Kim Mills: When you're angry or do something impulsive, that's your reptilian brain in action, right? And if you talk yourself out of that impulsive act or gain control over your wrath, that's your neocortex at work, isn't it? And those emotions you feel, such as grief when a loved one dies or joy at the birth of a child, those are just things that happen to you in reaction to events in your life, correct? And they're universal across cultures, aren't they? Well, maybe not. What if emotions are things that our brain constructs to make sense of the signals it gets from our body and from the world around us. What if the way you think about your brain and how and why it functions is just plain wrong. Welcome to Speaking of Psychology, the flagship podcast of the American Psychological Association that examines the links between psychological science and everyday life. I'm Kim Mills.
Our guest today is Dr. Lisa Feldman Barrett, a distinguished professor of psychology at Northeastern University. Dr. Barrett has spent more than three decades studying emotion. Her research has helped to develop the idea that the human brain creates emotions by predicting rather than reacting to what happens in the world around us. She's published more than 240 scientific papers and is also a prolific science communicator, writing articles and books about brain science for the general public. Her two most recent books are How Emotions Are Made, published in 2017, and Seven and a Half Lessons About the Brain, which came out in November.
Thank you for joining us today, Dr. Barrett.
Lisa Feldman Barrett, PhD: Oh, it's a pleasure to be here, Kim.
Mills: I want to start with an idea that opens your new book, which is that the main purpose of the brain is not to think, but to regulate our bodies. This may seem counterintuitive or come as a surprise to some of our listeners. I'm wondering, can you explain how you came to this conclusion and why it's so important?
Barrett: I actually started with the question of why do we even have a brain. That blob of meat between your ears is the most expensive organ that you have in your whole body. And so why do we even have a brain? And so what I did was I went back in the literature and I looked in the literature on evolutionary neuroscience to a time when animals on the earth didn't have brains and looked at the evolution of the brain and found some really remarkable evidence that brains evolved under the selection pressure of predation. So during the Cambrian period, animals learned to hunt one another deliberately and eat each other. And it's not that animals didn't eat each other before then, but there was very little evidence of actual hunting. And so under the selection pressure of hunting, what happened is that bodies got bigger and required much more coordination of internal bodily systems, because animals without brains don't have very much going on inside.
They have some internal coordination, but not very much. And they really have no sophisticated senses to speak of–that is, they don't see, they don't hear, they don't smell. They really don't know very much about the world outside their own bodies. And what you see under predation is that bodies get bigger, senses evolve and brains appear. And if you look at the anatomy of the brain, what you see is that at the core of the brain, even at the core of the cerebral cortex, are the regions that are regulating the systems of your body, your immune system, your metabolism, endocrine system, your autonomic nervous system and your skeletal muscle system. And the networks in the brain that are responsible for remembering and thinking and seeing even are actually involved in regulating the body. And so the bottom line is that we do think, and we do feel and we do see. But we do those things in the service of regulating the systems of the body.
Now we don't experience every feeling of gratitude or sadness, every hug we give, every insult we bear as having anything to do with the body, but it does. And the reason why this is important is that many of the things that we think of as mental, illnesses like depression and anxiety, or even just things like seeing or thinking, actually have important aspects to them that are related to the body. So depression, for example, in addition to being a mental illness and having immune functioning problems is also a metabolic illness, actually. And that's why it's important that we understand, it really starts to break down the boundary between the mental and the physical. And so we can understand, for example, that all mental disorders actually have basic physical processes that are in disarray and also things we think of as physical illnesses, like cardiovascular disease and so on, actually have mental aspects to them, which are really important to understand.
Mills: So a few moments ago, you talked about the brain being the most expensive organ. What do you mean by that?
Barrett: Metabolically speaking, your brain costs you 20% of your metabolic budget. That's more than your heart. That's more than your lungs. That's more than your liver. It's a very expensive organ to keep running. All those little neurons and so on. It's really expensive, actually, metabolically speaking. And it turns out that metabolic efficiency is a major selection pressure, not just on any species that's alive, it's true. But also it's important for the evolution of any species. It's also important for your health, mental and physical. If you have metabolic dysregulation or things are not running as efficiently metabolically, and I'm not just talking about circulating glucose or something. That's one very small part of a very large complicated system. If your energy regulation is not proceeding in a metabolically efficient way, you will get sick.
