Transcript
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It's an odd thing that isn't often enough talked about that the brain which is only about making connections has a whopping great divide down the middle. I went through in my entire medical training without anybody raising the question. As soon as you think about it, you think, my God, that's very strange. And it does have this join at the base of the corpus callosum, but over the course of time, the corpus callosum has become more and more inhibitory in nature, which is a very odd thing. So there seems to be something going on here about separating things in the heavens. So what is it that need to be separated? And I think in brief, it's the necessity to solve a survival problem, which almost every creature has, except perhaps human beings living in the West now, which is how to eat and stay alive at the same time.
[00:58]
Because for most animals, whatever they may be, they have to do two competing things at one and the same time. They must pay a very narrowly focused, precise kind of attention to something that is at the moment the subject of interest, something that you can eat, something you can pick up to use, say like a bird picking up a twig to build a nest, something instrumental that we want to get hold of for our purposes. Without that, no organism is going to survive. But if that's all it's doing, it will make itself very, very vulnerable and will become someone else's lunch while it's getting its own because at this exact same time, it has to be maximally aware of everything else going on around it. In other words, it has to be looking out for predators. It has to be looking out for members of its species, for its family that it wants to avoid, wants to be close to.
[01:56]
What else is happening and changing that needs to be monitored all the time while rigidly focused on this tiny thing. Now that is actually impossible to do if you only have one way of paying attention. In fact, it's very hard, but you can be trained to do this. Yoga can train you how to do this. It's very hard for most people to be able to focus attention on something and still be completely open to everything that's going on in the periphery. But as I say, if it weren't that we had a divided brain, we couldn't do that hard as it is. So what I think animals had to do in order to survive was to be able to have one kind of attention, which is, as I say, committed and one that is absolutely uncommitted as to whatever it may find. It has to be sustained over time.
[02:48]
It has to be very broad in scope, exactly the opposite of the narrowly focused, instantaneously grasping attention. Now, this division of labor, if you like, is apparent in every living thing that we know. It's actually even there detectable in the fossils of trilobites, but it is there in ... I used to say it's there in mammals and reptiles, amphibians, and birds, but it's also there in the most ancient fish. It's there in the most ancient sea creatures. It's there even in tiny nematode worms. It's there in insects. It's there in everything that lives. Now, a lot of things follow from that because if you believe that attention changes what you find in the world, the world will change. That's the philosophical point.
[03:47]
Now you won't ... Oddly enough, what I'm saying has been considered controversial, but if it's decomposed into two parts, it's not controversial at all. For example, it is not a bit controversial that creatures that we know about use the two hemispheres of their brain or protobrain for different purposes. And it's not disputed that the majority of them will tend to prefer the left hemisphere for this narrow focus and the right hemisphere for this broad sustained attention. And it's not for a moment disputed that in human beings this is the case. So you wouldn't find a neurologist anywhere in the world who would tell you differently from what I'm now telling you, that the two hemispheres pay this different kind of attention. But you also wouldn't find a psychologist or philosopher who would say attention makes no difference to the experiential world. Of course, it makes a difference.
[04:47]
In fact, there are a number of fascinating clips, some of them are very funny that have gone viral on the internet to do with attention. For example, Darren Brown and any good magician is basically a master in manipulating attention so that people don't see and experience certain things at all.
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Okay. So we've spoken a bit about the ... Well, you could even say that it's perhaps a fundamental aspect of reality, this idea that there needs to be two modes of attention.
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Two modes of attention.
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But beyond that, it's then reflected and represented and embodied by the two hemispheres.
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That's right.
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And in addition, they need to be held apart.
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They need to be held apart. And here's a surprise. Until mammals, there was no effective connection. So the corpus callosum is not something ancient to this structure. This biparthite, asymmetric formation has been, depending on what you mean by a neural system, present for about 700 million years. But having a corpus callosum, callosum has only been present for about 200 million years, and only mammals have it. Reptiles don't, fish don't, birds don't, but they get bio, right, don't they? So there's something very odd about this idea that they have this connection, but actually don't use it very much. And to explain that in detail would be complicated, but I think I can sum it up by saying this, that when mammals first evolved, they were very small creatures compared with the dinosaurs that they were eventually going to replace, and they had to live very close to the ground, and they were probably nocturnal.
[06:33]
And in order to have all their senses on the alert, they needed to be able to fuse sensory information, tactile information from the fur, which is important for heat, but also important for feeling where you were close to the ground. Having all that information, including being able to track things across the visual field present at the same time. And as mammals evolved, they got more into the question of being very swift moving predators. And to do that, they needed to be able to integrate visual information across the whole field. And we think that that is why the corpus callosum evolved, because if you like having super fast broadband between the two hemispheres, it's white. White matter in the brain is white because the nerve cells are sheathed in a substance called myelina, fatty substance, which causes an enormous increase in the speed of transmission. Now, if you want a lot of transmission to go on very fast between the two hemispheres, you want thick nerves, because thick nerves transmit faster than thin ones, and you need myelinated ones because that makes them faster.
