How do our brains create emotions?

- Hello everyone. I am Chris Hyams, CEO of Indeed. And welcome to the next installment of "Here to help". This is our look at how Indeed has been navigating the global impact of COVID-19. Today is September 27th, we are on day 573 of global work from home. At Indeed, our mission is to help people get jobs. And this is what gets us out of bed in the morning, and what keeps us up at night and people are at the center of our business, which means that the better we understand people, the more helpful we can be. I am very excited to introduce our very special guest for today's episode, whose work is centered around understanding people, in particular, understanding how our brains work. Dr. Lisa Feldman Barrett is among the top 1% most cited scientists in the world for her revolutionary research in psychology and neuroscience. She is University Distinguished Professor for Psychology at Northeastern University. She also holds appointments at Harvard Medical School and Massachusetts General Hospital where she is Chief Science Officer for the Center for Law, Brain and Behavior. Dr. Barrett is the author of the remarkable books, "Seven and a Half Lessons About the Brain" and "How Emotions are Made". She has also 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 given a popular Ted talk with over 6 million views. Dr. Barrett, thank you so much for joining me today.

- It's my pleasure to be here and chat with you.

- Let's start where we always start these conversations, by asking, how are you doing today?

- I am hanging in there. I'm hanging in there, you know, I had a walk this morning. I'm trying to pay attention to the beautiful sunny day, these little shifts in attention help. How are you?

- I am doing well. I'm actually looking out the window at some cows and donkeys out in the country today. And it's a nice change of scenery. I had been sitting in my same office for about 17 months. And so it was nice to have a little shift. Well, so let's start. You are a neuroscientist and a psychologist. Can you give for the folks who are not familiar with your work a little bit about what it is that you do?

- Sure. Well, I started off studying the nature of emotion. So really the question is when you have feelings of happiness or awe or anger or sadness, exactly what is your brain doing in conversation with your body and the rest of the world around you? What is your brain doing actually to create those instances? And that requires using tools from lots of different domains in science. And it turns out to be a really good kind of flashlight into just basic questions about human nature and how your brain works and how it creates the mind that you have.

- So the first lesson in "Seven and a Half Lessons About the Brain", which is the half lesson, is that the brain is not for thinking, which I think probably most of us thought originally. So can you explain what exactly is the brain for.

- Sure. I just got really interested in the question of why do we even have a brain 'cause brains are hugely expensive organs right. That three pound blob of meat between your ears is about 20% of your metabolic budget. And so I thought, "Well, brains are really expensive, so exactly what are they good for? Like why did they evolve?" And so I actually went back and started reading work in evolutionary and developmental neuroscience to try to understand when did brains evolve, how did they evolve and what is their most important function? And it turns out that you can see this also in the structure of the brain as well. The brain's most important job is not thinking or feeling or seeing, or hearing or anything to do with detecting things in the world. The brain's most important job is regulating the systems of the body. So right now, as we talk, you know, and as our listeners listen, there's a whole drama going on inside each of us with dozens of systems that have to be coordinated and where energy regulation has to be taking place. So the brain, it isn't concerned, you know, when I use this metaphor like body budgeting, right? The brain isn't really concerned with budgeting money. It's concerned with budgeting glucose and salt and water and oxygen and all of the nutrients that all of the systems need in order for you to stay alive and well. And that really is your brain's most important job. When I wrote this in the book, and I wrote an op ed about it in the New York Times, I got a couple of very angry emails from my colleagues in cognitive science saying, "What do you mean the brain's most important job isn't thinking?" And I was like, "Well, I could give you all of the neuroscience evidence, you know, or you could just read the appendix of my book," but I could just say to you, "Well, if your brain isn't regulating the systems of your body, you die. So I guess I win." You know, like it really is your most, it really is. But I think there's a lesson in there that, you know, we evolved the capacity, animals evolved the capacity to see and hear and think and feel in the service of regulating the body. And of course we don't experience ourselves and our lives that way. We don't experience every hug we give, and every insult we bear and every beautiful scene that we see, or every irritating thing we'd read in the newspaper. We don't experience the world that way, but that is actually what is going on under the hood. And you can see it in the anatomy and the organization of the brain as well. And I think there are some clues there for, you know, how to live a life that's closer to the life that you want to live.