Mills: And are our brains more expensive than other mammalian brains? I mean, we have this big hunk of meat up there.
Barrett: Yes, they are. Yes. When you look at primates, let's say relative to other mammals, primates do have bigger brains relative to their body size than other mammals do. And humans have bigger brains. But I would say that the size of the cerebral cortex is not any bigger than you would expect for a primate who has a brain of our size. So it's not like our cerebral cortex is so big relative to the rest of our brain. It's just we have a big brain relative to our body size. And our cerebral cortex is as big as you might expect for a creature who has a brain of our size, but there's some genetic upregulation in the human brain that makes it more expensive to run, in particular layers of the cerebral cortex that have to do with our ability to... so you could say compress information, summarize information from multiple sources so that we can do things like abstraction.
Mills: What might be a surprising point to some people in your book, I think I alluded to it a little bit in the introduction, is the way that many of us were taught about the brain is wrong. So a lot of our listeners for sure remember learning that there are three parts of the human brain. You've been asked this a million times. We think there's the lizard or reptilian brain that controls our basic bodily functions. There's the emotional brain and then there's the rational brain, the neocortex, that's the pinnacle of evolution and makes us supposedly superior to other animals. But you say this is incorrect. So where did the idea of a triune brain come from and how do we know that it's wrong?
Barrett: Okay. So I got to say, I'm happy to talk about it. I have been asked about this a lot, but I'm so happy to talk about it because it's one of the most pervasive modern myths in science. It's not even wrong, is what I would say, Kim. And I also have to say that this is not my research, right? I don't do research on this topic. Although I do research on brain organization and its relevance for psychological functioning. And I do research on the structure and function of tissue that is called limbic, but it's not called limbic because it's about emotion. It's really more about the anatomical structure of the tissue. But let me just say that the idea of a triune brain, a brain in three layers really can be... I've traced it all the way back to Plato.
Mills: Wow.
Barrett: Because Plato talked about the soul or the psyche, which is not exactly the same as a mind, but for present purposes, it's close enough. You talked about the human psyche is having three parts, one part for instinct, one part for emotion, which he representatives with beasts, right? Two horses, and then a charioteer, which is human rationality, which obviously controls the beast. And so right there, you have this idea of an inner beast and a rational part, and they're in constant battle for control of the chariot of your behavior. That's basically the idea.
And so fast forward, like a couple of thousand years, and we're in the era of modern neuroscience, like in the mid-20th century, and you have scientists using the best tools available to them, which is the naked eye or maybe some not so powerful microscopes with some dyes. And you look at a lizard brain. Now the lizard brain looks like it has a set of parts. And then you look at a small mammal brain like a rat and you're, oh look it looks like there's some extra parts there. And then you look at a human you're like, oh wow, definitely a really big extra part there. And so the idea that really grew out of this, that comes from Paul MacLean–who was a neuroscientist in Boston, actually, where I live–in the 1940s is this idea that lizards have circuitry for instincts. And then layered on top of that evolved the limbic system, limbic meaning border, which is really old cortex, considered to be old cortex that borders these lizard parts, which is where emotions live. And then layered on top of that is the new part of the cortex, the neocortex, which is where rationality lives, the pinnacle, as you say, of evolution.
And so there are a couple of things wrong with this view. One is that evolution, we aren't the pinnacle of anything. Evolution didn't aim itself at us, to use, paraphrase wording from Henry Gee the paleontologist. And animals are well adapted to their niche. If a species still is around, after a couple of hundred thousand years or longer, then it means it's well adapted to its niche. And other animals have some pretty miraculous abilities to do things that we don't have, frankly, and that we endow our superheroes with. So yes, it's true. We can do some pretty amazing things as humans, but other animals can do very amazing things like grow back limbs –
Mills: Yeah, we can't fly.
