Instant Genius - Brain myths with Dr Lisa Feldman-Barrett

Episode Date: November 15, 2021

Lisa debunks some common misconceptions about the brain and explains how our grey matter really works. Once you’ve mastered the basics with Instant Genius, dive deeper with Instant Genius Extra, where you’ll find longer, richer discussions about the most exciting ideas in the world of science and technology. Only available on Apple Podcasts. Produced by the team behind BBC Science Focus Magazine. Visit our website: sciencefocus.com Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

This podcast is sponsored by name, audio and focal. Streaming has made music more accessible than ever, but true listening is about more than ease. It's about quality. British audio experts name audio, alongside French acoustic specialist focal, combine handcrafted tradition with cutting-edge innovation and high-end materials,

delivering digital precision with analogue warmth. So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com. to learn more. Hello and welcome to Instant Genius, a bite-sized masterclass in podcast form. I'm Daniel Bennett, the editor of BBC Science Focus magazine, and in this episode I'm joined by Dr. Lisa Feldman Barrett,

a neuroscientist whose research is shaking up conventional wisdom in the world of psychology. Lisa is a professor of psychology at Northeastern University, and she's the author of two brilliant books, how emotions are made, and seven and a half lessons about the brain, which has recently just been released in paperback for. Today, Lisa's joined us to talk about her work and her take on some of the common misconceptions we have about the brain. To begin with, I start off with something we probably all think is true,

and that's that the brain is built primarily for thought or for thinking, but Lisa's got a different perspective. No, it's really not the case. You know, when I started to think about, writing this book, I asked myself, why do we even have a brain? You know, brain is very expensive. So that three-pound blob of meat between your ears costs about 20% of your metabolic budget. So it's the most expensive organ you have in your entire body. And I thought, well, why did brains evolve? Like, they're very, very expensive. And you can't really say why anything evolved. I mean, you can

make up stories and you can make educated guesses. But you can say, you can look at the record, the evolutionary record, the developmental record, and you can say, okay, well, what is an organ's most important job? What is its main function? And when you look at the evolution of the brain, it's really pretty clear that the brain's most important job is not thinking and it's not feeling and it's not even seeing. It's running the systems of your body to keep you alive and well so that you can do your most important job from, you know, evolution standpoint, which is to pass your genes on to the next generation and help that generation survive to reproductive age. And so why was that where you started? And why is that important, I suppose,

because it does feel like everything then, I suppose, pulls out from that idea that actually the brain isn't, you know, solely built for thought. Well, first of all, I think it cautions us to have a bit of humility and be a little more humble than we usually are as humans, right? So we, you know, we think of ourselves. I mean, throughout the course of scientific history, we've thought about ourselves as the pinnacle of evolution.

and clearly that's not the case, meaning I'm not even actually making a snide remark, a cheeky remark about politicians or what have you. I'm just saying that evolution doesn't aim itself at any particular function or any particular type of animal. We are very well adapted to our environment, to our niche, as it's called, and so are other animals very well adapted to their niches. So I think it teaches us to be humble, but more important, I think it teaches us to ask very, very different questions than we're normally asking. And so here's one example. The comorbidity rate, the frequency with which heart disease occurs with depression is very, very high. In the United States, the estimates are about 70 percent. And I don't know what the worldwide estimates are,

but I wouldn't be surprised if they're similar. And scientists and physicians ask themselves, you know, what is it about heart disease that leads people to be vulnerable to depression? Or What is it about depression that leads people to be vulnerable to heart disease? When we look at the function of the brain, the brain's main function, which tells us something about its structure, how to understand its structure and the way that it works, we realize both those questions are completely wrong. Because heart disease is fundamentally a metabolic illness, and so is depression. So I'm not reducing everything to your metabolism, but I'm telling you this is a really important

factor that is overlooked. Serotonin, for example, which is a chemical in the brain, which is there is imbalance in this chemical in depression. People think about this chemical as the happiness chemical, but it actually functions as a metabolic regulator in your brain and your body, and it evolved for that purpose. It evolved as a same thing with dopamine. It's not a reward. chemical. It's a chemical that helps you to expend effort in the service of obtaining a reward or really engaging in any behavior that will cause you to spend a lot of energy, a lot of glucose and oxygen and so on. So the question, asking the right questions about illness and health really require that we understand how brains work.