- So the brain's primary function is this body budgeting. And then as you go on to describe, the brain is really a prediction machine, which is a revelatory concept. Although as a computer scientist, it makes a lot of sense. I'm sort of interpreting all of your work through the lens of what I understand about how computers work and in particular machine learning and artificial intelligence systems that we work with, they operate exactly the same way. We utilize our prior experience or data to make predictions about future events. And then we take actions based on those predictions. So one of the things that you describe is that we basically don't directly experience the world around us at all. We think that we are experiencing things directly, but what's happening is that our brains are constructing reality as a simulation. You even use the word hallucination in which it all feels very much to me like we actually do live in "The Matrix". So can you explain a little bit about this prediction machine and about the simulation?

- Sure. So let me just say that there's so much in what you said, Chris, that we could just pick up on and talk about, but I'll just suggest that, you know, since the enlightenment perhaps, you can look back and see philosophers who are suggesting that humans come to the present moment with prior knowledge that they're using somehow. And so the idea that we bring to bear past experiences in order to construct our experience of the present is not a new idea. I think for me though, I'm just like inherently skeptical person. You know, science didn't make me skeptical. I think I'm a scientist because I am skeptical. But what I found really convincing is because of course we don't experience, again, our experience of ourselves in the world is not that we predict what's about to happen next and then, you know, it's that we react to things, right? You see something, you hear something, you react to it, but there is evidence from lots of different domains of science, including cybernetics, that really clearly show that what the brain is doing actually is predicting what's going to happen in a moment from now. And, actually it's not that we're predicting what's going to happen in the world and then we take actions based on that prediction. It actually is the other way around. If we were to stop time and we consider this time zero, the brain is modeling essentially what is going on inside its body and in the world. So you can think of your brain as being trapped in a dark silent box called your skull. And it's receiving sense data from your body and from the world around you. And that sense data, the sense data that hits the sensory surfaces of your body, like your retina in your eyes and your cochlea in your ears. And you have all kinds of sensory services internally inside your body, which are sending information continually to your brain. Those are the outcomes of some set of changes that are happening, but your brain doesn't know what the changes are. It only knows the outcomes, so it has to guess at the changes. Now consider for example, if you hear a loud bang, there are so many things that that loud bang could be that there's tremendous uncertainty. So that loud bang could be a car backfiring, it could be a door slamming, it could be thunder. And, you know, forecasting a big rain shower. It could be a gunshot, if you're in the United States in certain parts of the country, there are many things it could be, and it's very metabolically expensive for a brain to try to deal with all of that uncertainty and plan what to do next in order to keep itself alive and well. So there's, you know, evidence from cybernetics actually, that the best way to regulate a system is to model it, make predictions about what's going to happen next and then correct those predictions. And that's actually the most energetically effective way to reduce uncertainty and sort of deal with things. And so that's really what the brain is doing. It's taking this moment right now that it's modeling and it's making a set of predictions about what is going to happen next. And when I say what is going to happen, what I mean by that is the first aspect of those predictions are motor and visceral motor, meaning to control the viscera inside your body. So predictions begin with adjusting your breathing, your heart rate and so on to allow you to prepare to make motor movements. And it's the consequences of that preparation that become the predictions of what you will see and hear, and smell and feel. So your brain is always preparing you in advance for what you should do next based on your past experience in situations that are similar to this. And the copies, literally copies of those signals are sent to the sensory systems of your brain. As you know, we could call them, scientists call them simulations, or they call them perceptual inferences, or they call them just simply memory, but they are what philosopher Andy Clark calls controlled hallucinations. And I independently came up with the idea of these being hallucinations. I think in 2012, I started referring to them as hallucinations, but I like Andy Clark's description a little bit better adding the controlled bit, because really they're not hallucinations that are unconstrained by reality. Those predictions, so sensory predictions, the perceptual inference is really what your brain is doing is it's changing the firing of your own neurons in your brain. Your brain changes the firing of its own neurons to prepare you to experience yourself in the world in a particular way. And then the data come from the world and from your body and constrain those predictions. Either confirm them or correct them. So it's not unbridled hallucination, it's hallucinations that are sort of entrained, in a sense, by the world and your body.