Barrett: Yeah. We can't fly. We can't grow back limbs. We definitely can't grow new neurons in most of our brains, whereas other animals, there are animals who can do all of those things or each of those things, right? But more importantly, the evidence from molecular genetics, when you peer in deep into the cells, the molecular structure of cells, and you look at the genes deep within, what you see is really clear evidence that brains did not evolve like sedimentary rock, or what I think of it as, you've got this deep animal beast, like inner ancient beast, and then what evolved on top of that was rationality like icing on an already baked cake.
Brains didn't evolve that way. They just didn't. That's the evidence. And the evidence has been around for more than 50 years and yet hasn't managed to percolate its way into, not just into the public sphere, but into psychology textbooks. Like, yeah, anytime you read that the amygdala and other parts of the limbic system, which I would put in scare quotes because there is no limbic system in your brain. Anytime you read that the amygdala or the limbic system is being regulated by the prefrontal cortex, that is a phrasing which rests on this old really mistaken idea that you have this inner beast lurking inside your brain, which is constantly in battle with your more sensible rational self.
And that the outcome of your–When your rational side wins, you're healthy and moral. And when your inner beast wins, you're either–If your inner beast wins because you didn't try hard enough, then you're not moral. And if your inner beast wins because there's something wrong, then you're sick. That's just a morality tale, but it doesn't reflect actually the biology of how we got these miraculous brains to begin with.
Mills: You make another really interesting point in your new book that I think is another myth busting point. I think a lot of people have the sense that parts of our brains go dormant from time to time when we're not using them. And I think what you're saying is neurons are firing all the time. Maybe you can explain a little bit about how that works and why.
Barrett: So if you look back in the history of how neurons were discovered and how they were studied, like in the 1950s, for example, one way to study the properties of a neuron was to take a big squid neuron, like literally take it out of the brain and lay it out on a table. And when you lay out a single neuron on a table then you can see, because these are really giant squids have very–they have a neuron that you can see with the naked eye, as I understand it–it's dormant. And then you have to stimulate it with electricity to get it to produce an action potential down at the axon. And this is very convenient and consistent with the idea that–the stimulus response idea that has really been around in psychology really since the inception of psychology, right?
So psychology as a field was a field of full mental philosophy until the mid-19th century when philosophers and neurologists and physiologists started to use the methods available to them from the physiology lab and from patients with lesions to try to search for the physical basis of the psychological categories that were in mental philosophy. So the physical basis of memory, the physical basis of emotion, the physical basis of perception and so on. And the idea was that, the brain is stimulated, the mind is stimulated by something in the world and then maybe some processing goes on inside. And then there's a response. So it's stimulus response jazzed up. This was very consistent with what happens when you look at an individual neuron, lying on a table, it's dormant and you have to stimulate it in order for it to fire.
But that is not how neurons work when they are actually in situ with other neurons bathed in chemicals and oxygen and so on. Neurons are constantly talking to each other. Your brain is basically having a conversation with itself throughout your entire life. And that's ongoing, and information from your body and information from the world merely modulate that ongoing activity. And that is the way the brain works. It's only to say, and therapists know this–they use different words, but it's exactly the same idea–that the brain is running a model of the world, an internal model of the world. That's not quite right. The brain is a model and it's a model of the body as it receives information from the world. So we don't model the world. We model the information that arrives to our sensory surfaces, like our retinas and our cochlea and so on and so forth. And all of the sensory services inside our body.
And the brain is receiving this information. And it's attempting to make sense of it so that it knows what to do next to keep itself alive and well. And it's using past experience to make these guesses. So what you see and what you hear and what you smell and what you taste and so on and what you feel in your body, because you don't really feel anything in your body, you feel everything in your brain, everything is felt in your brain. You see in your brain, you don't see in your eyes, you hear in your brain, you don't hear in your ears. Everything you experience and everything you do is a combination of what's in the world and in your body, because from your brain's perspective, that's outside the skull, right? So what's in the world, what's in the periphery. And what's in the past that your brain re-implements as the present.
Mills: Let's turn to your work on emotion, which is also fascinating. And one of the big ideas that you've developed is that emotions aren't things that happen to us, but they're something that our brain constructs. Explain that.
Barrett: Well, yeah.
Mills: In 25 words.
