How Emotions Are Made: The Secret Life of the Brain

by Lisa Feldman Barrett

The interoceptive network encompasses two networks commonly known as the salience network and the default mode network.

The two parts of your interoceptive network participate in a prediction loop.

To manage all of this spending and replenishing, your brain must constantly predict your body’s energy needs, like a budget for your body. Just as a company has a finance department that tracks deposits and withdrawals and moves money between accounts, so its overall budget stays in balance, your brain has circuitry that is largely responsible for your body budget. That circuitry is within your interoceptive network. Your body-budgeting regions make predictions to estimate the resources to keep you alive and flourishing, using past experience as a guide.28

Why is this relevant to emotion? Because every brain region that’s claimed to be a home of emotion in humans is a body-budgeting region within the interoceptive network. These regions, however, don’t react in emotion. They don’t react at all. They predict, intrinsically, to regulate your body budget. They issue predictions for sights, sounds, thoughts, memories, imagination, and, yes, emotions. The idea of an emotional brain region is an illusion caused by the outdated belief in a reactive brain.

Someone merely walks toward you while you are standing still, and your brain predicts that you need fuel! In this manner, any event that significantly impacts your body budget becomes personally meaningful to you.

We ask volunteers to sit completely motionless in front of a computer screen and view pictures of animals, flowers, babies, food, money, guns, surfers, skydivers, car crashes, and other objects and scenes. These pictures impact their body budget; heart rates go up, blood pressures change, blood vessels dilate. These budgetary changes, which prepare the body to fight or flee, occur even though the volunteers are not moving and have no conscious plan to move.

As it turns out, people spend at least half their waking hours simulating rather than paying attention to the world around them, and this pure simulation strongly drives their feelings.33

Other people regulate your body budget too. When you interact with your friends, parents, children, lovers, teammates, therapist, or other close companions, you and they synchronize breathing, heart beats, and other physical signals, leading to tangible benefits. Holding hands with loved ones, or even keeping their photo on your desk at work, reduces activation in your body-budgeting regions and makes you less bothered by pain.

Affect is the general sense of feeling that you experience throughout each day. It is not emotion but a much simpler feeling with two features. The first is how pleasant or unpleasant you feel, which scientists call valence. The pleasantness of the sun on your skin, the deliciousness of your favorite food, and the discomfort of a stomachache or a pinch are all examples of affective valence. The second feature of affect is how calm or agitated you feel, which is called arousal.

Let’s be clear on one thing: interoception is not a mechanism dedicated to manufacturing affect. Interoception is a fundamental feature of the human nervous system, and why you experience these sensations as affect is one of the great mysteries of science. Interoception did not evolve for you to have feelings but to regulate your body budget.

Your affective feelings of pleasure and displeasure, and calmness and agitation, are simple summaries of your budgetary state. Are you flush? Are you overdrawn? Do you need a deposit, and if so, how desperately?39

prompts your brain to search for explanations. Your brain constantly uses past experience to predict which objects and events will impact your body budget, changing your affect. These objects and events are collectively your affective niche.

Right now, this book is within your affective niche, as are the letters of the alphabet, the ideas you’re reading about, any memories that my words bring to mind, the air temperature around you, and any objects, people, and events from your past that impacted your body budget in a similar situation.

psychologist James A. Russell developed a way of tracking affect, and it’s become popular among clinicians, teachers, and scientists. He showed that you can describe your affect in the moment as a single point on a two-dimensional space called a circumplex, a circular structure with two dimensions, as in figure 4-5. Russell’s two dimensions represent valence and arousal, with distance from the origin representing intensity.

When you experience affect without knowing the cause, you are more likely to treat affect as information about the world, rather than your experience of the world.

This phenomenon is called affective realism, because we experience supposed facts about the world that are created in part by our feelings. For example, people report more happiness and life satisfaction on sunny days, but only when they are not explicitly asked about the weather.

But these images do not have affective properties inside them. The phrase “an unpleasant image” is really shorthand for “an image that impacts my body budget, producing sensations that I experience as unpleasant.”

The thing is, a bad feeling doesn’t always mean something is wrong. It just means you’re taxing your body budget. When people exercise to the point of labored breathing, for example, they feel tired and crappy well before they run out of energy. When people solve math problems and perform difficult feats of memory, they can feel hopeless and miserable, even when they are performing well.

People like to say that seeing is believing, but affective realism demonstrates that believing is seeing.

