talking about is not as abstract as it sounds if you if we don't think about mechanism first you know when somebody is right hemispheres not working they start to that their world on the left is just produced by the left hemisphere it's no longer produced by the right hemisphere this had a stroke there's a description here of a patient by Aaron vote where the left half of his chest abdomen and stomach should be he's got only a wooden plank it goes right down to his anus and is divided into compartments by transverse planks food doesn't follow the usual path from the stomach through the intestines it quote gets sucked into the compartments of this scaffolding and it falls through the hole at the bottom of the framework all this is only on the left side so this is very interesting and if you think about this virtuality tokens for things I really would like to read you this short extract about a patient so series of patients this was research done by very prominent neuroscientist or Marcel Ginsberg and a Russian colleague called Eglin when they looked at and how people reasoned on they gave them false syllogisms and that means one of the premises is wrong what deduction do you draw so major premise all monkeys climb trees minor premise the porcupine is a monkey which clearly it isn't implied conclusion the porcupine climbs cheese well does it Davis demonstrated each hemisphere has its own way of approaching this question that the outset of the experiment when the intact individual is asked does the porcupine climb trees she replies using of course both hemispheres it doesn't climb the porcupine runs on the ground it's prickly it's not a monkey during experimental temporary hemisphere in activations the left hemisphere of the very same individual with the right hemisphere knocked out replies that the conclusion is true the porcupine climbs trees since it's a monkey when the experimenter asks but is the porcupine a monkey she replies she knows it's not when the syllogism is presented again however she's a little nonplussed but replies in the affirmative since that's what's written on the card when the right hemisphere of the same individual is asked if the syllogism is true she replies how can it climb trees is not a monkey is wrong here so there's that and there's another very important thing about less there's a huge optimist and it indulges in the degree of denial so great is this denial this is a neurological fact it's not just an opinion I have about the left hemisphere if somebody had a stroke involving the left-hand side of the body their right hemisphere not operating because it doesn't fit with the left hemispheres idea itself that there could be anything wrong with it you will deny there's a problem it's not paralyzed at all we'll move it then and they no movement will happen but the patient will insist that they've just moved their arm I just wanted to read you this little extract so an examiner talking to a patient whose arm is this that's pointing to the paralyzed arm it's not mine whose is it it's my mother's how on earth does it happen to be here I don't know I found it in my bed and so so on and then when the hemispheres are when there's a procedure whereby you can temporarily activate the right hemisphere she goes back to completely accepting that she got a paralyzed on but once that wears off she goes back to its my mother's nothing to do with me guff so there's something there which is really extraordinary happening which you can actually see happily which is about denial now I'm going to be very quick now and just talk about the broader implications of what I've just said to you there's a problem here about the nature of the two worlds they offer us two versions of the world and obviously we combine them in different ways all the time we need to rely on certain things to manipulate the world but for a broad understanding of it we need to use the knowledge that comes from the right hemisphere and it's my suggestion to you that in the history of Western culture and I deal with this in the second half of the book in Greek culture in Roman culture and indeed in our own culture since the Renaissance things started in the sixth century BC in the Augustine era and in the fifteen sixteenth century in Europe with a wonderful balancing of these hemispheres but in each case it drifted further to the left hemispheres point of view and the Enlightenment was specialized in separating the head from the body in fact the French Revolution developed a special technique for doing this and and I would I'd like to bring to your attention is Berlin's famous and characterization of this Western way of thinking he said there were three things which applied in our view to all knowledge all questions can be answered anyone who's lived knows that can't be right all answers can be transmitted to others they can't they're not information that we can be fed in like into a computer you need to draw it out of someone else who has to already have it in them and all answers are compatible if I only so when you come a little bit later to Blake I've put this up because it shows the picture of the spirit of Milton entering his body through his as he says through the left our sirs going direct inspiration to his his right hemisphere in fact in an area near the limbic system which is the part that serves emotional understanding Blake knew that opposites innocent and innocence and experience and share something of one another nowadays we live in a world which is paradoxical it's very frustrating we pursue happiness and it leads to resentment and it leads to unhappiness and it leaves in fact explosion of Mental Illness that is the world we now live in we've pursued freedom but we now live in a world which is more monitored by CCTV cameras and in which our daily lives are more subjected to what de Tocqueville called a network of small complicated rules that cover the surface of life and strangle freedom more information we have it in spades but we get less and less able to use it to understand it to be wise there's a paradoxical relationship as I know as a psychiatrist between adversity and fulfillment between restraint and freedom between the knowledge of the part and wisdom about the whole it's the Machine model again that is supposed to answer everything but it doesn't think about this even rationality is grounded in a leap of intuition there is no way you can rationally prove the rationality