At the very beginning of her new book Seven and a Half Lessons About the Brain, psychology professor Lisa Feldman Barrett writes that each chapter will present “a few compelling scientific nuggets about your brain and considers what they might reveal about human nature.” Though it’s an accurate description of what follows, it dramatically undersells the degree to which each lesson will enlighten and unsettle you. It’s like lifting up the hood of a car to see an engine, except that the car is you and you find an engine that doesn’t work at all like you thought it did.
For instance, consider the fourth lesson, You Brain Predicts (Almost) Everything You Do. “Neuroscientists like to say that your day-today experience is a carefully controlled hallucination, constrained by the world and your body but ultimately constructed by your brain,” writes Dr. Barrett, who is a University Distinguished Professor at Northeastern and who has research appointments at Harvard Medical School and Massachusetts General Hospital. “It’s an everyday kind of hallucination that creates all of your experiences and guides all your actions. It’s the normal way that your brain gives meaning to the sensory inputs from your body and from the world (called “sense data”), and you’re almost always unaware that it’s happening.”
People tend to feel like we’re reacting to what’s actually happening in the world. But what’s really happening is that your brain is drawing on your deep backlog of experience and memory, constructing what it believes to be your reality, cross-referencing it with incoming sense data from your heart, lungs, metabolism, immune system, as well as the surrounding world, and adjusting as needed. In other words, in a process that even Dr. Barrett admits “defies common sense,” you’re almost always acting on the predictions that your brain is making about what’s going to happen next, not reacting to experience as it unfolds. (Michael Pollan details the same neurological process in his book How to Change Your Mind.)
“Predictions transform flashes of light into the objects you see. They turn changes in air pressure into recognisable sounds, and traces of chemicals into smells and tastes. Predictions let you read the squiggles on this page and understand them as letters and words and ideas,” Barrett writes. “They’re also the reason why it feels unsatisfying when a sentence is missing its final.”
In her first book, How Emotions Are Made, Dr. Barrett cites research that suggests something similar happens with emotion. We experience things like anger or anxiety as feelings caused by outside events. But really, as Dr. Barrett says, “Emotions don’t happen to you—they are made by your brain as you need them.” That may sound like splitting hairs, but the consequences are quite profound: The more you know about emotions, the more precisely your brain can construct them, so you will feel and act in ways that are very specific to the situation. We talk a lot about “handling” emotions after they emerge (this is called emotion regulation), but understanding emotions as something you construct allows you to influence how they arise in the first place.
Of course, this upends notions of how we experience reality and leads to some interesting questions. Why does this happen? If we construct the reality around us, including our emotions, does that mean we can change how we feel? What should we do with the anxiety and stress brought on by coronavirus? If our actions are dependent on past experience, do we control what we do? How do we think about responsibility—say, in the renewed conversation around police violence—in a world like that? How can we use these seven and a half lessons to better exist in the world? GQ spoke to Dr. Barrett to ask these questions and more.
GQ: Your first lesson, which is actually a half lesson, is that the brain is not for thinking. So then: what is the brain for?
Lisa Feldman Barrett: The brain’s most important job is not thinking or seeing or feeling or doing any of the things that we think of as being important for being human. Its main job is running a budget for your body—to keep you alive, to keep you healthy. So every thought you have, every emotion you feel, every action you take is ultimately in the service of regulating your body. We don’t experience mental life this way, but this is what is happening under the hood.
The technical term for body budgeting is allostasis. It basically means that your brain’s job is to anticipate the needs of your body and meet those needs before they arrive. Budgeting resources like glucose, oxygen, salt, and all of the nutrients that your body needs so that you can do your most important job from an evolutionary standpoint: pass your genes on to the next generation.
There are limited resources [in your body] and every action that you take—every movement that you make, every new thing that you learn—costs something. And so every time your brain prepares to move your body or to learn something new, your brain is asking itself, figuratively, is this a good investment? Is it worth it?
This is one of the most amazing, and unsettling, revelations in the book, this idea that the brain is a prediction machine. Instead of passively observing reality—in what we think of as a stimulus-response pattern—it’s actually constructing our reality?