- So maybe a little less "The Matrix" and a little more, what you're describing is exactly how computer vision systems work like the components of a self-driving car, where it's taking input from the outside, it's modeling, that looks like a tree, that looks like a cyclist, and then makes decisions about swerving to avoid the thing that looks like a cyclist.

- If you look in the visual neuroscience literature, you know, it's intimately tied with computer vision work. That's some of the best evidence for predictive processing in the brain. And then if you look in the motor neuroscience literature, again, you see really good evidence that the brain is predictively regulating your skeletal motor movements, the movements of your limbs and so on. And so there are these different literatures that don't really talk to each other very much where you see evidence for almost every sensory system. And then, you know, I, a number of years ago, actually, I was reading some neuroanatomy and I realized that the circuitry in your brain that is at the top of what we would call the predictive hierarchy, so it's like the boss of prediction, right? It's the areas that are where predictions are launched in the brain, is our limbic. And for people who don't know what that means, these are regions of the brain that for many years, people thought were emotional, but they're not emotional. They're not regions of the brain for emotion. These regions of the brain are implicated in almost every psychological phenomenon, every psychological event you experience. But most importantly, they are the regions that are important for regulating the body. Their main job really is to regulate the peripheral systems of your body, your cardiovascular system, your respiratory system, your immune system, and so on. And so this is really good evidence that, you know, these parts of the brain are not part of your, like some inner ancient inner beasts that have to be controlled by cognition. They really are predicting all the time, what needs to happen inside your body so that you can move in whatever way you know, the brain is estimating is the best way. And they are helping to dictate literally what you see and feel, and hear, and smell and so on.

- So let's actually jump in and talk about emotion. So we've established, our brains are primarily responsible for regulating body budgets and then for making these predictions. Can you explain the role of affect, which are these simple feelings of pleasant or unpleasant or idle or activated, and how emotions are constructed. And I recognize in asking this question that this is basically a huge amount of your life's work, and you wrote a 450 page book on how emotions are made. So I'm asking for a short answer on how emotions are made up, but forgive me for asking for the simple explanation here.

- No, no, no, I appreciate the caveat there. I'll answer, but I'll just say, honestly, if I wasn't a scientist, I'm not sure I would believe it just because somebody said it and I would just encourage everyone who's listening, not to believe what I'm saying, just because I have a doctor, you know, in front of my name, I really think that the evidence to me is really striking. And the evidence comes from lots of domains of science and in science, how we know something, you know, we don't like the word. We don't like the F word in science. You know, fact, we just don't like it. It's because everything is probabilistic and contextual and so on, but scientists have agreed that we sort of come closest to a fact when there's good consensus in the scientific evidence across literatures, and that's what we have here. So what I'm about to say is not just an idea, right? It's actually backed up by really hundreds, if not thousands of empirical studies across many different literatures that don't speak to each other. And the story basically goes like this. So your brain is always regulating your body and your body is always sending sense data back to your brain. So your brain's modeling the sensory state of your body. And there's a lot of complicated stuff going on in there that you are largely unaware of. I hope for your sake, anyone who's ever had, you know, like appendicitis or GI distress, or actually has ever been pregnant, knows exactly what I'm talking about. So, you know, we are not really wired to experience every little change in the sensory conditions of our own bodies, 'cause if we were, we would never pay attention to anything outside our skin ever again. Instead, what our brain does is it gives us just sort of a summary of the state of our body budgets. And that summary is what we experience as affect or affective feelings, or you might call it mood. So feeling pleasant, feeling unpleasant, feeling worked up, feeling calm, feeling comfortable, feeling like shit, I mean, basically that's you know, it' these really kind of simple feelings. We can think of them as low dimensional sort of compressed summaries of all of the actual physiological drama. And so your brain is always regulating your body. Your body's always sending sense data back to your brain. So you always have some experience of affect, always, your whole life. And these are features of consciousness. They are not specific to emotion, episodes of emotion per se, but when affect is intense, meaning that either there's been a drastic change in your body budget, or it's an unexpected change, or there's some big reward or big threat that is being predicted in the future or the brain is having trouble predicting. In which case it's going to attempt to learn something new. It's going to attempt to adjust its internal model or its predictions to something new, which requires chemicals that will make you feel aroused. And I don't mean sexually aroused. I mean, like worked up and jittery or really attentive. These feelings, simple feelings, which are always with you, tend to be associated with episodes where your brain is making sense of the sensory changes as emotion. So emotions are really how your brain makes sense of the sensory changes inside your body that it's predicting in relationship to the sensory changes in the world. So if I feel a tug in my chest, that tug could be indigestion if I just ate. That same tug could be anxiety if I'm in a doctor's office waiting for a test results, and it could be the beginnings of a heart attack, if you know, I'm waking up in the middle of the night or actually at any time of day. And the thing is that the tug is the same, right? Because your brain's receiving only the outcomes, the sense data that you're aware of as sort of this uncomfortable feeling. And it has to guess at what the causes are. And those guesses are actually constructing your experience.

