This is one of those rare books that after reading you will never look at the world or yourself in the same way again. It starts with a simple supposition. “People vary tremendously in how they differentiate their emotional experiences.” Not only that, but how we interpret the emotional cues we see in others is extremely varied. After all, “the human face is laced with forty-two small muscles on each side.” The prevailing view has been that humans have emotional fingerprints, innately transmitted, unquestionably identifiable, and little effected by culture. “If people move the same facial muscles in the same pattern each time they experience a given emotion- scowling in anger, smiling in happiness, pouting in sadness, and so on- and only when they experience that emotion, then the movements might be a fingerprint.” It turns out this view is wrong. In rigorous academic study after study it has simply not held up to testing. Instead, we take many emotional facial cues from context and work backwards to the supposed emotion the face represented. Furthermore, “emotion is not a thing but a category of instances, and any emotion category has tremendous variety” both between individuals and within the same individual, dependent on time and circumstance. There is no thing as an average anger pattern. The idea that certain emotions “reside” in certain parts of the brain has also been thrown into doubt. Despite widespread belief that fear resides in the amygdala, recent twin studies have described “identical twins, with identical DNA, suffering from identical brain damage, living in highly similar environments, but one has some fear-related deficits while the other has none…. They point instead to the idea that the brain must have multiple ways of creating fear, and therefore the emotion category “Fear” cannot be necessarily localized to a specific region…. Brain regions like the amygdala are routinely important to emotion, but they are neither necessary nor sufficient for emotion…. A mental event, such as fear, is not created by only one set of neurons. Instead, combinations of different neurons can create instances of fear. Neuroscientists call this principle degeneracy. Degeneracy means “many to one”: many combinations of neurons can produce the same outcome…. The amygdala, for example did show consistent increase in activity for studies of fear, more than you’d expect by chance, but only in a quarter of fear experience studies and about 40 percent of fear perception studies. These numbers fall short of what you’d expect for a neural fingerprint. Not only that, but the amygdala also showed a consistent increase during studies of anger, disgust, sadness, and happiness, indicating that whatever functions the amygdala was performing in some instances of fear, it was also performing those functions during some instances of those other emotions.” Some have suggested that amygdala activity increases when exposed to anything novel, but even that is not certain and with far from the type of regularity to call anything an emotional fingerprint. It is certain that “emotions arise from firing neurons, but no neurons are exclusively dedicated to emotion.”
Barrett suggests that all emotions are mental constructions. “Your past experiences- from direct encounters, from photos, from movies, and books- give meaning to your present sensations. Additionally, the entire process of construction is invisible to you. No matter how hard you try, you cannot observe yourself or experience yourself constructing the image….Your brain uses your past experiences to construct a hypothesis- the simulation- and compares it to the cacophony arriving from your senses. In this manner, simulation lets your brain impose meaning on the noise, selecting what’s relevant and ignoring the rest…. Your concepts are a primary tool for your brain to guess the meaning of incoming sensory inputs…. Concepts also give meaning to the chemicals that create tastes and smells. If I served you pink ice cream, you might expect (simulate) the taste of strawberry, but if it tasted like fish, you would find it jarring, perhaps even disgusting. If I instead introduced it as “chilled salmon mousse” to give your brain fair warning, you might find the same taste delicious (assuming you enjoy salmon). You might think of food as existing in the physical world, but in fact the concept “Food” is heavily cultural.” Similarly, your brain creates emotion. “An emotion is your brain’s creation of what your bodily sensations mean, in relation to what is going on around you in the world…. Emotions are not reactions to the world. You are not a passive receiver of sensory input but an active constructor of your emotions. From sensory input and past experience, your brain constructs meaning and prescribes action. If you didn’t have concepts that represent your past experience, all your sensory inputs would just be noise…. Your familiar emotion concepts are built-in only because you grew up in a particular social context where those emotion concepts are meaningful and useful.” For instance, “heart rate changes are inevitable, their emotional meaning is not…. A physical event like a change in heart rate, blood pressure, or respiration becomes an emotional experience only when we, with emotion concepts that we have learned from our culture, imbue the sensations with additional functions by social agreement.” Similarly, “an instance of fear cannot be reduced to mere ingredients. Fear is not a bodily pattern- just as bread is not flour- but emerges from the interactions of core systems. An instance of fear has irreducible, emergent properties not found in the ingredients alone…. You cannot reverse-engineer a recipe for an instance of fear from a feeling of fear.” Your past helps you create emotions by giving context to new inputs. “Emotions are not, in principle, distinct from cognitions and perceptions…. Your brain’s interconnections are not inevitable consequences of your genes alone. We know today that experience is a contributing factor. Your genes turn on and off in different contexts, including genes that shape your brain’s wiring. (Scientists call this phenomenon plasticity.) That means some of your synapses literally come into existence because other people talked to you or treated you in a certain way.” There are no universal emotions. “You depend on emotion concepts each time you experience another person as emotional.” In real life we see people’s faces in context of their bodies, their voices, and their surroundings. These details help cue the brain along with your preconceived concepts.