We can use a baseball example. The batter walks up to the plate. He takes his stance with the bat. A major league pitcher throws at a speed of 80 to 100 mph, giving the batter between 400 and 500 milliseconds to react. This is not enough time to see a ball, then decide to swing the bat, plan the action, and execute it. But a brain that works by prediction is fast enough to make baseball possible as a game.
Here’s what’s really happening: based on all the information that the batter has about the situation, his brain is automatically computing the swing, making a prediction about, in a moment’s time, where will the ball be. And so in the blink of an eye, his brain predicts the action, and then predicts his sensations. Figuratively speaking, his brain predicts: “What will I do in a moment from now? And the last time I acted this way in this situation, what did I see ? What will I feel in my joints? When the bat strikes the ball, what will I hear?” His brain is automatically changing the firing of its own neurons to anticipate the sensory changes that will result from the crack of the ball against the bat.
And so what happens? Information is coming in through his eyes and his ears and the rest of his sense organs. If the new information matches the prediction, then his motor response is completed, he swings the bat as planned and probably hits the ball. If there’s a difference, though, if his brain has not predicted something, say there’s a gust of wind or something happens with one of his tendons, then his brain may take in that new information and automatically adjust its prediction. But that adjustment will take long enough that he could miss the ball.
Predicting and correcting is a much more efficient way to run a system than reacting all the time. So what your brain is doing all the time is making these guesses, and then comparing them to sense data from your body and from the world that is continually arriving, as a way of reducing uncertainty, which, it turns out, is the metabolically efficient thing to do.
The example that got me in the book was the fact that it takes 20 minutes for water to reach your bloodstream, so when you drink a glass of water and feel like your thirst is immediately quenched, that’s not a biological reality, but a kind of a neurological trick.
Here’s another one that I just learned. You know how when it’s just starting to rain, and you might feel one drop of water on your skin, and you can tell it’s going to start to rain? Well, you have no wetness sensors in your skin. So how is it that you feel those drops of water? Your skin has touch sensors and temperature sensors, and your brain is doing this internal calculus, integrating the information about touch with the information about temperature to construct a prediction of water on your skin. So when you feel wetness under your underarms or you feel dampness on your skin for any reason, it’s basically a construction of your brain taking two sources of information and combining them.
Every single thing that you do, and every single thing that you feel and think—basically everything you experience—is some combination of what’s going on inside your brain and what’s going on outside your skull. Your brain doesn’t know for sure what’s going on in your body. It’s only receiving sense data. That sense data is the effect of some set of causes that are going on in your body. But your brain doesn’t know what the causes are. It has to guess. Similarly, your brain doesn’t know what’s going on in the outside world. All it’s getting are wavelengths of light, changes in air pressure, concentrations of chemicals, and so on. Again, those are the effects of some set of causes. This is what philosophers call a reverse inference problem. So what is your brain using to solve the reverse inference problem, to guess at the causes of the sense data that will arrive in a moment from now? Past experiences.
As your brain attempts to solve the reverse inference problem, it is not asking itself, figuratively speaking “What is this?” Instead, it is asking something more akin to “What is this like?” “What is this similar to in my past experience?” Your brain is making guesses about what is going to happen next, so it knows how to act next to keep you alive and well. It’s continuously drawing on your past experiences to create your present. The really cool thing about this? It’s really hard for people to change their past. However, by changing your present, you are cultivating a different future. By changing what you do and say, and feel, you are seeding your brain to predict differently in the future.
This gets us into all sorts of knotty questions about responsibility and free will.
The bottom line is we’re more responsible for ourselves than we might think, and, as I discuss in the book, we’re also more responsible for other people that we might think. Or want. You know, sometimes you’re responsible for something not because the situation is your fault—you’re responsible for something because you’re the only person who can change the way things are. It’s not an issue of culpability.The actions and the experiences that your brain makes today become your brain’s predictions for tomorrow. So making an effort to cultivate new experiences and learn new things today is an investment in who you will be tomorrow. Some people have control over many things in their lives, and some people have less control because of their life circumstances, but everyone can control something.
There’s that example in your book of a man who mistakes a shepherd boy holding a herding stick for a guerilla fighter with a rifle and almost shoots him before being stopped. In his subjective reality, which his brain has constructed, he’s taking aim at a militant fighter. In objective reality, he’s taking aim at a kid with some cows. How do we think about holding him accountable?