- All of this that we just covered is sort of the prerequisites for the practical part of the conversation here, which is what does this all mean for us to understand that? So how does an understanding of these systems and what's actually going on in my brain and my body, how does that help me or people in our daily lives?

- So the way that it helps us is that emotions and really every event that your brain constructs, to make meaning of these sensory changes are prescriptions for action. That's what they are. Remember first, what the predictions begin as, you know, preparations to do something. And then the consequence of that is that you experience the world and yourself in a particular way. So the reason why this is important is, that how you make sense of those sensory changes really influences what you do next, which can change the trajectory of your whole life. And I know that sounds like a bit of hyperbole, but it's not actually. And it's also important to realize that the situations that you cultivate for yourself actually have a really big influence on the direction of your brain's predictions. So you have much more control over the direction of your life and really who you are as a person than you might imagine. It's just that the nature of the control isn't the way we traditionally think about it. So when we think about control, we usually think of, oh, you know, we have this knee jerk reaction, like our inner beast sees a second piece of chocolate cake, and we really want to have that cake. And, you know, we have to stop ourselves, right? Or, you know, we were in a meeting or, you know, we're talking to a family member or whatever, and, you know, somebody you know does or says something and we have to sort of hold our tongue or, you know, we're sort of holding ourselves back from these reactions that will just bubble up from our inner beast. And that's just really not how the brain is working. It feels that way. And we don't really know why exactly brains conjure these experiences that are so different from actually how the brain works, but they do. That our brains are like magicians in this way, right? They conjure experiences for us that for themselves, I guess, we are our brains. We can't escape Cartesian language in English unfortunately. But, you know, brains conjure experiences that don't reveal actually how the brain itself works. And so once you know how your brain works, you have a set of tools that you didn't have before. And I'll just give you one really, really, really, really simple example from my own life. You know, when I was in my early fifties, I was really tired, like really exhausted. And I didn't know why, but I was really fatigued. And I went to a doctor. It was a new doctor. So it was a new primary care physician. I went to the physician and I said, "I'm really exhausted." And he said, "Well, maybe you're depressed." And I said, "Yeah, I don't think so though, because I don't have any of the diagnostic criteria for depression other than I'm really fatigued." And he was like, "Well, maybe you're depressed and you don't know it." And I was like, "Well, maybe, but honestly, I'm just really fatigued." And he's like, "Well, maybe you're so stressed." And I'm like, "Well, I am stressed. I run a big lab, but I'm not any more stressed today than I was five years ago. And I'm really, really tired." Anyways, long story short, you know, if I had listened to him, he was really inviting me to construct my experience in a particular way. If I had listened to him, he would have given me antidepressants. And I probably would have been looking around in my life for the things that made me depressed. And I'm sure I could have found a bunch because you know, all of us, we all live very complicated lives, but as I was leaving, feeling very puzzled by the whole thing, a nurse pulled me aside and she said, "Sweetie, are you peri-menopausal?" And I was like, "Yeah, I guess, I'm, yeah." And she's like, "Here's a book you should read." And she gave me the self-help book and I started to read it. And then I went and started digging around in the scientific references and sure enough, estrogen, testosterone, sex hormones are metabolic regulators. And we all lose them. You know, men lose testosterone slowly over the lifespan. Women lose it drastically during menopause. They, you know? But we all, as we age, our bodies become less metabolically efficient in part because we are losing one of the sets of chemical regulators, which are our sex hormones. And that requires a whole different set of meanings and actions that take me down a really different path than depression. Now, I'm not trying to suggest that depression isn't a real thing because it is, it's actually a state of profound body budget bankruptcy, is the way that I would describe it. And I'm not saying that you can just change the meaning of your sensations and somehow through a set of Jedi mind tricks, like, you know, have your distress kind of disappear. But what I am telling you is that you have a lot of control over how you make sense of things, and that control leads you to do different things, which then sets up a whole set of other options that you wouldn't have necessarily had before. Another example is test anxiety. This is an example that I think I use in both books actually, because it's just so remarkable, You know, test anxiety, I think I talk about in the Ted talk too, is profoundly disabling for people. Sometimes it prevents people from passing courses or even getting a college degree and a college degree changes your earning potential substantially for the rest of your life in the range of hundreds of thousands of dollars over your lifespan. So, you know, your pounding heart and your sweaty hands and your racing mind, you know, all of these things can actually be understood in a very different way. You can make very different meaning out of this. And when you do that, and there are studies which show this, when people make different meanings, a different set of predictions about what these sensations mean, they can pass the test, they can finish college. Which has a huge impact on their earnings trajectory for the rest of their life. So this is really powerful stuff, but it requires patience and practice like any skill, to learn how to take control of the meaning-making in your life.

