How Emotions Are Made: The Secret Life of the Brain

by Lisa Feldman Barrett

The eighteenth-century philosopher Jeremy Bentham thought that an animal belongs in the human moral circle only if we can prove the animal can feel pleasure or pain. I disagree. An animal is worthy of inclusion in our moral circle if there is any possibility at all that it can feel pain. Does that keep me from killing a fly? No, but I’ll make it quick.

An interoceptive network, along with the affective niche it helps create, is not sufficient for feeling and perceiving emotions. For that, a brain must also be equipped to build a conceptual system, to construct emotion concepts, and to make sensations meaningful as emotions in themselves and others. A hypothetical macaque with the capacity for emotions must be able to look at another macaque swinging in a tree and see not only the physical movement but an instance of “Joy.”

Sheep apparently recognize one another by face (!), and goats by vocal bleats.

Baboons can learn to distinguish a “B” from a “3” regardless of font, and macaques can distinguish animal images from food images.

Macaques can even learn concepts to distinguish painting styles by Claude Monet, Vincent van Gogh, and Salvador Dalí.

The concepts that animals learn will not be the same as human concepts, however. Humans construct goal-based concepts, and a macaque brain simply lacks the necessary wiring to do so.

Chimpanzees, our genetically closest cousins, have larger brains than macaques do, with more of the wiring necessary for integrating sensory information. A human brain is still three times as large as a chimp brain, though, with more of this critical wiring.

That doesn’t rule out goal-based concepts for chimps. It’s just likely that your brain is better equipped to create purely mental concepts, such as “Wealth,” whereas a chimpanzee brain is better equipped to create concepts for actions and concrete objects, like “Eating” and “Gathering” and “Banana.”

The big question is, can one chimp watch another chimp swinging in a tree and perceive an instance of “Joy”? That would require the observing chimp to have a purely mental concept and infer the swinging chimp’s intention, making a mental inference. Most scientists assume that mental inference is a core ability of the human mind. So a lot is at stake if apes can do it. We know that monkeys cannot; they can understand what a human is doing but not what he is thinking, desiring, or feeling.

Chimps might have the prerequisites because they can create some mental similarities amid perceptual differences. For instance, they know that leopards climb trees, snakes climb trees, and monkeys climb trees. It’s conceivable that chimps could extend this concept to a new animal who can perform a similar action, such as a housecat, and predict that the cat will climb a tree. But a human concept “To Climb” is more than just an action; it’s a goal. So the real test would be whether chimps would understand that a person running up a flight of stairs, ambling up a ladder, and crawling up a rock face all share the goal “To Climb.” That mental feat would show us that chimps really can go beyond physical similarities, grouping together instances of climbing that look very different but have a shared mental goal. And if chimps could comprehend that moving up a social hierarchy is also climbing, then their concepts would be identical to our own.

it appears that chimps can categorize dissimilar-looking objects according to their function—tools, containers, food—if you reward them, and if they already have firsthand experience with the function.

Skeptics point out that apes certainly don’t use symbols or words to talk about the weather or their children; they can refer to something other than a reward, but only if a reward is waiting at the other end. (It would be interesting to observe what would happen to symbol-trained apes if their trainers stopped rewarding them. Would they continue to use the symbols?) The important point, I think, is that words don’t seem to be intrinsically part of most apes’ affective niche, as they are for typical human babies. To apes, words alone are not worth learning.

Chimps, in contrast to bonobos, have been characterized as charming, clever creatures with a dark side. They hunt and kill each other opportunistically to take over territory or get food. They also attack strangers for no reason, maintain a rigid dominance hierarchy, and beat females into sexual submission. Bonobos would rather work out their conflicts by having sex. That’s a much better alternative than genocide.

At present, however, we have no firm evidence that chimps can form goal-based concepts. They cannot imagine something completely novel, like a flying leopard, even though they and macaques have a network that’s analogous to the human default mode network (part of the interoceptive network). They cannot consider the same situation from different points of view. They can’t imagine a future that is different from the present. They also do not realize that goal-based information resides inside the heads of other creatures. That’s why chimps and other great apes most likely cannot create goal-based concepts.