Barrett: So what goes along with this idea that we're born with these ancient circuits, right–buried deep inside our brain hardwired already–there is this idea that emotions happen to you. Something happens in the world, like you see a snake and it triggers fear. And then fear produces this whole cascade of events. You make a particular facial expression, your heart rate goes up, maybe you freeze or you run. And the idea is that this is universal with everybody in the world. And for everybody who has a neurotypical brain, who has these circuits, which are derived from ancient mammals or were involved in hunter-gatherer societies in Africa or whatever. There are different versions of it. And I'm painting a, you might want to say as a straw man sort of a description, but you can add bells and whistles and nuances.
But the basic idea is that emotions are universal. They have a single set, anger has a single set of features. Maybe it has some variation, but not so much variation that you can't recognize it in someone's face or in their body or in their body movements or in their voice or whatever. And all I can say is, I know it feels that way. It feels that way to me, too, when I get angry, when I feel gratitude or any rush of emotion to me feels exactly the same way as it feels to you. But that is not how the brain works. And that is not what the evidence shows. I mean, so the evidence shows really clearly, it couldn't be clearer, frankly, that emotions are not universal. What is universal however, is that the human brain is constantly constructing experience.
It's constantly trying to make sense of the world around and the body, or actually, I would say, it's trying to make sense of what's going on inside the body in relation to what's going on around us outside in the world. And it's doing this using past experience and it's always doing this. So the way I would say it is like this, the evidence to me suggests very strongly that your brain receives sense data from the world, sights and sounds and smells and so on. And it receives sense data from the body. And so when there's a loud bang or a tug in your chest, your brain receives that information as the outcomes of some set of causes. But what caused that loud bang? Is it a car backfiring? Is it somebody slamming a door? Is it a gunshot? What's happening? What caused that tug in your chest? Is it anxiety? Is it that you overate that you have heartburn from eating a too rich of a meal? Is it the beginning of a heart attack? Your brain actually doesn't know. It only receives the outcomes. It has to guess at what the causes are.
This is called an inverse problem. You know what the outcome is, you don't know what the cause is. And so your brain has one other source of information available to it. And that is past experience, memory. So it's not like you walk around consciously remembering things in order to perceive the world. Your brain is constantly remembering, meaning it is constantly reassembling bits and pieces of past experience in order to make sense of what's going on in the body, in relation to the world so that your brain knows what to do next.
Because frankly, if a loud bang is a door slamming, you would do something different in a particular situation than if it was a gun fire, if it was a gunshot. And so what your brain is–if you were to anthropomorphize a bit, you'd say, what your brain is constantly doing is it's asking the question, what is similar in my past? What is similar to what this sensory array looks like and what caused it, and what did I do about it and did it work? Now in psychology, things that are similar to one another are category. So your brain you could say is constructing categories. It's a category construction organ. It's constantly using the past to construct categories to make sense of the present in order for the purposes of guiding action and regulating metabolism. But we also know that a representation of a category is a concept.
So you could say also that what the brain is doing is it's doing concept generation. Ad hoc concept generation. Your brain is constantly remembering, reassembling past experience as concepts that are tailored to the specific situation that you're in to make sense of what your body means in that particular situation so that it knows what to do next to keep you alive and well. And that's what emotions are. Emotions are just when your brain uses past experiences of emotion to make meaning of the present and guide action.
Mills: If emotion is something that our brain creates, then can we will ourselves to feel emotions differently? I mean, how much control do we actually have over our emotions?
Barrett: Well, I would say that we definitely can, but it's much harder to do then actually, sometimes we make it out to be, and every client that every therapist has ever had knows this to be true. It's actually very, very hard to do. And also what it means is that what control looks like doesn't only happen in the moment when a person wants to change how they feel. So one thing I haven't done is made the distinction between affect and emotion. And that's a really important distinction in the science that we do. Emotions are easier to change.
Affect is not as easy to change in the moment. So let me back up a little bit and explain that distinction. And then I will answer your question. Your brain is always controlling your body and your body is always sending sense data back to your brain. And for the most part, we are not aware of all of those sense data to the same degree that we're aware of sights and sounds and smells and things. At least I hope you're not. If you are aware of what's going on inside your body, I feel really bad for you because it means that you've got a whole drama unfolding there. And if you're aware of it, that means that you're probably in significant discomfort and I'm really sorry.