- Let's bring some of this into the arena of our mission at Indeed, which is helping people get jobs. I think what you were just describing about test anxiety, that probably is a good analogy to people interviewing for jobs, which can be stressful. And so I can see how that understanding of what's going on can help people to overcome some of those things. Let's jump to the other side of that interaction, which is employers interviewing candidates. And in doing that, employers are attempting to assess another human being for their character and capability in some purely objective way. Your work suggests that we are not well-suited or maybe even capable of true objectivity. And one of the examples you cite is the famous 2011 study of judges in Israel, of how affect can cloud rational judgment. Can you talk a little bit about this and how it might relate to what's happening in an interview process?

- Sure, I absolutely can. I mean, I think it's really important that everybody just realize that objectivity is a myth. It just is a myth. It's not possible for you to be objective given the way your brain works. Your brain is always making guesses in advance of everything that happens based on your past experience. So you, your actions and your experience are conditioned on your past. That's just a fact. There's the F word again. It's as close to a fact as we have really, in neuroscience, I think, and brains that don't predict well, are non neuro-typical brains. I mean, people who don't predict well, usually there's something not typical about the architecture and the function of their brain, and they suffer for it. They suffer in serious ways. So, you know, what this means is for the scientists among us, you know, we would talk about this as bias, not bias with a big B as in, you know, racial bias or prejudice or stereotyping, but bias in the signal detection sense that you're never a blank slate when you come to a situation. You're always bringing your past along with you. And we talk about that past as baggage, but if you didn't have that past, you'd be experientially blind to everything that you encounter. You wouldn't know. You would be like hearing noises and seeing, you know, flashes of light and not actually being able to make sense of them because you have to use your past experience and therein lies the tricky bit. Okay. So that's one aspect I think that's really important. Your brain is fluidly, automatically, effortlessly using your past to predict and literally prepare to experience the immediate future, which becomes your present. And sometimes the fluidness, the fluency with which we use our past experience, our brain is assembling memories to guide action and construct experience, the fluidness with which we do this makes us think that we're objective or that somehow what we're experiencing is the natural order of things, but it's really not the case. And, you know, scientists sometimes will say, "Well if, you know, two scientists see something and they agree then that must be an objective view," but that's just confusing consensus and validity. Right? And so I think that's the first thing that's really important, but every decision, every situation you come to where you are in control of somebody else's outcomes, you are bringing a whole set of lenses to that situation, which may or may not be disadvantaging that person or advantaging them in some way. The second piece that's important, and, you know, the judges, the Israeli judges study has been a very controversial study. Like there are a number of criticisms that have been raised for this study, but I don't think any of them actually counter the interpretation which I'm giving. And there are many other studies that are about job interviews and about interviews for medical school and you know, where people use their affective feelings as evidence for the validity of their judgments. Your brain isn't really making sense of affective feelings. It's making sense of the sensory conditions of the body, which give rise to those feelings. And so what this means is that when you feel unpleasant, your brain is going to be trying to make sense of the sensation, the sense data from your body that give rise to that unpleasantness in relation to what's going on around you in the world. So the findings of this study are that when judges are feeling unpleasant, right before lunch, they give harsher sentences than, you know, they do at the beginning of the day, or when they're not hungry, basically. And there are findings like this about the weather. You know, people actually, if you interview for a job or like a position in a professional school on a rainy day, you are at a disadvantage because people feel worse on rainy days than they do on sunny days. And I think one of the estimates was something like, it costs you some number of points on your MCAT, you know, like the equivalent of some number of points on your MCAT. So I think the important thing to understand again, is that, you know, your brain is constantly tracking the sensory conditions. It's modeling the sensory conditions of the body, but it doesn't know really what's going on inside your body. It can't know. It's just getting the consequences of the changes. And it has to guess at what the causes are based on your prior experience. And so feeling strongly about something isn't necessarily a good piece of evidence that what you are thinking is true. Although we tend to think of it that way. So if you're talking to these judges, we're talking to potential parolees, and you have an uneasy, uncomfortable feeling as you're talking to them, that may not be evidence that they're untrustworthy. It may be evidence that you're hungry or you're tired, or there's, you know, something else. One of the other multitude of things that could be affecting your body budget, is actually helping to cause that really unpleasant feeling and many, many mistakes are made this way.