Any concept can be goal-based—recall that “Fish” can be a pet or a dinner—but emotion concepts are only goal-based, so it seems very likely that chimps cannot learn emotion concepts like “Happiness” and “Anger.” Even if they can learn an emotion word like “angry,” it’s not clear that they can understand it or use it in a goal-based way, like categorizing another creature’s actions as anger.

If chimps cannot form goal-based concepts, then necessarily, chimps are not naturally equipped to teach concepts to one another; that is, they don’t have social reality. Even if they could learn a concept like “Anger” from a human trainer, one generation doesn’t create the context for the next generation to bootstrap concepts into their brains. Chimps and other primates do have shared practices, like cracking nuts with rocks, but chimp mothers don’t spontaneously instruct their infants on the finer culinary points; the children learn by observation.

We can regulate a dog’s body budget, and dogs can regulate ours in turn. (I wouldn’t be surprised if dogs and their human owners even synchronize their heart rates, the way close humans do for each other.) We also probably selected for dogs with eyes that we perceive as expressive and facial muscles that move easily to serve as a canvas upon which we can paint complex mental states. We love dogs so much that we bred them to love us back, or at least to see them as loving us.

Dogs, like other mammals, feel affect. No big surprise here. One way they appear to express affect is by wagging their tails. They apparently make larger tail-wagging movements to the right during pleasant events, such as seeing their owner, and to the left for unpleasant events, such as seeing an unfamiliar dog. The choice of side has been associated with brain activity: wagging to the right is said to mean relatively greater activity on the left side of the brain, and vice versa.

Dogs also appear to look at each other’s tails to perceive affect. They’re more relaxed when they view movies of right-wagging tails and more stressed for left-wagging tails, as measured by heart rate and other factors. Dogs also appear to perceive affect in the faces and voices of humans.

Dogs can learn concepts too. Again, not surprising. They can distinguish dogs from other animals in photographs, for example, if trained to do so.

Dogs also form olfactory concepts. They can distinguish the smell of an individual human, grouping together different smells from different parts of the body to treat as equivalent, and yet distinct from the smells of other humans. And of course, we know that dogs can be trained to track categories of objects by smell. Anyone who’s been caught in an airport with food or drugs in their suitcase can tell you so.

dogs appear to infer intentions of some sort. Dogs are better than chimps at perceiving human gestures and following human gaze.

In each trial, a dog owner offered his or her dog a desirable biscuit, then explicitly instructed the dog not to eat it and promptly left the room. Unbeknownst to the owner, however, an experimenter then entered the room and influenced the dog’s behavior, either handing the treat to the dog (who ate it) or removing the treat from the room. Afterward, the experimenter either told the owner the truth or lied. Half the owners were told that their dog had obeyed and to greet their dog in a warm and friendly manner; the rest heard that the dog had eaten the biscuit and should be scolded. This created four different scenarios: obedient dog with a friendly owner, obedient dog being scolded, disobedient dog with a friendly owner, and disobedient dog being scolded. What happened? The scolded dogs performed more behaviors that people perceive as stereotypically guilty, regardless of whether or not the dogs had disobeyed. This is evidence that dogs were not experiencing guilt at performing a forbidden act; rather, their owners were perceiving guilt when they believed the dog had eaten the biscuit.

Scientists are still exploring the limits of what dogs can do, emotionally speaking. Their affective niche is broader than ours in some respects, because their senses of smell and hearing are superior; but their affective niche is narrower in other respects, because they can’t travel into the future to imagine a world other than the present one.

My view, from evaluating the evidence, is that dogs don’t have human emotion concepts like anger, guilt, and jealousy. It’s conceivable that one individual dog could develop some emotion-like concept of its own, different from any human emotion concept, in relation to its owner. Without language, however, the dog’s emotion concept would necessarily be narrower than a human’s, and it couldn’t teach the concept to other dogs.