is a good way to look at the world we Intuit that it is very helpful and logic ethics and aesthetics are all of this quality we say that they're made up out of bits that we've now worked out it's a utility thing beauty and morality but as Vicki and Stein wisely pointed out all these areas are transcendental we have to make a leap of intuition to understand them and this is not new at the other end of the process rationality we know from girdle's theorem we know from what Pascal was saying hundreds of years before girdle at the endpoint of rationality is to demonstrate the limits to rationality there are paradoxes in logic views of the great things in the Greek world that came into prominence about the time that we started to use the left hemisphere more at the end of the of that period so reality is not linear it's curvilinear and there is a conjunction of opposites that we use to understand in our modern world we've developed something that looks awfully like the left hemispheres world we prioritize the virtual over the real the technical becomes important bureaucracy flourishes the picture however is fragmented there's a loss of uniqueness the howlers become subsumed in what and the need for control leads to a paranoia in society that we need to govern and control everything everything that should be implicit becomes expert and the life is drained why this shift I think there are three reasons very quickly one is the left hemispheres talk is very convincing because it shaved everything that it doesn't find fits with its model off and cut it out so this particular model is entirely self consistent largely because it's made itself so and it's therefore very compelling I also call the left hemisphere the Berlusconi of the brain became because it controls the media is the one with which we it's very vocal on its own behalf the right hemisphere doesn't have a voice and it can't construct these same arguments and I also think rather more importantly there's a sort of Hall of Mirrors effect the more we get trapped into this the more we undercut and ionize things that might have led us out of it and we just get reflected back into more of what we know about what we know about what we know so I mentioned obliquely ro Donald Rumsfeld earlier dreadful man but a brilliant philosopher it's not that it's not the things that you know you don't know that bring you down in life it's those unknown unknowns and I just want to make it clear I'm not against whatever it is the left hemisphere has to offer nobody could be more passionate in an age in which we neglect reason and we neglect careful use of language nobody could be more passionate than myself about language and about reason it's just that I'm even more passionate about the right hemisphere and the need to return what that knows to a broader context so it's that business about the emissary going back to the master not usurping the master and when I'd finished this book I came across a quote from Einstein that I wish I'd known when I was writing it cuz it turned out that Einsteins thinking somehow presaged this thing about the structure of the brain he said the intuitive mind is a sacred gift and the rational mind is a faithful servant we have created a society that honors the servant but has forgotten the gift thank you [Applause] thank you very much inverse slightly behind schedule so I'm just gonna ask you one question although it may have more than one part so we'll see how that goes and you I actually managed to read the very long chapter you mentioned about the brain because I've run the social brain project I'm supposed to understand this stuff but I find it very very difficult and I very much enjoyed it but it's full of caveats qualifications it's very much not left brain bad right brain good it's replete with lots of sophisticated nuances and insights and evidence everything is very carefully referenced and documented so what I want to ask you is about the responsibility of the site that you have towards this idea because now you're sending out into the world and for those who are armed with your book and who can revisit this RSA talk they may feel safe that they won't make these mistakes and make sort of simplifications and distortions of what you're arguing this is such a powerful idea of human nature in human culture that is very important that it's protected and that the idea is not sort of polluted or adulterated in various ways which is almost inevitable to happen as it's you know left out into the world and people start talking about it so what I want to ask you with a quick a quick parallel offend me which is on Howard Gardner's theory of multiple intelligences he had a theory of bodily kinesthetic intelligence and once he went to visit a school where they said look we're doing bodily kinesthetic intelligence and he said that's my body listen kinesthetic intelligence that's just kids running around on the floor so what I want to ask you is how do you guard this idea how do you ensure that the power and beauty of it is kept sort of safe as you know as it unfolds well that's a very good question and I'm very concerned I mean I found that when I go out to dinner with somebody they tell me that they know their parking was screwed up because of their left hemisphere or their right over and I don't altogether welcome this I think I don't want to become the man who has a left hemisphere or right hemisphere take on everything and I want to emphasize what you said that this is a nuanced argument and it's not about bad and good and I do think it is difficult the thing is one can't guard against people misunderstanding it but I suppose what I fought is plenty of flags in there about it and I've tried to as you say give plenty of evidence as a two and a half thousand papers referred to there so you know people can go and look up what I'm saying and and and I'm perfect a bit of the discussion with anybody who can tell me you know where I've gone wrong so I think we just have to be careful about this but I know it will be it will be inevitably and sort of dumbed down in in a way and I don't know quite what I can do about that you

Channel: RSA

Views: 104,892

Keywords: Iain McGilchrist, the divided brain, brain, science, human behaviour, human behavior, society, culture, psychiatrist, the rsa, rsa, royal society of arts, left brain, right brain

Id: SbUHxC4wiWk

Length: 32min 11sec (1931 seconds)

Published: Mon Nov 22 2010