- You talked about bias with a little B, let's jump for a minute, actually to bias with a big B. We all know the impact of discrimination in areas like the criminal justice system, education, health care, and housing. In many ways, employment is foundational for all of these issues. So working to understand and mitigate bias in hiring is really central to our mission at Indeed. How does this understanding of the brain give us some insight into the mechanisms of bias and how can this understanding maybe help us to counteract?

- So, I mean, there's so much to say about this. It's very well known that there are structural biases in the workplace, in healthcare, in education. There are these structural biases where certain people are advantaged over other people on the basis of physical characteristics, are assumed to be predictive of something about ability or trustworthiness or what have you. In the legal system also as well. So there are structural problems in place that disadvantage certain people in favor of advantaging others, but those structural problems are put into play by people. And they're by the brains of people and they're maintained by the brains of people. So I guess Chris, what I'm trying to say is, there are two ways to describe what you're asking me. One is at the level of an individual person and their actions and the other is, how did those structural inequities get there in the first place and how are they maintained? Those are two different ways of answering the question that you asked me. With respect to an individual person, what I would say is, look, if you're in a crappy mood, you are literally more likely to see someone with a neutral face as like scowling at you. And if you're in a pleasant mood, you're literally more likely to see someone as more likely to be smiling at you. So resting bitch face, right, is actually a person with a neutral face. It's actually a person with a neutral face, structurally neutral face. We've actually studied this, but you as the perceiver have an expectation, a prediction that the person's going to be a bitch. And so you actually see their face differently, right? And so, what does this mean? It means that it's not just your interpretation of your experience. It's actually, your literal experience could be different. Similarly, if you grew up in an environment that is mostly where people mostly look like you and talk like you, smell like you, then when you encounter someone who's different from you in some obvious way, physically different from you in some obvious way, your brain's going to have a harder time predicting what that person's going to do next. And that's going to make you feel not good because when your brain can't predict, it's going to attempt to learn. And the two most metabolically expensive things your brain can do. One of them is moving physically, your body. And the other is learning. Learning is actually physically costly. It's a metabolically costly endeavor. And usually it's a great investment, right? For the future. But in the moment it can feel like shit. And so if you grew up, if you as an infant or a young person, or even throughout your life, or on television, you know, you were mostly encountering people who were very similar to you. And then you're when you're faced with someone who's very dissimilar. Your brain's going to have a hard time empathizing with that person. It's going to have a hard time even predicting what that person is going to do next. And you're going to feel uncomfortable interacting with that person. And you will interpret that, even make sense of that. Not just interpret, but make sense of that experience, that discomfort as evidence that there's something wrong with this person or that person's not trustworthy in some way, or the person is not competent. And again, this is actually research that we've done in the lab. This isn't conjecture. We can manipulate people's affect without their knowing and then we can have them interact with other people, or just even show them pictures of other people. And when you're slightly feeling unpleasant, the person that you're interacting with is less attractive, less trustworthy, less competent, less reliable. These are the expectations you come into an interaction with, right? Why do physicians, largely white physicians, largely under dose people of color? Even children with medicine, with pain medicine, but with antibiotics, with I mean, this is structural racism. And you know, the reason why, one reason why, is that they empathize less well with people who look different than them and who sound different than them. And that empathy, lack of empathy reduces their prescribing or like changes their prescribing behavior. And when I say lack of empathy, I'm not trying to be judgmental. I'm actually trying to be scientific in my description here. I would also say that, you know, for the last hundred years, most of medical research was conducted by men on male animals. And as a consequence, some very basic types of pain like menstrual pain, which happen every month to a large portion of the working population, no one has a cure. No one really even understands how it's caused. There are millions of women who suffer on a monthly basis really seriously because men can't have empathy because the people in charge of the medical research didn't find this particularly compelling or interesting 'cause they don't experience it. And again, I'm not being a raving woman about this, when I say this, I'm just saying that these are big biases, big B biases, that come from the typical way that brains work.