Even if dogs don’t share human emotions, it’s remarkable just how much dogs and other animals can accomplish through affect alone. Many animals can experience unpleasant affect when another animal nearby is suffering. The first animal’s body budget is taxed by the second animal’s discomfort, so the first animal tries to fix the situation.* Even a rat will help another rat who is in distress, for example. Human infants can comfort another infant who is in distress. You don’t need emotion concepts for this ability, just a nervous system with interoception that produces affect.

Do animals regulate their body budgets by interoception? I cannot speak for the entire animal kingdom here but for mammals—rats, monkeys, apes, dogs—I think we are on pretty safe ground answering yes. Do animals experience affect? Again, I think we can give a pretty confident yes, based on some biological and behavioral clues. Can animals learn concepts and can they categorize predictively with those concepts? Definitely. Can they learn action-based concepts? Unquestionably yes. Can they learn the meaning of words? Under some circumstances, some animals can learn words or other symbol systems, in the sense that the symbols become part of the statistical patterns that a brain can capture and store for later use.

But can animals use words to go beyond the statistical regularities in the world, to create goal-based similarities that unite actions or objects that look, sound, or feel different? Can they use words as invitations to form mental concepts? Do they realize that part of the information they need about the world resides in the minds of other creatures around them? Can they categorize actions and make them meaningful as mental events? Probably not.

From the perspective of the theory of constructed emotion, the question “Is a growling dog angry?” is the wrong question to ask in the first place, or at least incomplete. It assumes that a dog is measurably angry or not angry in some objective sense.

But as you’ve learned, emotion categories have no consistent, biological fingerprints. Emotions are always constructed from some perceiver’s point of view. So the question “Was Rowdy angry?” is actually two separate scientific questions: “Was Rowdy angry from the boy’s perspective?” “Was Rowdy angry from his own perspective?”

Now let’s consider the second question, regarding Rowdy’s experience. Did he feel anger when he growled? Was he able to construct an experience of anger from his sensory predictions? The answer is almost certainly no. Dogs do not have the human emotion concepts necessary to construct an instance of anger. Lacking a Western concept of “Anger,” dogs cannot categorize their interoceptive and other sensory information to create an instance of emotion. Nor can they perceive emotion in other dogs or in humans. Dogs do perceive distress and pleasure and a handful of other states, a feat that requires only affect.

Dogs may well have some emotion-like concepts. For example, a number of scientists now suspect that very social animals, such as dogs and elephants, have some concept of death and can experience some kind of grief. This grief need not have exactly the same features as human grief, but both could be rooted in something similar: the neurochemical basis of attachment, body budgeting, and affect. In humans, the loss of a parent, lover, or close friend can wreak havoc with your budget and cause much distress that operates similarly to drug withdrawal. When one creature loses another who helped to keep its body budget on track, the first creature will feel miserable from the budget imbalance.

Construction views of emotion are frequently misinterpreted as saying “dogs don’t have emotions” (and sometimes even “people don’t have emotions”). Such simplistic statements are meaningless because they assume emotions have essences so that they can exist, or not, independent of any perceiver. But emotions are perceptions, and every perception requires a perceiver. And therefore every question about an instance of emotion must be asked from a particular point of view.

We are accustomed to thinking about animals in terms of ourselves: how similar they are to us, what they teach us about ourselves, how they might be useful to us, how we are superior to them. It’s okay for us to anthropomorphize animals if it’s going to protect them. But when we see animals through the lens of our own identity, we can harm them in ways that we often don’t think about. We treat anxiously attached dogs as “too dominant” and punish them when we should be offering them predictable care and affection. We rip baby chimps from their mothers when in the wild they would nurse until they are five years old, secure in the warmth and smell of their mother’s fur. Our challenge is to understand animal minds for their own sake, not as inferior human minds.