And our own experience of the world and ourselves in the world is not always the best guide to understanding what's happening under the hood. So, I mean, on the one hand, there's obviously saying that we're just sort of machines for self-regulation doesn't necessarily chime in with my own experience of existence, I suppose. But also, I studied psychology actually at undergrad, and what I've loved about your books is how much of a sort of change in perspective that you kind of get across is perhaps needed across psychology. And just for those of us who perhaps haven't studied psychology, you know, that's not actually what necessarily we've been, how we've described the brain in the last sort of decade or even longer.

When we go to university, we learn about different. sections of the brain and how they govern us. And actually, the brain is very separate to the body. Yeah. So all of these things are very, very debatable, I would say. And I will say that, you know, like you, I don't experience every hug I give, every insult I bear as having anything to do with my metabolism or my energy regulation. But that's, but, you know, your own experience is, not a great guide to how the brain works. I mean, the brain is a bit of a master of deception because our brains create our experiences and guide our actions with such stealth and actually trick us into believing that the products of its efforts really reveal its functions and it,

but it doesn't. And so, for example, the idea that you have one part of your brain for thinking in another part of your brain for feeling and that the two are locked in mortal combat, your brain is battleground between rationality and emotion. And if rationality prevails, you're a moral person and you're healthy. And if emotionality prevails, it's either because you didn't try hard enough, i.e. you're not moral. Or you can't. Your emotions are too intense to control the animalistic part of yourself, too intense to control. And therefore, you must be mentally ill or, you know, have illness in some way. And this is a, this is a morality tale that's been with us since Plato, and it's embedded in many of institutions of Western culture,

like the law. And, you know, the law in the U.S. and also the law in the U.K. are really founded on some of these ideas. But they have no reality in the structure and function of the brain. it's not really possible anatomically for you to be free of feeling. If you are free of feeling, and here I'm using the word feeling is separate from the word emotion because they're not necessarily, they don't mean the same thing. If you are free of feeling, then something's wrong with your brain. And is that changing now in psychology, I wonder, since I read your first book, which talks about how we understand how the brain creates emotion,

and that for the most part, we've thought of the brain as this very separate entity to our bodies. It's just in this closed-off area and it doesn't interact. And actually your perspective on how we look at the brain and understand our minds is to actually have a much more holistic view of how the brain works with the body. Is that changing in psychology now? You know, when you're at the eye of a storm, it's really hard to know what the full magnitude of the storm looks like. It's really hard for me to answer that question. What I want to say is that I think there are pockets of psychology which have been saying

similar things the whole time. And even if we go back as far as William James, you know, who is the one that considered to be one of the founders of American psychology, you could even go look at Wilhelm Vund, some of his earlier writings, which is, he's one of the founders of European psychology. Some of these ideas are lurking in those writings, actually. I mean, James and Vant also, I think, really advocated for a holistic approach and really questioned folk psychology categories like memory, perception, you know, rationality, you know, cognition, emotion, really questioned whether these were the categories that really represent the functions of the brain.

So clearly the brain is producing these events, but that doesn't necessarily mean the brain is organized with little territories for each ability. And even somebody who has written about territories in the cerebral cortex, Broadman, this neuroscientist named Broadman, made it really clear that he was talking about architectural arrangements of cells,

and he didn't really think that each of these little island that you could distinguish in terms of their structure, the way that neurons are talking to each other, had anything to do with function. So I mean, so I'm not saying that, you know, your cerebral cortex doesn't have a function and that your hippocampus and like all the parts don't have functions. They do. But those functions tend to be what we would call domain general in psychology, meaning whatever