Well, in this case, responsibility is complicated because he was drafted into the army by the government. But what was true for him is true for all of us: what we see is a combination of what is going on out in the world and inside our own bodies, as well as what is going on inside our heads. I actually wrote about this in The New York Times. To the best of my knowledge, here is what the scientific evidence suggests: It is possible for a person to literally see a gun where there is no gun. So, if the soldier’s brain predicted that another person was holding a gun, and his heart was racing at 180 beats a minute, his brain would have had trouble sampling visual information from the world effectively. And the result would be that his brain would go with his prediction—and he sees a gun—instead of correcting the prediction with visual input of a stick, from the world. Think about what this might mean for the tsunami of problems in policing that we are grappling with right now.
An important consideration here: where do your brain’s predictions come from? Those predictions come from not just your own past experiences, but what you read and what you see in the news and what you watch on television and the social media that you’re exposed to. That’s where your predictions come from—from a world that others curate for you. As you get older, you have some choice in curating that world by what you expose yourself to (and what you don’t). We’re getting into Lesson Seven in the book: we’re social animals and we learn from each other. We don’t just learn by doing, we also learn by telling stories and listening to one another. We communicate our own experiences to other people and other people learn from those experiences. So we don’t have to go through the painful process of learning everything on our own. This social learning has serious benefits, but it also has some risks. This is one aspect of free will that few people talk about: You can broaden your experiences today to predict differently tomorrow. Effective control over your behavior requires that you broaden the horizon of time. Having control of your actions isn’t only about avoiding certain actions “in the heat of the moment”—it’s also about seeding your brain to have more flexibility in constructing your predictions before the heat of the moment.
It’s important to understand what the scientific evidence is regarding how your brain controls your actions. You don’t see stuff in the world and then draw a gun. Based on your brain’s best understanding of how the world is right now, your brain prepares your upcoming actions, like drawing a gun, taking aim, and so on, and that makes it more likely that you will literally see certain things, like a gun, if your brain has learned these associations in the past. That is how your brain works.
Obviously, this is a very anxious time with the election and coronavirus. I’m curious how you see your work in your first book, How Emotions Are Made, intersecting with this stressful moment.
To better understand anxious, stressed feelings, we have to return to your brain’s most important job: to control the systems of your body in an energy efficient way. You can think about energy efficiency like a budget. A financial budget tracks money as it’s earned and spent. A budget for your body similarly tracks resources like water, salt, and glucose as you gain and lose them. Every time your brain has to learn something new is like a withdrawal from your body budget. Actions that replenish your resources, such as eating and sleeping, are like deposits. What is stress? It is when your brain makes a withdrawal from the body budget. Good stress occurs when the withdrawal is followed by a deposit. Chronic stress is when your brain keeps spending and spending, without sufficient deposits, driving the body budget into a deficit. This is a simplified explanation, but it captures the key idea that running a body requires biological resources. Every action you take (or don’t take) is an economic choice—your brain is guessing when to spend resources and when to save them. Ditto for everything you learn (or don’t learn). (The scientific term for body budgeting is allostasis.)
Everything you think, feel, and do is a consequence of your brain’s central mission to keep you alive and well by managing your body budget. We don’t experience our every thought, every feeling of anxiety, happiness or anger or awe, every hug we give or receive, every kindness we extend, and every insult we bear as a deposit or withdrawal in our metabolic budgets, but under the hood, that is what’s happening.
When your brain can’t predict well—when there is too much uncertainty, for example—your brain may attempt to learn something new so that it can predict better next time. Learning involves the release of a whole set of chemicals, some of which are related to making you feel jittery and on edge. In the short term, learning is a good investment of energy, because it’s likely to pay dividends in the future. The key is to replenish what you’ve spent, to keep your body budget solvent.
If the uncertainty goes on for too long maybe because of COVID fears, or economic uncertainty—if your body budget is being drained—you may end up running a deficit, which leaves you feeling constantly worked up and unpleasant. In our culture, we have learned to make sense of these feelings as anxiety. Making sense of uncomfortable, heightened arousal as anxiety might lead us to act in ways that only further burden our body budgets, rather than trying to pay down the debt by getting enough sleep, eating healthfully, giving and receiving support to loved ones, and so on. Eventually, this can sometimes lead to bigger problems. I mean, what do you do when your actual bank account is running a deficit?
