Renowned psychiatrist and writer Iain McGilchrist explains how our ‘divided brain’ has profoundly altered human behavior, culture and society. Watch RSAnimate video or McGilchrist’s Full Lecture here.
THE DIVISION of the brain is something neuroscientists don’t like to talk about anymore. It enjoyed sort of popularity in the 60s and 70s after the first split-brain operations and it let to sort of popularization which has since proofed to be entirely false. It is not true that one part of the brain does reason and the other does emotion; both are profoundly involved in both. It is not true that language resides only in the left hemisphere – it doesn’t; important aspects of it are in the right. It is not true that visual imagery is only in the right hemisphere; lots of it is in the left.
And so in a fit of despair people haven given up talking about it; but the problem really won’t go away. Because this organ which is all about making connection is profoundly divided. It’s there inside all of us, and it’s got more divided over the course of human evolution; so the ratio of the corpus callosom to the volume of the hemispheres has got smaller over evolution. And the plot thickens when you realize that one of the main, if not the main function of the corpus callosom is in fact to inhibit the other hemisphere.
So something very important is going on here about keeping things apart from one another; and not only that, the brain is profoundly a-symmetric. It is broader at the back on the left and broader on the right at the front; and slightly jacks forward and backward. And it is though as somebody got hold of the brain from underneath and had given it a sharp twist clockwise. 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 the trouble to expand some bits of one hemisphere and some bits of another, unless they were rather doing different things.
What are they doing? Well, it is not just we who have these divided brains – birds and animals have them as well. I think the simplest way to think of it is to imagine a bird trying to feed on a seed against the background of a grit of 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 a quite different kind of attention open; it’s got to be on the lookout for predators or for friends […] and for whatever else is going on. It seems that birds and animals quite reliably use their left hemisphere for this narrow focuses attention for something it already knows is of importance to it; and they keep their right hemisphere vigilant broadly for whatever what might without any commitment as to what that might be. And they also use their right hemisphere for making connections with the world: say, they approach their mates and bond with them, it’s more using the right hemisphere.
But then you come to the humans. And it true that actually in humans too this kind of attention is one of the big differences: The right hemisphere gives sustained, broad, open, vigilant, alertness; where the left hemisphere gives narrow, sharply focused attention to detail. And people who lose their right hemisphere have a pathological narrowing of the window of attention.
But humans are different. The big thing about humans is their frontal lobes. 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 always telling us we’re good at which is outwitting the other party, being Machiavellian; and that is 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 is always curiously missed out here is: it also enables us to emphasize for the first time because there is a necessary distance from the world. If you’re right up against it you just bite. But if you can stand back and see that the other individual is an individual like me who might have interests and values and feelings like mine, then you can make a bond. This is sort of necessary distance as 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 Erasmian. 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 hand for things and make tools; we also use that part of the language to grasp things as we say: it ‘pins’ them down. So when we already know something is 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 is no good if you’re fighting a campaign having all the information on all those plants and species that grow in the terrain of battle. What you need is to know specifics of where certain things are that matter to you and so you have a map and you have little flags. It is not reality but it works better.
The newness of the right hemisphere makes it the devil’s advocate; it 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 has a disposition for the living rather than the mechanical. And this is so marked that even in the lefthander 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 assembly of the parts in the left hemisphere.
If I had to sum it all up; I would get away from all those things that we used to say – reason and imagination. Let me make it clear: For imagination you need both hemispheres; let me make it very clear: For reason you need both hemispheres. So if I had to sum it up I’d say the world of the left hemisphere, dependent on denotative language and abstraction, it yields clarity and power to manipulate things that are known, fixed, static, isolated, decontextualized, explicit, general in nature, but ultimately lifeless.
The right hemisphere by contrast yields a world of individual, changing, evolving, interconnected, implicit, incarnate, living beings in the context of the lived world, but in the nature of things never fully graspable, never perfectly known. And to this the world exists in a certain relationship. That knowledge that is immediate by the left hemisphere is however within a closed system. It has the advantage of perfection but the perfection is bought out of it with the price of emptiness.
There is a problem here about the nature of the two worlds. There’s offered two versions of the world and obviously we combine them in different way 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 knowledge that comes from the right hemisphere. And it is my suggestion to you that in the history of Western culture things started in the 6th century BC in the Augustan era and in the 15th and 16th century in Europe with a wonderful balancing of these hemispheres; but in each case is drifted further to the left hemisphere’s point of view.
Nowadays we live in a world which is paradoxical. We pursue happiness and it leads to resentment, and it leads to unhappiness, and it leads in fact to an explosion of mental illness. We pursue freedom but today we live in a world which is more monitored by cctv cameras and in which our daily lives are more subjected to what [Alexis] de Tocqueville called a network of small complicated rules that cover the surface of life and strangle freedom. More information: we have it in spade; but we get less and less able to use it, to understand it, to be wise.
There is a paradoxical relationship as I know as a psychiatrist between adversity and fulfillment, between restraint and freedom, between the knowledge of the parts and wisdom about the whole. That 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 that rationality is a good way to look at the world; we intuit that it is very helpful. And it is not new: At the other end of the process, rationality we know from Gödel’s theorem, we know from what Pascal were saying hundreds of years before Gödel that the end point of rationality is to demonstrate the limits to rationality.
In our modern world we develop something that looks awfully like the left hemisphere’s world: we priorities the virtual over the real, the technical becomes important, bureaucracy flourishes – the picture however is fragmented. There is a lot of uniqueness. The ‘How’s” become consumed in the what, and the need for control leads to a paranoia in society that we need to govern and control and everything. Why this shift? I think there are three reasons: One is the left hemisphere’s talk is very convincing because it shaved everything that doesn’t find fit with its model off, and cut it out. So this particular model is entirely self-consistent largely because it made itself so.
I also call the left hemisphere the ‘Berlusconi of the brain’ because it controls the media. It is 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 is a sort of whole of mirrors effect: the more we get trapped into this, the more we undercut and ironize things that might have kept us out of it, and we just get reflected back into more of what we know about what we know about what we know…
And I just want to make it clear, I am not against whatever 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 I’m even more passionate about the right hemisphere and the need to return what that knows about a broader context.
It turned out that Einstein’s thinking somehow prejudged 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.
He is committed to the idea that the mind and brain can be understood only by seeing them in the broadest possible context, that of the whole of our physical and spiritual existence, and of the wider human culture in which they arise – the culture which helps to mould, and in turn is molded by, our minds and brains.
McGilchrist was a late entrant to medicine. After a scholarship to Winchester College, he was awarded a scholarship to New College, Oxford, where he read English. He won the Chancellor’s English Essay Prize and the Charles Oldham Shakespeare Prize in 1974 and graduated (with congratulated 1st Class Hons) in 1975 (MA 1979). He was awarded a Prize Fellowship of All Souls College, Oxford in 1975, teaching English literature and pursuing interests in philosophy and psychology between 1975 and 1982. He then went on to train in medicine, and during this period All Souls generously re-elected him to a further Fellowship (1984-1991), and again in 2002 (to 2004).