- The opposite of this is exposure to diversity. And so, you know, as an employer and like many employers, we recognize the importance of diversity in the workforce. We've all seen the same social and economic research that suggests that diverse teams are more creative, they're more innovative, they think about and care about their customers more and they create better products and services. When we were meeting last week to talk about this, I was excited to hear that there's also a brain science explanation for the benefits of diversity. Can you talk a little bit about that?

- Your brain doesn't forage for information all the time. It's actually selecting what it pays attention to. So your brain isn't modeling every single thing that's happening in the world. And it couldn't 'cause there's just too much. It's selecting. So there's a likelihood that if something isn't placed right in front of you , you're not necessarily going to go searching for it. You might not be aware of what's missing. And if what you're encountering just automatically makes sense to you because it's very familiar, that can feel like that what you're doing is right and obvious and natural. So one way that diversity works is it introduces novelty to people, novel information that they wouldn't necessarily go searching for themselves. And they wouldn't even know was available, you know, because it's just not part of their experience. So they wouldn't even know. But there it is, it's right there and it's easily accessible and maybe it's easily accessible by somebody who they've learned to trust. We are social animals and we don't just maintain our own body budgets. We make deposits and withdrawals, metaphorically speaking, in other people's body budgets too. And we learn from other people. Now we don't have to experience every single thing ourselves in order for that information to become part of our future predictions. We learn from each other. So one of the values of a diverse team, particularly when it comes to creativity and innovation is that new information becomes available to the team that they wouldn't necessarily have had before. And another important thing is that when your brain is conjuring predictions, it's not necessarily literally remembering, literally reassembling past experiences in exactly the same way every time. Your brain is doing what's called conceptual combination, which means it can take bits and pieces of the past and combine them in new ways. And that is, you know, a substrate of creativity. So if your brain can do this in the presence of novel information with other people who they value and trust, making the body budgeting burden of novelty and learning easier, then that is a recipe for, you know, successful innovation.

- You talk in "Seven and a Half Lessons About the Brain", lesson five is about your brain working with other brains in this essentially interdependent body budgeting that you just talked about. Right now, we're at this profound moment in history where on the one hand, we've never been more interconnected as a species because of technology. You and I are thousands of miles apart and having this conversation with hundreds of other people around the world right now who are listening into this. On the other hand, we are 18 months into a global pandemic that is forcing us to keep our own physical distance from one another. And the very nature of these connections has been essentially blown apart. So what is what's going on in the world right now? What does it mean for the world of work and for our species?