[07:46]
I've just explained that. And the trouble is that as the brain gets bigger and more information needs to be transferred, more and more of the brain would have to be taken up with thicker and thicker cables, if you like, connecting the two hemispheres. It can't be done. So at a certain point in evolution, we started to have to make trade offs. Okay, we only communicate the minimum information that is absolutely essential and those nerves remain large and myelinated and a lot of the rest has not exactly shrunk, but it just hasn't enlarged. So if you look at the cross-section of a brain of a dog, I can give you an illustration of that one, but you'll see that the corpse closer in relation to the size of the brain is much bigger than it is in a human being. So effectively, our brains have not kept up in communication terms.
[08:42]
It started with mammals and it's already receding as you get to human beings in importance. And what's more, most of its effect now is actually inhibitory. It started off being facilitatory. Let's give visual information from this field to that, but because of specialization, because of the need to communicate only the very most vital pieces of information, each hemisphere had to become a bit specialized. It's like two departments that decide we don't both need to work on this together. I'll do this, you do that, and we'll just communicate on a need-to-day basis.
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So then the need for specialization became more important or perceived to be more important than the need for communication.
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That's right. And if you specialize efficiently, then you only need to communicate results to the other hemisphere. You don't need to have this vast transfer of information. So inevitably, as the brain got more sophisticated, the two hemispheres became more differentiated.
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And of course the best collaboration occurs when there is specialization.
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Exactly.
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But at the same time, the worst collaboration occurs where it begins with specialization and then it becomes just one mode, two specializations and it becomes just one and the other is ignored.
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So it's finding the balance, minimal communication in order to make collaboration maximally effective. That means a lot of the time actually switching off what's going on in the other hemisphere in order not to confuse the picture, but also giving that hemisphere the important information that it needs to have.
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And that's largely the role of the- That
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Is the role of the corpus.
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The
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Corpus callosum. Some people are a little confused because a lot of the neurons that cross the corpus callosum, and they're only 2% of the brain that actually do cross, that's giving you something to work on, are excited to you, but they end on inhibitory neurons in the large majority of cases, so that ultimately their effect is inhibitory.
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Which brings us on to the frontal expansion, which is another key aspect of what makes us human, but also the argument within your book, The Master and His Emissary. Could you unpack and gloss what the frontal ... What do we mean by the frontal expansion and given we now are the tail end of the expansion, how does it affect the way we behave in the world?
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Well, interestingly, the frontal lobes are another mammalian invention. All non-mammals don't have frontal lobes, so why do we have frontal lapes? They have been an enormous enrichment. They add another ... They basically doubled the neuronal layers from three to six in the part of the cortex of a reptile, from being a reptile to being a mammal. So it gave an enormous amount of extra power to the brain. And this is probably, again, because in order to survive, these new mammals had to do a lot of things that reptiles didn't have to do. Reptiles moved slowly and were extremely large, but these creatures were very vulnerable. They had to maintain a body temperature at a certain level. They had to monitor their environment for predators and be quicker catching the food that they needed. So they had to be more astute, basically. And the frontal lobes enabled them to become more astute.
[12:43]
And as you look from simple creatures such as the Shuro or the mouse, up through the evolution of more complex animals, such as dogs, to monkeys, and then to the great apes, and finally to humans, you see the growth of the frontal lobes. And what have the frontal lobes ended up doing? Rather like the corpus corlosion, their role has probably changed and probably in the same way. So initially their role was to give more processing space, if you like to use the computer metaphor, which I don't, but there you are. It gave more room for things to be worked on in the brain. But over time, it has become more and more important for us to stand back from the world in order to see things better. Most animals live in a very stimulus response level, that if you do a certain thing, they will respond immediately in a certain way, because that's good for survival.
[13:51]
But for us and for higher, as we call it, not my word, mammals, it's very important to be able to stop yourself from doing this. For example, one of the reasons that we are both, it works both ways, so social is that we're intelligent and so intelligent because we're social. Our social being is as important to us as anything. Aristotle called us Zoan political, which doesn't mean the political animal. It means the social animal because it comes from the word police, which means a city or a community. So that part of us means we've got to inhibit certain reactions. If you're going to be social, you've got to see ... I don't want to just keep biting and fighting off people. I need to actually form bonds with them and we can cooperate to greater ends. I mean, just as a brief aside, one that is staggeringly important is that we have been sold half a story by extremely prominent people whose names I don't even need to mention to you because they will be so obvious about the way that the biological world works, which is this ruthless story of competition.