Now consider the third possibility: there is no snake, and you don’t see a snake. In this case, your visual predictions of a snake are corrected quickly; however, your interoceptive predictions are not. Your body-budgeting regions keep predicting adjustments to your budget long after the predicted need is over. You therefore may take a long time to calm down, even if you know there is nothing wrong. Remember when I compared your brain to a scientist who makes and tests hypotheses? Your body-budgeting regions are like a mostly deaf scientist: they make predictions but have a hard time listening to the incoming evidence.51

Take a moment and consider what this means for your day-to-day life. You’ve just learned that the sensations you feel from your body don’t always reflect the actual state of your body. That’s because familiar sensations like your heart beating in your chest, your lungs filling with air, and, most of all, the general pleasant, unpleasant, aroused, and quiescent sensations of affect are not really coming from inside your body. They are driven by simulations in your interoceptive network.53

In short, you feel what your brain believes. Affect primarily comes from prediction.

Interoception in the moment is more influential to perception, and how you act, than the outside world is.

Our new knowledge of brain anatomy now compels us to go one step further. Affect is not just necessary for wisdom; it’s also irrevocably woven into the fabric of every decision.58

So how do brains evolve? They reorganize as they expand, like companies do, to keep themselves efficient and nimble.61

From the perspective of your brain, anything in your affective niche could potentially influence your body budget, and nothing else in the universe matters. That means, in effect, that you construct the environment in which you live.

You construct your environment—your reality—by virtue of what sensory input from the physical environment your brain selects; it admits some as information and ignores some as noise. And this selection is intimately linked to interoception. Your brain expands its predictive repertoire to include anything that might impact your body budget, in order to meet your body’s metabolic demands. This is why affect is a property of consciousness.

An incredible 50 percent of the words we hear cannot be understood out of context (when presented in isolation). But using your concepts, your brain learns to categorize, constructing phonemes in tens of milliseconds within all this variable, noisy information, ultimately permitting you to communicate with others.3

And yet, you did not experience blurry streaks across your visual field. That’s because you don’t see the world in terms of pixels: you see objects, and they changed very little as you moved your eyes. You perceive low-level regularities like lines, contours, streaks, and blurs, as well as higher-level regularities like complex objects and scenes. Your brain learned these regularities as concepts long ago, and it uses those concepts now to categorize your continually changing visual input.4

Your perceptions are so vivid and immediate that they compel you to believe that you experience the world as it is, when you actually experience a world of your own construction.

My point is not to say, “You construct instances of emotion by categorization: isn’t that unique?” Rather, it’s to show that categorization constructs every perception, thought, memory, and other mental event that you experience, so of course you construct instances of emotion in the same manner. This is not effortful, conscious categorization, as when an entomologist pores over some new specimen of weevil, deciding whether it’s a member of the anthribidae or nemonychidae family. I’m speaking of the rapid, automatic categorization performed constantly by your brain, in every waking moment, in milliseconds, to predict and explain the sensory input that you encounter. Categorization is business as usual for your brain, and it explains how emotions are made without needing fingerprints.

Philosophers and scientists define a category as a collection of objects, events, or actions that are grouped together as equivalent for some purpose. They define a concept as a mental representation of a category.

This classical view of concepts assumes that their corresponding categories have firm boundaries. Instances of the category “Bee” are never in the category “Bird.” Also in this view, every instance is an equivalently good representative of the category. Any bee is representative, so it goes, because all bees have something in common, either the way they look or what they do, or an underlying fingerprint that makes them bees. Any variation from bee to bee is considered irrelevant to the fact that they are bees. You might notice a parallel here to the classical view of emotion, in which every instance of the category “Fear” is similar, and instances of “Fear” are distinct from instances of “Anger.”9

From the ashes of classical concepts, a new view arose. It said that a concept is represented in the brain as the best example of its category, known as the prototype. For example, the prototypical bird has feathers and wings and can fly. Not all instances of “Bird” have these features, such as ostriches and emus, but they are still birds. Variation from the prototype is perfectly fine, but not too much variation: a bee is still not a bird, even though it has wings and can fly.

