RSA Animate: The Divided Brain by Iain McGilchrist
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.
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.
It's there inside all of us, and it's got more divided over the course of human evolution, so that the ratio of the corpus collosum 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 collosum is in fact to inhibit -- is 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 asymmetric. It's broader at the back on the left, and broader on the right at the front, and sightly juts forward and backward. It's as though somebody had got hold of the brain from underneath and given it a sort of 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 trouble to expand some bits of one hemisphere and other bits of the other 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.
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 grit or 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; it's got to be on the lookout for predators, or for friends or con specifics, or 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. So they approach their mates, and bond with their mates, more using the right hemisphere.
But then you come to the humans. And it's true that actually in humans too 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 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 other party -- being Machiavellian. 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 always curiously missed out here is that it also enables us to empathize for the first time. Because there's a sort of necessary distance from the world; 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 Erasmian.
Now to do the Machiavellian stuff, to manipulate the world -- which is very important -- we need to be able to 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 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 terrain of battle. What you need is to know the specifics of where certain things are that matter to you. And so you have a map, and you have little flags. It's not reality but it works better.
The "newness" of the right hemisphere makes it a devil's advocate. It's 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 this is so marked that even in a 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.
If I had to sum it all up I would get away from all those things that we used to say. Let me make it very clear: for imagination you need both hemispheres. Let me make it very clear: for reason you need both hemispheres.
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, explicit, 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. And to this world it exists in a certain relationship.
The knowledge mediated by the left hemisphere is however within a closed system. It has the advantage of perfection but the perfection is bought ultimately at the price of emptiness.
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 knowledge that comes from the right hemisphere.
And it's my suggestion to you that in the history of Western culture things started in the 6th century BC, in the Augustine era, and in the 15-16th century in Europe, with a wonderful balancing of these hemispheres. But in each case it 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, to unhappiness, it leads in fact to an explosion of mental illness. 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 parts and wisdom about the whole.
It's 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 this is not new. At the other end of the process of rationality, we know from Goedel's theorem, we know from what Pascal was saying hundreds of years before Godel, that the end point of rationality is to demonstrate the limits to rationality.
In our modern world we've developed something that looks awfully like the left hemisphere's world. We prioritize the virtual over the real; the technical becomes important; bureaucracy flourishes.
The picture however is fragmented. There's a lot of uniqueness. The How has become subsumed in the What. And the need for control leads to a paranoia in society -- that we need to govern and control 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 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.
I also call the left hemisphere the Berlusconi of the brain because it controls the media -- 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 ironize 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.
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.
It turned out that Einstein's thinking somehow pressaged this thing about the structure of the brain. He said ([actually he didn't]) "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".