[15:05]
That is half a story at best. Yes, there is competition, but more than anything, there is collaboration. Now, collaboration doesn't mean no competition, just as you were saying, for things to work well as a team, they need to be specialized and differentiated. So as we grew in sophistication, we needed more and more to be able to stand back from the world in space and time. In space, I mean, to be able not just to look at what's immediate, but to look at the whole picture and try and put the parts together and see a broader context. And in time, what I mean is not to see what will immediately happen, but what will happen two steps down the line. So for example, if I bite this creature, either I will frighten it off or kill it, okay? An immediate danger has been avoided, but if I instead adopt a more conciliative position, maybe I can form a bond with this creature and down the line, we can become better at doing what we both want to do and we can form a kind of bond.
[16:15]
So we have this frontal lobes in order to stop us doing things. It is largely inhibitory. It doesn't start a process. It monitors a process and says, "We've had enough of that now. We must stop it.
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" Is it involved in saying the right thing? For instance, when I was younger, I was fairly renowned for instantly saying the first thing that came into my mind, and I was entertaining in class, I should add, but I'm grateful that I'm now able to have something come into my mind and wait for a moment before it's released. Is that the frontal-
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That is definitely the frontal lobe.
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The only thing I would add is that it's a really difficult one because wit implies speed. And so if you want to be really witty, sometimes you just have to let it out instantly, but the risk you take is then offending someone.
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Yes, but actually calibrating those things is exactly the sort of thing the frontal lobes are good at. And I would say also that that particular thing of not saying things that will offend others is quite specifically right frontal, not left frontal. And for example, people who are on the autistic spectrum are not good at realizing that what they think is not what other people think or even want to hear necessarily. And those people have perfectly adequately functioning left frontal lobes, but something seems not to be working so well in what should be their social brain, which is most of us is their right hemisphere.
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It seems to be something though that can be nurtured because-
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It can be learned.
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Yeah. It can be nurtured too. But I mean, I only say myself because undoubtedly I'm a much more tactful person now than I was. And reading your book when you talk about things like lack of eye contact, reading the mouth instead of reading the eyes, these are things that I noticed in myself, but at the same time, having now done and pursued a more creative path, for want of a better word, where I've required more use of a way of being that seems to embody the right hemisphere, it's come hand in hand with being able to stand back from the world and have more tact.
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Well, that's right. So it is something that we all acquire actually with time and get better at until we start to get demented and then things pop out again. But that's because dementia is commonly accompanied by poor function in the frontal lobes.
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Also, I sometimes feel it's because, I mean, not necessarily true, but one reason why we need to be tactful is because we're social animals and if you're not tactful, then you offend people and you create distance. When people get older, they get a bit more relaxed about the idea of having to
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Be
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Connected to others so they're more loose with their words.
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It's true. A lot depends to coin a phrase on the how as much as the what. It seems to me that there are very few things that should not be sayable, but what they are should be said in a reasonable, not deliberately offensive manner. One of the problems that we now encounter is that we are increasingly entering a world in which probably one of the most restricted worlds of thought that there has been in the West, where whole areas are simply not allowed to be discussed. The whole vastly important topics that no person, if they want not to be labeled as some kind of hideous monster can even talk about, that these things should be talkable about. It's just that they should be talkable about it in a peaceful way. Once they start being talked about in an offensive way, on either side, then they're wrong.
[20:10]
And after all, if they're wrong, then they can easily be demonstrated in arguments to be wrong. If they're right, we need to listen to
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Them. Yeah. It's not just what is said, but how it is said. It's how it ... And we're all aware of how frustrating it can be that we're not able to have conversations that need to be had because people ... And I think this is related to how a lot of people feel that the position they've arrived at in the world with their worldview, it's their worldview that they've chosen rather than recognizing that we're sort of a moment in history and that the position, the take that we have on the world is partly ours and partly a function of what's come before.
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Yes. It's about 3% ours and about 97% something we've picked up.
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And I haven't been able to find the quote that Jordan Peterson mentions, and I really love this line. He goes that we don't have ideas. It's you, apparently, but I haven't managed to find it. We don't have ideas. Ideas have used us.
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Yes.
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And as soon as you start saying that, it then opens the door to a much more free speech because that you can be curious to know what ideas are holding other people.
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Yes. And it's been said by other people than you, you're quite right. I think somebody said complexes don't have us. That's young,
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That's young as well. We
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Don't have complexes, complexes of us, but also language. Heidigo says, "We don't speak in language, language speaks in us." All these things may sound a bit opaque at first listening to, but they embody important truth.