Emotion is a form of prediction. Prediction is a primary function of the human brain. “Predictions not only anticipate sensory input from outside the skull but explain it…. Every brain region that’s claimed to be a home of emotions in humans is a body-budgeting region within the interoceptive network. [Interoception is your brain’s representation of all the sensations from your internal organs and tissues, the hormones in your blood, and your immune system.] These regions, however, don’t react to 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.” For example, “when your brain predicts your body will need a quick burst of energy, these regions instruct the adrenal gland in your kidneys to release the hormone cortisol.” Internal predictions create the meaning to outside events. “Other people regulate your body budget too. When you interact with 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.” If emotion is not innate, what is? “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 second feature of affect is how calm or agitated you feel, which is called arousal…. Affect…. depends on interoception. That means affect is a constant current throughout your life, even when you are completely still or asleep. It does not turn on and off in response to events you experience as emotional. In this sense, affect is a fundamental aspect of consciousness.” Your feelings are created by the beliefs of your brain, as informed by your interoceptive network. “A bad feeling doesn’t always mean something is wrong. It just means you’re taxing your body budget…. You might think that in everyday life, the things you see and hear influence what you feel, but it’s mostly the other way around: that what you feel alters your sight and hearing. Interoception in the moment is more influential to perception, and how you act, than the outside world is.” So your experience of the world is not an objective fact. “Your brain employs concepts to make the sensory signals meaningful, creating an explanation for where they came from, what they refer to in the world, and how to act on them. 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. Much of what you experience as the outside world begins inside your head…. Concepts are not static but remarkably malleable and context-dependent, because your goals can change to fit the situation…. So, what’s happening 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.” You cannot escape your past even if you try. Your past is embedded in how you see and interpret your future. It gives meaning to new sensory inputs.
Babies do not predict well. They must learn from sensory input before their brains can model the world. Eventually, “sensations from the outside world…. become concepts in the infant’s model of the world; what was outside is now inside. These sensory experiences, over time, create the opportunity for the infant brain to make coordinated predictions that span the senses.” Eventually, as an adult, “your cascade of predictions explains why an experience like happiness feels triggered rather than constructed. You’re simulating an instance of “Happiness” even before categorization is complete. Your brain is preparing to execute movements in your face and body before you feel any sense of agency for moving, and is predicting your sensory input before it arrives. So emotions seem to be “happening to” you, when in fact your brain is actively constructing the experience, held in check by the state of the world and your body…. An instance of a concept, as an entire brain state, is an anticipatory guess about how you should act in the present moment and what your sensations mean.” When a strange set of inputs occur, “your interoceptive network will launch hundreds of competing instances of different concepts, each a brain-wide cascade, to resolve this quandary. Your control network assists in efficiently constructing and selecting among the candidate instances so your brain can pick a winner. It helps neurons to participate in certain constructions rather than others, and keeps some concept instances alive while suppressing others. The result is akin to natural selection, in which the instances most suitable to the the current environment survive to shape your perception and action.” This all happens within your brain almost instantaneously and with no perceptible agency on your part. “Emotions are meaning. They explain your interoceptive changes and corresponding affective feelings, in relation to the situation.”
Emotion concepts, like sound and color, are a social reality. “A sound, therefore is not an event that is detected in the world. It is an experience constructed when the world interacts with a body that detects changes in air pressure, and a brain that can make those changes meaningful…. “Red” is not a color contained in an object. It is an experience involving reflected light, a human eye, and a human brain…. Changes in air pressure and wavelengths of light exist in the world, but to us, they are sounds and colors. We perceive them by going beyond the information given to us, making meaning from them using knowledge from past experience, that is, concepts. Every perception is constructed by a perceiver, usually with sensory inputs from the world as one ingredient…. Teach your concepts to others, and as long as they agree, you’ve created something real. How do we work this magic of creation? We categorize. We take things that exist in nature and impose new functions on them that go beyond their physical properties. Then we transmit these concepts to each other, wiring each other’s brains for the social world. This is the core of social reality…. If people agree that a particular constellation of facial actions and cardiovascular changes is anger in a given context, then it is so. You needn’t be explicitly aware of this agreement…. No other animals have collective intentionality combined with words…. Words also have power. They let us place ideas directly into another person’s head…. Words also encourage mental inference: figuring out the intentions, goals, and beliefs of others. Human infants learn critical information resides in the minds of other people…. and words are a vehicle for inferring this information.” But theory of mind goes beyond spoken words. To get inside the heads of others and anticipate and predict what they are thinking is a skill unique to humans. And it is how emotions become social. “Emotion concepts, like all concepts, make meaning…. They are real because people agree that they’re real.” They create a shared social reality, but you can only participate in that reality if you can correctly read and interpret the actions of others. If you are not perceiving the emotions of others correctly you become socially stunted, not able to interpret the shared constructions that make the social world real. “Emotions have no fingerprints, so there can be no accuracy. The best you can do is find consensus.” The emotional concept comes first. “You need an emotion concept in order to experience or perceive the associated emotion. It’s a requirement…. Otherwise, you will be experientially blind to that emotion…. You will be awash in prediction error much of the time. The process of acculturation therefore taxes your body budget. In fact, people who are less emotionally acculturated report more physical illness.”