Animals are emotional creatures, at least as far as human perceivers are concerned. This is part of the social reality that we create. We grant emotions to our cars, our houseplants, and even little circles and triangles in a movie. We also grant emotions to animals. However, this does not mean that animals experience emotion. Animals with a small affective niche cannot form emotion concepts. A lion cannot hate a zebra when she hunts and kills it as prey. That is why we don’t find the lion’s actions immoral.

You do have survival circuits for behaviors like the famous “four F’s” (fighting, fleeing, feeding, and mating); they’re controlled by body-budgeting regions in your interoceptive network, and they cause bodily changes that you experience as affect, but they are not dedicated to emotion. For emotion, you also need emotion concepts for categorization.

The human brain is a master of deception. It creates experiences and directs actions with a magician’s skill, never revealing how it does so, all the while giving us a false sense of confidence that its products—our day-to-day experiences—reveal its inner workings.

from one moment to another, your billions of neurons continually reconfigure themselves from one pattern into another. Chemicals called neurotransmitters make this possible. They enable signals to pass between neurons, and they dial up or dial down neural connections in a split second, so information flows along different paths.

Microwiring. Neurotransmitters. Plasticity. Degeneracy. Multipurpose circuitry. Neuroscientists sum up this incredible well of variation by calling the brain a “complex system.”

Complexity is a metric to describe any structure that efficiently creates and transmits information. A system with high complexity can create many new patterns by combining bits and pieces of old patterns. You can find complex systems in neuroscience, physics, mathematics, economics, and other scholarly disciplines.

A brain with high complexity and degeneracy brings distinct advantages. It can create and carry more information. It’s more robust and reliable, with multiple paths to get to the same end. It’s more resistant to injury and illness;

Natural selection favors a complex brain. Complexity, not rationality, makes it possible for you to be an architect of your experience. Your genes allow you, and others, to remodel your brain and therefore your mind.

A human brain can create many kinds of minds, yet all human minds do have some common ingredients. For millennia, scholars believed that the inevitable bits of the mind were essences, but they are not. The ingredients are three aspects of the mind that we’ve encountered in this book: affective realism, concepts, and social reality.

Affective realism, the phenomenon that you experience what you believe, is inevitable because of your wiring.

Body-budget predictions laden with affect, not logic and reason, are the main drivers of your experience and behavior. We all think a food “is delicious” as if the flavor were embedded in the food, when flavor is a construction and the deliciousness is our own affect. When a soldier in a warzone perceives a gun in someone’s hands when no gun is present, he might actually see that gun; it’s not a mistake but a genuine perception. Judges who are hungry during parole hearings render more negative decisions.

Firestein opens Ignorance with an old proverb, “It is very difficult to find a black cat in a dark room, especially when there is no cat.”

Stuart Firestein

this same superpower that makes us effective civilization-builders also impedes our own understanding of how we do it. We constantly mistake perceiver-dependent concepts—flowers, weeds, colors, money, race, facial expressions, and so on—for perceiver-independent reality. Many concepts that people consider to be purely physical are in fact beliefs about the physical, such as emotions, and many that appear to be biological are actually social.

I don’t know about you, but I find some comfort in a bit of uncertainty. It’s refreshing to question the concepts that have been given to us, and to be curious about which are physical and which are social. There is a kind of freedom in realizing that we categorize to create meaning, and therefore it is possible to change meaning by recategorizing. Uncertainty means that things can be other than they appear. This realization brings hope in difficult times and can prompt gratitude in good times.

We’re finding that neurons aren’t the only important cells in the brain; glial cells, long ignored, turn out to do a hell of a lot, possibly even communicating with each other without synapses. The enteric nervous system, which controls your stomach and intestines, is looking more and more important for understanding the mind, but it’s extremely difficult to measure and therefore largely unexplored. We’re even finding that microbes in your stomach have a huge effect on mental states, and nobody knows how or why.

The most important type of brain cell for our discussion is the neuron. There are a wide variety of neurons, but in general, each one consists of a cell body, some branch-like structures on the top called dendrites, and one root-like structure on the bottom called an axon, which has axon terminals at its end,