But what evolution has done is made available that information to us as affect, as simple feelings. I feel pleasant, I feel unpleasant. I feel worked up, I feel calm. I feel comfortable. I feel uncomfortable. So your brain is regulating your body 24/7. Your body is sending information back to your brain 24/7 and you feel affect 24/7, regardless of whether you're emotional or not. You feel affect. Affect is universal. Now what affective features are associated with different things is not necessarily universal always, but affect is universal. The ability, the capacity to have that affect is universal and most likely all mammals and many vertebrates, probably maybe all vertebrates and maybe even some invertebrates can also feel affect. That's an interesting morass of confusion there, but it's interesting to talk about and think about. But I would say affect is definitely not a human-specific ability.
And sometimes when we're making meaning of the sensations and the affect that goes with it, sometimes we make episodes of emotion by again, creating categories or concepts on the fly. In fact, there's a convenient term called a conceptual category, which means that the concept, that knowledge is what makes a bunch of things similar to each other in a category, because a bunch of things can be similar to each other by virtue of their function, not by virtue of what they look like or smell like, or sound like or taste like.
And many things that we deal with in life are categories of that sort, and infants learn those kinds of categories in the first year of infancy, they're called abstract categories where, what the similarity that draws the instances together are not perceptual. They are functional. That is, they serve some kind of function. And this is something I talk about in Seven and a Half Lessons. And so affect is hard to change because you don't have volitional control over your heart or your lungs, and–you do have volitional control over your breathing, and you can try to practice breathing in order to calm your heart and control your heart and so on and so forth.
Mills: But you can't stop your blood from flowing.
Barrett: No. And so you can't. It's really, most people can't speed their heart up just by thinking about it. And so affect is actually really hard to change without drugs, like in the instant. And that's really often why people use drugs, both prescription chemicals and unprescribed chemicals, because they're attempting to relieve discomfort or distress, which is affective in nature. But you definitely can change how you make sense of affect and the sensations that give rise to it. And but they're, I would say in the moment, for example what would James Gross and others call, reappraisal is just, you could think of it mechanistically as your brain is re-categorizing the set of sensations, is recategorizing what they mean. That is, it's conjuring a different category, a different concept to make sense of those sensations and therefore give rise to a different action.
So in the moment you can do that very deliberately, but sometimes even that is really, really, really hard to do. And one way to have more control over your emotions, in addition to just keeping, making it easier for your brain to regulate your body, which is like get enough sleep, eat healthfully, surround yourself with people who care about you and who you love and have good relationships with. In addition to those things, you can learn and practice re-conceptualizing, that is changing the categories that your brain can make easily. So it's like exercise, or like driving. First of all, it is like exercise because it's very effortful to do this. And so it's like an investment in a healthier you, but it is also like driving where at first it's really hard, but then when you practice it really a lot, it gets easier and pretty automatic.
So you can take anxiety and turn it into determination or exhilaration even. You can take anger and turn it into awe. The affects stays the same, but the meaning is what's changing. And if you practice in advance, you're seeding your brain to be able to do this much more automatically. So for example, I'm skeptical by nature but there is research to show that gratitude and compassion and all are very good for your nervous system and therefore for your mental health. And right down the hall from me is a colleague who studies gratitude and the importance of gratitude. So I'm like, okay, fine. All right. I'll try it. And so I set myself the task of, gratitude I was already on board with, but awe was a trickier one. So I thought, all right, I'll try to cultivate a sense of wonder for five minutes every day where I'm a speck and therefore my problems are a speck, and let's see if I can do it.
And sure enough it was hard at first, but I did it, just like I learned to hold a plank for a minute or two, whatever. And eventually it became really easy. And now I can switch in and out of that particular state, my brain can make it easily when I need it and give my nervous system–if you're a speck for a minute, your problems are too a speck for a minute, and that gives you a break for a minute. And that changes how you breathe and it changes how you comport your body and it changes what you do next.