The latter part of Barrett’s book “devolves” into still useful self help tips. Since you create your emotions, you can master them. “Emotional intelligence (EI) is about getting your brain to construct the most useful instance of the most useful emotion concept in a given situation.” On the other hand, “your body budget…. is regulated by predictive circuitry in your interoceptive network. If those predictions become chronically out of sync with your body’s actual needs, it’s hard to bring them back into balance.” Social rejection is toxic for your body budget. On the other hand, massage (and human touch in general), yoga (and any movement in general), meditation, reading novels (to get in other people’s minds and out of your own for a time), expanding your vocabulary (to recategorize concepts more favorably) and giving gifts to others all improve your body budget. “A key to EI is to gain new emotion concepts and hone your existing ones…. People who make highly granular experiences are emotion experts: they issue predictions and construct instances of emotion that are finely tailored to fit each specific situation…. Be a collector of experiences. Try on new perspectives…. These kinds of activities will provoke your brain to combine concepts to form new ones, changing your conceptual system proactively so you’ll predict and behave differently later…. When you teach emotion concepts to children, you are doing more than communicating. You are creating reality for these kids- social reality. You’re handing them tools to regulate their body budget, to make meaning of their sensations and act on them, to communicate how they feel, and to influence others more effectively.” Emotion is a social experience. “If you want someone to know what you are feeling, you need to transmit clear cues for the other person to predict effectively and for synchrony to occur…. You bear the responsibility to be a good sender.”
Barrett goes on to discuss the relationship between emotion and illness. “You could suffer prolonged stress or abuse, particularly in childhood, leaving you carrying around a model of the world built on toxic past experiences.” Many illnesses are also built upon prediction error in the brain. “When you are experiencing pain, like the moment just before an injection, your brain regions that process nociception change their activity. That is, you simulate pain and therefore feel it. This phenomenon is called the nocebo effect…. Both placebos and nocebos involve chemical changes in the brain that process nociception…. The pathways sending nociceptive predictions down to the body, and those bringing nociceptive input up to the brain, are closely related to interoception. (It’s even possible that nociception is a form of interoception.)… When people experience ongoing pain without any damage to their body tissue, it’s called chronic pain…. What would happen if your brain issued unnecessary predictions of pain and then ignored prediction error [from your body] to the contrary?” Likewise, “in depression, prediction is dialed way up and prediction error way down, so you’re locked into the past. In anxiety, the metaphorical dial is stuck on allowing too much prediction error from the world, and too many predictions are unsuccessful. With insufficient prediction, you don’t know what’s coming around the next corner, and life contains a lot of corners. That’s classic anxiety.” But you can change your own brain and in doing so change your emotional concepts. “Interconnections between your axons and dendrites increase and decrease as you age. You even grow new neurons in certain brain regions. This kind of anatomical change, called plasticity, also occurs with experience. Your experiences become encoded in your brain’s wiring and can eventually change the wiring, increasing the chances that you’ll have the same experience again, or use a previous experience to create a new one.” The human brain “can reconfigure its billions of neurons to construct a huge repertoire of experiences, perceptions, and behaviors…. Complexity, not rationality, makes it possible for you to be an architect of your experience…. The human brain has few preset mental concepts, such as perhaps pleasantness and unpleasantness (valence), agitation and calmness (arousal), loudness and softness, brightness and darkness, and other properties of consciousness. Instead, variation is the norm. The human brain is structured to learn many different concepts and to invent many social realities, depending on the contingencies it is exposed to…. The human brain is wired to construct a conceptual system…. What is not inevitable, however, is that you have particular concepts.” In the end, “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…. There is no single reality to grasp. Your brain can create more than one explanation for the sensory input around you- not an infinite number of realities, but definitely more than one.”
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