If there are no emotion prototypes stored in the brain, how do people list their features so easily? Most likely, your brain constructs prototypes as you need them, on the spot. You have experienced a diverse population of instances of the concept “Sadness,” which reside in bits and pieces in your head, and in the blink of an eye, your brain constructs a summary of sadness that best fits the situation. (An example of population thinking in the brain.)14

Thus, concepts aren’t fixed definitions in your brain, and they’re not prototypes of the most typical or frequent instances. Instead, your brain has many instances—of cars, of dot patterns, of sadness, or anything else—and it imposes similarities between them, in the moment, according to your goal in a given situation. For example, your usual goal for a vehicle is to use it for transportation, so if an object meets that goal for you, then it’s a vehicle, whether it’s a car, a helicopter, or a sheet of plywood with four wheels nailed on. This explanation of concepts comes from Lawrence W. Barsalou, one of the world’s leading cognitive scientists studying concepts and categories.16

Goal-based concepts are super flexible and adaptable to the situation. If you’re in a pet shop to replenish your home aquarium and the salesperson asks, “What kind of fish would you like?” you might say “a goldfish” or “a black molly” but probably not “a poached salmon.” Your concept “Fish” in this situation serves a goal to purchase a pet, not to order dinner, so you’ll construct instances of the concept “Fish” that best suit your fish tank. If you’re on a snorkeling expedition, you will use “Fish” in service of a goal to find exciting wildlife, so the best instance might be a huge nurse shark or a colorful spotted boxfish. Concepts are not static but remarkably malleable and context-dependent, because your goals can change to fit the situation.

To see the real power of goal-based concepts, consider a purely mental concept such as “Things That Can Protect You from Stinging Insects.” Instances of the category are remarkably diverse: a flyswatter, a beekeeper’s suit, a house, a Maserati, a large trash can, a vacation in Antarctica, a calm demeanor, even a university degree in entomology. They share no perceptual features. This category is clearly and entirely a construction of the human mind.

In fact, the goal is the only thing that holds together the category.

When you categorize, you might feel like you’re merely observing the world and finding similarities in objects and events, but that cannot be the case. Purely mental, goal-based concepts such as “Things That Can Protect You from Stinging Insects” reveal that categorization cannot be so simple and static.

Your experience it based on your goal.

So, what’s happening in your brain when you categorize? You are not finding similarities in the world but creating them. When your brain needs a concept, it constructs one on the fly, mixing and matching from a population of instances from your past experience, to best fit your goals in a particular situation. And herein lies a key to understanding how emotions are made.17

Using this storm of predictions, your brain makes meaning of sensations based on your past experiences with airports and friends and illnesses and related situations. Your brain weighs its predictions based on probabilities; they compete to explain what caused your sensations, and they determine what you perceive, how you act, and what you feel in this situation. Ultimately, the most probable predictions become your perception: say, you are happy and your friend is walking through the gates right now.

On the other hand, if you constructed some other instance of “Fear,” such as the exuberant fear of riding a rollercoaster, you might have trouble understanding why your friend was so upset by the flight. Successful communication requires that you and your friend are using synchronized concepts.

Their competition in your brain is like Darwin’s theory of natural selection but carried out in milliseconds; the most suitable instances outlive all rivals to fit your goal in the moment. That is categorization.18

The newborn brain has the ability to learn patterns, a process called statistical learning. The moment that you burst into this strange new world as a baby, you were bombarded with noisy, ambiguous signals from the world and from your body. This barrage of sensory input was not random: it had some structure. Regularities. Your little brain began computing probabilities of which sights, sounds, smells, touches, tastes, and interoceptive sensations go together and which don’t. “Those edges form a boundary. Those two blobs are part of a bigger blob. That brief silence was a separator.” Little by little, but with surprising speed, your brain learned to resolve this ocean of vague sensation into patterns: sights and sounds, smells and tastes, touches and interoceptive sensations, and combinations thereof.19

Spoken words give the infant brain access to information that can’t be found by observing the world and resides only in the minds of other people, namely, mental similarities: goals, intentions, preferences.

This is a remarkable feat for infants because they used the sounds of a word to predict whether objects made the same noise or not, learning a pattern that transcended mere physical appearance. Words encourage infants to form goal-based concepts by inspiring them to represent things as equivalent. In fact, studies show that infants can more easily learn a goal-based concept, given a word, than a concept defined by physical similarity without a word.31

Any animal can view a bunch of similar-looking objects and form a concept of them. But you can show human infants a bunch of objects that look different, sound different, and feel different, and merely add a word—a WORD—and these little babies form a concept that overcomes the physical differences. They understand that the objects have some kind of psychological similarity that can’t be immediately perceived through the five senses. This similarity is what we called the goal of the concept. The infant creates a new piece of reality, a thing called a “wug” with the goal “to make a ringing noise.”

The emotional information is in your perception. Nature provided your brain with the raw materials to wire itself with a conceptual system, with input from a chorus of helpful adults who spoke emotion words to you in a deliberate and intentional way.