So a lot of the things that we know by different names, we misunderstand the mechanistic way in which they occur, right? So appraisal or reappraisal is a description of something that happens. It's not an explanation of the process that produces it. And by understanding how your brain works, you can generalize that process and start using it in new other ways. So for example, you can learn other emotion concepts from other cultures that don't exist in our culture, but that might be really useful for helping you to make sense of your affect and the sensations that give rise to it so that you can broaden the repertoire of actions that you can potentially take. And we know from the wonderful work of George Bonanno, that flexibility is the key to resilience in any situation, even a really stressful one. And so that's a way you can control your emotional life, cultivate your emotional life, architect your life, architect your experience in a way that is before the heat of the moment.
Mills: So what are the big unanswered questions in your field and what are you working on now?
Barrett: Oh my God. Well, I have a lab of 25 full-time people and 100 or so undergraduate researchers. So we have many, many questions that we are trying to understand. But one thing we're trying to understand for example is, the name for your brain sensing your body is called interoception. And usually interoception is studied as your awareness of your physical sensation. Are you aware of your heartbeat? But that's really a very small part of what interoception is. Your brain is estimating the state of your body. It's modeling your body, basically. And most of that state estimation is happening outside of your awareness at all completely. You just have no awareness of it. And so that's a question we're really interested in. Not the question of like, are you aware of your heartbeats. But how well is your brain actually tracking what's happening in your body?
Because one cause of depression, for example, could be that your brain has a mistaken model of your body. And there's some disconnect there. So that's one thing that we're really mechanistically trying to work out. Another is, in the way that we understand somethings, that we think something first and then we act, or we think something first, and then we feel something. So we go in and we try to tinker with how people think in order to change how they feel and what they do, but actually the way the brain works is that your brain prepares your actions first and your experiences derive from that. It's not the other way around. And this is also something that I explain in both books actually. And there's a very strong likelihood that what's happening is not that you think bad things, and then you feel bad, more like you feel bad, and that leads your brain to think bad things.
So it could be that there are problems with the way that your brain is modeling your body, or literally problems with your body. For example, maybe your mitochondria are not as effective as they need to be. And that could be a source of depression. That could be a source of this disconnect. Your brain is attempting to model your body. Your body's not functioning well in this really subtle way that you would not be aware of, but maybe you'd just be aware of feeling bad. And that that is actually what's driving those negative thoughts. Not the other way around.
To me this seems first of all, very plausible from a neuroscience standpoint. And what it means is that when we go in and we get people to change how they think in order to change how they feel, what we're doing is actually just breaking a cycle. We're not changing the cause of the problem. We're just interrupting an ongoing cycle. And again, I would say there are real lessons there about things that you might want to do differently if this is–It's not that what we're doing is bad, it's just that there might be additional things that we might want to think about doing for treating mental illness.
Mills: Well, it just sounds amazing the work that you're doing. I really appreciate taking the time to speak with me today. And I highly recommend, I mean maybe I shouldn't say this, but I think your new book is very accessible and a great read. So I appreciate the time that you've taken. Thank you.
Barrett: Thank you. Thanks. Thanks very much.
Mills: You can find previous episodes of Speaking of Psychology at www.speakingofpsychology.org or on Apple Stitcher or wherever you get your podcasts. If you have comments or ideas for future podcasts, you can email us at speakingofpsychology@apa.org. That's speakingofpsychology, all one word, @apa.org. Speaking of Psychology is produced by Lea Winerman. Our sound editor is Chris Condayan.
Thank you for listening. For the American Psychological Association. I'm Kim Mills.
Lisa Feldman Barrett, PhD, is a university distinguished professor of psychology at Northeastern University, with appointments at Harvard Medical School and Massachusetts General Hospital. Her research focuses on how the human brain, in continual conversation with the human body and the world, regulates the body and creates mental events, such as episodes of emotion. In addition to the books Seven and a Half Lessons About the Brain and How Emotions are Made, Barrett has published over 240 peer-reviewed scientific papers appearing in Science, Nature Neuroscience, and other top journals in psychology and cognitive neuroscience, as well as six academic volumes published by Guilford Press. She has also given a popular TED talk with over 6 million views.