Right. What does that mean for a brain? It means that you stop moving your body as much and you stop learning. Think about the current social moment. Why does it feel better for people to surround themselves with other like-minded people in an echo chamber? Social media may help construct that chamber, but that’s not the whole story. Why don’t more people forage for novel information that does not conform to their beliefs? Perhaps because it’s metabolically expensive. And when your body budget’s already encumbered because you’re not sleeping enough or because there’s tremendous amount of economic uncertainty, or you’re worried about not being able to feed your kids, or you’re worried about getting sick… You end up making lots of little withdrawals over time that are not made up by deposits—it’s like paying lots of little taxes that add up over time. And eventually, you could get a point where you are swimming in a sea of uncertainty or surfing a tsunami of stress. Persistent uncertainty is very, very hard on a human nervous system.
How does the idea of “emotional granularity” offset that? This idea that if we understand our world through the concepts that we have, then the more concepts we have, the better we can understand what we’re feeling.
An emotion is an episode in which your brain uses what you know about emotion – emotion concepts – to make sense of the changes in your body (changes in heart rate, in breathing, and so on) by connecting these sense data and the feelings that they give rise to with what is going on around you in the world. This is how you might come to experience a tightness in your chest as anxiety, determination, or the physical symptoms of a respiratory infection. The more concepts you know, the more flexibly your brain can guess at might cause the sense data from your body in a given situation.
Concepts help you understand emotions after they have emerged, sure, but they are also a key ingredient of constructing emotions in the first place. Emotions don’t happen to you—they are made by your brain as you need them. They are not built into your brain at birth. They are built by your brain using the emotion concepts that you have learned. Using emotion concepts, your brain runs your body budget by predicting the causes of upcoming events in your body in a way that is linked to the situation that you are in, for the purposes of acting in a particular way. So ultimately, concepts are tools for making emotion. More generally, concepts are tools for making new meaning of the physical sensations from your body, in the context that you’re in, to guide your actions in a particular way. And the result is sometimes an emotion. So emotional granularity doesn’t mean that you just understand your emotions better. It means that you construct your emotions more precisely to fit the situation that you are in.
How does that change our experience of the world then? For example, if I were to say, “I’m not sad, I’m disappointed.”
To answer your question, we have to talk about affect. Your brain is constantly managing your body budget, and your body is constantly sending back sense data to your brain. This is happening right now, even though you are probably unaware of it. And that’s because you are not wired to consciously experience this continuous symphony of sense data. Evolution has given you a workaround, though: simple feelings of comfort or pleasantness, discomfort or unpleasantness, feeling wound up or tired. These simple feelings you might call mood. Scientists call them affect.
Let’s say you’re running a body budget deficit. So you feel crappy. Let’s say you’re not a very granular person and, for you, anger, sadness, fear are all synonyms of, “I feel like shit.” Well, what should you do next to deal with the situation? Your brain hasn’t made a very specific guess. Do you have a drink of water? Do you yell at someone? Do you go for a run? It’s hard to know because your brain hasn’t made a concept that allows it to predict a specific action.
But if your brain has learned that sadness means you have lost something dear to you, whereas disappointment means that your hopes or expectations have been dashed—that is, when you have learned that sadness and disappointment are not synonyms, but are distinct concepts involving distinct actions—then making your affect meaningful with a concept for sadness will lead to very different actions than if your brain makes a concept for disappointment.
Here’s a trivial example: like many people in this country, I am weary and I am stressed. Under the hood, my brain is constructing concepts to predict and make sense of what is going on inside my body in relation to the situation I am in. My brain could construct an experience of anxiety, or depression, or hopelessness. But instead, it constructs a concept of an encumbered body budget. And this guides my actions. I need to make sure that I sleep and I need to make sure that I drink enough water. I need to make sure that I exercise, even though I really don’t feel like it. I make sure to get enough social contact with those I love.
Emotional granularity is also knowing when not to make an emotion. Instead, my brain is making meaning of the sense data, and the affective feelings that they cause, as a physical phenomenon. And what does this granularity buy you? It buys you the flexibility to make sense of your sensations and act on them differently depending on the context, tailoring your actions to the situation you are in.
This interview has been edited and condensed.