they're doing, they're doing no matter whether the event that's being created is an emotion, or a thought or an action or a perception or and so on that that these are it's a little bit like you know if you have flour water and salt you know you can do a lot with that you can make a lot of different things with that including some things that aren't even food you know like glue for example so the idea is is a little bit the same and I would say you know there's always going to be pushback There's always going to be pushback. Being wrong is part of science, but you're not rewarded for being wrong. Some scientists have spent their entire lives, entire careers invested in a particular way of seeing

things, and not everybody has the fortitude to realize when they're wrong. And I actually think, you know, we should be rewarding scientists when they, because being wrong doesn't mean that you haven't contributed to the process of science. So this is something I think the public doesn't necessarily understand that when the media sometimes reports being, you know, when there's a course correction, the media sometimes reports it as kind of like a gotcha moment. But actually being wrong is an opportunity for discovery and it requires a certain degree of bravery. And I've been wrong at times and had to admit it. And I've worked with colleagues who've been wrong and have had to admit it in print, you know. and we congratulate each other and support each other.

So do I think things are changing? I hope things are changing. But if you look at introductory psychology textbooks, many of the things that are printed in those textbooks, we know are not true anymore. I mean, we now know that are not true. And that was really the topic of my first book, how motions are made.

I sometimes wrestle with my own knowledge in that I just have these things I've learned from my undergrad degree that are just rooted in there, And sometimes they read something later. Me too. Me too. I have to say, I mean, when I was going to school, I learned that each emotion category of a select few in English have universal expression. That's not true. I learned that different types of memory have different locations in the brain. So when you have a general memory versus a very specific memory that's very specific to you at a specific time and place, that's not true.

And so it's very hard actually to remind yourself again and again and again that there's a different and better, scientifically more valid way of seeing things. And that's what you have to be using. Because you do tend to fall back on these old habits. But you can train yourself not to. It just requires, you know, it's like it's an investment of effort, like an exercise is. So then I just want to just highlight then and drill a little deeper in that idea. So we sort of learn. and here all throughout history about brains having these very distinct regions or divisions, whether it's Plato and his different three regions or Freud or whoever. But you see it a different way. And so if it isn't that kind of very clearly mapped out thing, how do you see the brain as structured?

Well, let me just point out that Plato was really writing about the psyche, which is loose. but not really, not completely translated as the mind. So, you know, for all of you philosophers and historians out there, I know that they're not equivalent, but for today's purposes, we can treat them as equivalent. I think Freud made gestures to neurology, but he really was talking about the mind. And Freud's view of the mind is very similar to Plato's view. And what happened really in the 20th century, or one way to think about what happened in the 20th century is that neuroscientists took this theory of the mind,

which is very old and is very rooted in morality, you know, which is a requirement for humans living together in groups, which is our major adaptive advantage. So it's an important thing. But they took it and they sort of tattooed it onto the brain and said, ah, well, you know, we can see with our naked eye. We can see that there's a part of the brain which we share with lizards, the so-called lizard brain, right? That is for instincts. And sometimes, you know, they'll tell a funny, like this is like a classic scientist joke. Like, the first. four Fs. The four F's, circuitry for the four Fs, fleeing, fighting, feeding, and copulation. That's a neuroscience joke. So the four Fs. And then along, you know, eventually mammals evolve,

and they evolve this layer on top, which is called the limbic system, limbic literally meaning boundary or layer, which is where emotion, the circuitry for emotions live. And then, you know, we get to primates and particularly us and we see the evolution of this very new cerebral cortex and, you know, referred to as the neocortex. And that's a story. The problem is it's a story that doesn't match the evidentiary record in molecular genetics and in embryology. So when you look at, when you peer into deep into cells and you look at their molecular structure and particularly the structure of the genetic material that is regulating the cells function. And you look at the setup of the nervous system of the brain in an embryo.