- Look, if you and I were in the same room and we liked each other, our first impressions were good, or if we knew each other for awhile and we trusted each other, our heart rates would synchronize. Our breathing would synchronize. Actually our heart rates would synchronize because our breathing would synchronize. Our physical movements might start to synchronize a little bit, you know? So if you put your hand on your chin, I might put my hand on my cheek. If you cross your ankles, I might cross my legs, you know, and who's leading and who's pacing, so who's, you know, following who might actually change, right, throughout the conversation. The physical signals that we emit by just by our body budgeting really have an impact on the other person that we're interacting with when we're in the same space as them, even if we're not touching each other. Although touch is also another really important way that we communicate with each other and that we can regulate each other's body budgets, both for benefit and for harm. You know, I mean like one of the basic rules, right, is that, you know, the best thing for a human nervous system is another human. The worst thing for a human nervous system is also another human. And, you know, you may have impacts on people when they are in your presence, when you're physically in the same place that you are unaware of, but you can make body budgeting easier or harder for that person. Without being in the same place, we lose some of that communication capacity. Some of those channels are lost, but on Zoom, for example, we can still get some of them because we can still see each other's movements. And we can hear the prosody, the changes in tone in each other's voices. And actually our brains can still pick up some information about physical signals, like the physical condition of the body. So for example, you know, I have lights on me right now. So your brain would be having a harder time, you know, picking up the subtle changes in skin tone that have to do with my blood flow. But if I were to pull my hair back and sit with my neck, exposed, a camera can pick up the heartbeat from my carotid artery, which likely means so can your eyes. And we're always encoding. We're always learning these things about each other under the hood. You know, we're not aware that we're picking up this information, but we are, and we're using it. So that information is still available. You know, when we're talking to each other, if I cut you off in mid-sentence, that could be because I'm rude, or it could be because I'm really enthusiastic about what you're saying, or it could be that we're having a problem with the connection because a satellite moved somewhere, right? And so it's all about, what are the meanings of the sensory cues in a particular situation? Now think about, you know, we're on the telephone instead of being on Zoom. Now you've lost a bunch of information but you still have the person's voice and you have their words. Or think about text, now, all you have are their words. So words and voice and face and other body movements and other physical signaling, all of these actually are ways that one human nervous system can impact another. And some modalities leave more room for ambiguity than others. And so it's incumbent upon us to fill in the gaps so that the other person's brain doesn't do it and guess wrong. And if we don't do that, then you know, there's a lot of ambiguity and a lot of mistakes can be made. And in general, ambiguity is very, very stressful for a human nervous system. It's more expensive and it's more taxing to your body budget. And I think everyone would acknowledge that. Everyone knows Zoom fatigue, and everyone realizes, I think, who is interacting on a regular basis with other people over electronic means, that it's a blessing and it's remarkable, right? But it also has costs associated with it fatigue wise, that other forms may not. And one of the reasons is, there's just a lot of ambiguity, a lot more ambiguity in the signals that are harder to resolve.

- Well, our time has flown by, and I have so many more things I'd love to ask, but just to wrap up. Both of your books end on very positive notes, talking about really that our brains are a source of strength. And then even our problems give us, you know, this capacity to build civilizations, and then we can build this sort of new reality together. So in the face of all of the uncertainty and worry in the world, what leaves you optimistic for the future?

- Well, you know, yesterday I took a walk and in my town, there was a festival day and there were all these people outside wearing masks, outside with their kids, with balloons and like the lot of celebration and people just really enjoying being with each other. And the whole thing really brought me to tears, honestly, because amidst, you know, real challenges, economic challenges, and challenges with climate and challenges with COVID and all of these things, which are really, really, you know, making major withdrawals on our body budgets, people, most people are kind, and they try to do their best for each other. So I'm not a Pollyanna and I could, you know, tell you all the things that give me great worry about body budgeting and persistent deficits in body budgeting. And it's the relationship that has to, you know, the emergence of authoritarianism. And I mean, you know, I'm not being a Pollyanna, but I think that what makes me optimistic is that our brains are wired to the world that we live in, right? You know, an infant brain is not a miniature adult brain. It's a brain that wires itself to its world, both its physical world and its social world. And we also, even though we don't as adults, we don't learn as fast as infants do , our brains aren't as plastic as theirs are, our brains are still wiring in themselves to the world that we partially create for each other. And all things considered, when all things are considered equal, most people, when you give them the information for how to not just make a better world for themselves, but also for their kids and for their neighbors and the people they work with, most people are really grateful for that information. And so that's why I'm optimistic. And that's really why I wrote the books, because I think knowing a little bit about how your brain works makes it easier for you to think about what kind of human you are and what kind of human you want to be and then enact that.

- Well, Dr. Barrett, I can't tell you what an extraordinary pleasure it has been getting to talk to you and really just immersing myself in your work as I have and how it's given me such a new set of tools and ideas to think about the world around me and how I'm experiencing it. And I'm really thrilled to get to share this with some other folks, but thank you so much for joining me and thank you for everything that you do.

- Thank you for the opportunity to chat and I hope we have a chance to do it again.