This is not, you don't see anything which looks like a brain that evolves in three layers. You know, the only animal on the planet who has a lizard brain is a lizard. You see quite, and this is a point you make very well, throughout evolution and through the animals today, we see actually very similar brains if you just look at it in a certain light. Yeah. So this, and I should say, you know, I'm very data driven, even as a, I mean, almost to a fault. I mean, if you talk to my husband or my daughter, they will, they could regale you with stories of how irritating it is to have, you know, a family member who's very data driven. But I'm very data driven. And, you know, these are not my data. I didn't

collect these data, the observation, which I think is a brilliant observation, that the structure of the brain, that all mammalian brains and perhaps even all vertebrae brains have the same types of cells with the same genes and the same. And there are some small differences here and there, but generally speaking, at least for mammals, all mammals have the same parts. what's different is that these parts develop in a specific order that holds for all mammalian species that have ever been studied. And what varies is the duration of each stage of development. And the longer a stage runs, the more of that particular type of neuron or that particular type of tissue is produced. And brains are kind of like companies as they get larger, they reorganize themselves to become more

and more and more efficient. That's a phrase from the neurobiologist George Streeter. And the work that I'm referring to about the developmental plan and that, you know, what's really happening here is that the timing of the turning on and off of genes is what's changing in evolution. And that's producing changes in the amount of tissue, certain types of tissue, certain types of neurons, certain types of materials that are being produced during the setup of the nervous system in an embryo. And that's what makes our brains look so different, you know, from a rat brain or from a lizard brain or from a bird brain. But the actual complement of neurons, the actual complement of tissue is not different. That work comes from my colleague, Barb Finley, who is a neuroscientist

and who, you know, really brilliantly looked beyond what she could see with the naked eye. And she also, you know, does something which I think more psychologists are now turning to, which is to take a more comparative approach across species and not look to other species to try to understand humans. But to try to understand species in their own terms, what abilities do they have for their own needs? What is the brain doing their brain's capacities for their own lives, these animals? And that is a better way of understanding what we can learn about other animals that we can generalize to ourselves than looking at a mouse as a really inferior like human. Yeah, as if they just lack a human brain for one.

Right, exactly. They just lack a big cortex. And so, you know, right, exactly. We were just the mouse that were smarter and bigger. Right, right, right, exactly. So then I just also want to look back to the idea of the brain and as this kind of this piece of equipment that maintains everything, particularly in terms of, you know, your core need.

So what's your heart doing? What are your lungs doing? And intake because you have this great analogy of it as a budgeting machine, which I kind of would love to talk about. And so can you just explain that for us? Sure, absolutely. So you have a lot going on inside your body. So do I. So to all of our listeners. So right now, as we're talking, you and I are talking to each other and our listeners are listening. Each of us has inside our bodies a whole drama going on with dozens of systems that have to be coordinated in the most metabolically efficient way. Because metabolic efficiency, like frugal spending is a major selection pressure on, evolution, but it's also a major pressure on adaptation of any individual. If you're, you know,

junk inside your body isn't working with, you know, in the most efficient way, you're going to pay a price for that. And that price is illness. And it could be a mental illness. It could be a physical illness, but eventually that's what's going to happen. So there's a lot going on inside our bodies and something has to coordinate those systems. Now, there are, you know, intrinsic mechanisms in your body that can do a little bit of that coordination. But the more complicated a body is, the more necessary it is to have a command center, which is your brain. There are technical ways to talk about this, about what the brain is doing and what its functions are in terms of regulating the body. But I find that the metaphor of a budget, running a budget, is a good one. Now, you know, the caution

here, right, is that metaphors are always Faustian bargains. Every metaphor is wrong in some way. The question is, how wrong is it? And so I think budgeting, you know, it has some issues. It's not a perfect metaphor, but it's a pretty good one. And the idea is that your brain is running a budget for your body. And it's not budgeting, you know, money. It's budgeting resources that are necessary for you to stay alive and that are limited, like oxygen and glucose and salt and water and so on.

And you can think about the things that you do, or the things that are going on in your body as deposits or withdrawals. So exercise, for example, big withdrawal. But it's like an investment because when you pay back what you've spent, you actually are investing in a stronger, healthier you with a better memory. Get a return. Yeah, exactly. When you give someone a hug, you know, or you're very supportive to someone,

that's also like an investment because we're social. animals. And we don't just make deposits and withdrawals in our own body budgets. We metaphorically make deposits and withdrawals in other people's body budgets, too, and they return the favor. We're social species. We're caretakers of each other's nervous systems. And that's a major aspect of how our brains function, actually. And so you can think about, you know, rewards are deposits, essentially. Well, because you have a great example. If, you know, at first, the idea of a budget might sound a little bit alien to your experience,

but then you do have some really good examples. For instance, with mental health and PTSD, you can see it in that perspective. Yeah, so in both books that I've written, how motions are made and seven and a half lessons about the brain, I'm using this metaphor of body budgeting. And so, for example, you know, cortisol. is not a stress hormone. Cortisol is a hormone that your brain directs your body to secrete when your brain believes that you have a big metabolic outlay coming, meaning you're going to spend a lot and you need to get glucose into your bloodstream really fast so that your cells

can use it really fast because you either have to learn something new or you have to move your body. And so why is there this mistake about cortisol being called a stress hormone? Because all stress meet. All stress is. is, is your brain preparing your body for a big metabolic outlay? And some stress is good stress, like it's stress that makes you healthy and strong, like exercise. Exercise is considered a good stressor. There are other stressors which are considered bad stressors, meaning they don't contribute. They're not really investments. They don't contribute to a stronger, better you. They're like taxes that you pay needlessly, actually. So unlike taxes, you know, in countries,

which, you know, are often used, but not always used in the best way, these metabolic taxes are completely and utterly useless. All they do is contribute over the long term to illness. Also, the most metabolically efficient way to run a body is predictively. So it's not like your brain is seeing and hearing stuff in the world and then reacting to that stuff. Your brain is actually always guessing, using your past experience and making similarity comparisons. Your brain is sort of metaphorically asking itself, well, in the past, what was similar to what was similar to what's going on right now? What did I do last time? Okay, that's what I'm going to do this time. And so it's actually anticipating and preparing in advance. And so, because that's what's most

efficient to do. A good, someone who's good with their budget sort of predicts the future. You know, they look at what's coming up in the future and prepares. All neurotypical brains predict the future. It's just some predictions are a little more efficient than others. And, you know, the analogies that work really, that are really fun, actually, to explain how this works are things like baseball or, you know, soccer, which is, you know, you would call football or American football. You know, these games where really what's going on, it's a battle of wits. It's, you know, because all the brains are predicting and they're all trying to outsmarty. other and that's really what's happening in these games, right? That's part of the skill of

these games. The thing is that when your brain predicts that a big metabolic outlay is coming, so it's a stress, you're experiencing a stress, and there is no need for that metabolic outlay. Over time, you know, each time this happens, you pay a little tax, and over time those taxes add up to a deficit. And when you're running a deficit in your body budget, you feel it as fatigue or as distress or as an inability to concentrate. And that, if it continues, will lead to depression. I mean, depression you can think about as a complete bankruptcy. That was Dr. Lisa Feldman Barrett there discussing the idea of a brain budget.

And the consequences to your health when that budget runs out. If you'd like to hear Lisa and I dig a little deeper into the subject of the brain, discuss the subject of free will, and explain how our brains are wired into one another. Check out Instant Genius Extra, a bonus podcast available via subscription on Apple's podcast app. And of course, if you want to learn more about the brain, check out Lisa's book, Seven and a Half Lessons About the Brain, which is on sale now and published by Picador. Thank you for listening. podcast is brought to you by the team behind BBC Science Focus magazine, which you can find on sale

in supermarkets and newsagents as well as your preferred app store. Alternatively, do come find us online at sciencefocus.com. See you next time. This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name Audio believes you can have digital precision. with analog warmth. Alongside French acoustic specialist focal, Name creates high-end audio systems, combining innovation with craftsmanship,

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