How Emotions Are Made: The Secret Life of the Brain

“None of these four meta-analyses found consistent and specific emotion fingerprints in the body. Instead, the body’s orchestra of internal organs can play many different symphonies during happiness, fear, and the rest.”

The author explains that a meta-analysis is the process of combining the results of various studies and analyzing the data they’ve produced. She clarifies that several meta-analyses failed to label certain “fingerprints” for emotions in the human body, and instead, variation was the rule. Again, this illustrates the importance of context in understanding emotions.

“This is one of the most surprising things I learned when I began to study neuroscience: 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.”

Barrett introduces the idea of degeneracy, which is the brain’s ability to create the same sensations through different combinations of neurons. Degeneracy shows that the human brain is too complex and varied to simply create the same reactions in the same ways as a response to external stimuli. Universally interpreting emotions is therefore a simplistic and inadequate approach.

“We will call it simulation. It means that your brain changed the firing of its own sensory neurons in the absence of incoming sensory input. Simulation can be visual, as with our picture, or involve any of your other senses. Ever have a song playing in your head that you can’t get rid of? That audio hallucination is also a simulation.”

The author explains that simulation enables the brain to channel visual and auditory neurons without external stimuli, allowing people to envision pictures or create tunes at will. Simulations also help the brain interpret for humans what’s happening around them.

“Now consider this: what if your brain uses this same process to make meaning of the sensations from inside your body—the commotion arising from your heartbeat, breathing, and other internal movements? From your brain’s perspective, your body is just another source of sensory input.”

Barrett raises the question of how the brain interprets bodily functions, hypothesizing that people’s use of concepts can easily help create emotions based on bodily sensations. For example, stomach pain may be interpreted as “hunger, nausea, or mistrust” depending on the context.

“This unfamiliar story creates a challenge because people expect stories with familiar structures […] Our challenge here is that the dynamics of the brain, and how emotions are made, do not follow a linear, cause-and-effect sort of story.”

Barrett acknowledges that the classical theory of emotion often feels more intuitive to people, and its ideas fit more neatly into familiar linear storytelling narratives. However, she argues that the brain is more complex than the classical view understands and, as such, her own argument won’t always seem neat or linear.

“You depend on emotion concepts each time you experience another person as emotional. Knowledge of the concept ‘Sadness’ is required to see a pout as sadness, knowledge of ‘Fear’ to see widened eyes as fearful, and so on.”

Barrett synthesizes a major aspect of her argument: emotion concepts, which she argues are necessary for humans to develop so that they can perceive emotions in others. This sharply contrasts with the classical view, which posits that all humans are born with an innate understanding of emotions in themselves and others.

“If humans actually had an inborn ability to recognize emotional expressions, then removing the emotion words from the method did not matter […] but it did, every single time. There is very little doubt that emotion words have a powerful influence in experiments, instantly casting into doubt the conclusions of every study ever performed that uses the basic emotion method.”

The author points out a prevailing flaw in basic emotion method studies: that they provide study subjects with multiple-choice emotion word answers such as “happiness” or “fear.” She notes that when these words are removed and study subjects come up with their own terms, their answers vary much more widely than the multiple-choice suggestions would allow. This further substantiates the inadequacy of standardizing emotion interpretation.

“Simple pleasant and unpleasant feelings come from an ongoing process inside you called interoception. Interoception is the brain’s representation of all sensations from your internal organs and tissues, the hormones in your blood, and your immune system."

Barrett explains that interoception is the brain’s way of creating pleasant or unpleasant feelings based on all perceived sensations. This process is present in all animals and is key to survival; it’s also essential to being able to experience emotions. Emotions are based on multiple stimuli throughout the body that continuously influence and interact with each other.

“And so, trapped within the skull, with only past experiences as a guide, your brain makes predictions […] I’m focusing on predictions at a microscopic scale as millions of neurons talk to one another. These neural conversations try to anticipate every fragment of sight, sound, smell, taste, and touch that you will experience, and every action that you will take. These predictions are your brain’s best guesses of what’s going on in the world around you, and how to deal with it to keep you alive and well.”

This passage paints a picture of our brains as incessant predictors, generating predictions instantaneously based on every kind of sensory information. These predictions are crucial to helping us understand the world and decide how to behave—and are also crucial to generating emotions.

“If your brain were merely reactive, it would be too inefficient to keep you alive […] A reactive brain would also be too expensive, metabolically speaking, because it would require more interconnections than it could maintain. Evolution literally wired your brain for efficient prediction.”

The author argues that merely generating reactions to external stimuli wouldn’t make metabolic sense, since the brain would expend more energy trying to process the massive amount of constant sensory information and require more interconnections. Instead, the brain is adapted for efficiency by constantly making predictions about the world and testing them against sensory input—and against past experiences.

“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, of anything else—and it imposes similarities between them, in the moment, according to your goal in a given situation.”

According to Barrett, the brain’s flexible ability to create categories of diverse items or instances helps create nuanced emotion concepts that include a variety of situations and expressions. These concepts constantly adapt and create new instances based on the body’s present condition and factors relevant to it, like location and social environment. Older instances may fade but aren’t replaced.

“If I am correct, then, as children continue to develop their concept of ‘Anger,’ they learn that not all instances of anger are constructed for the same goal in every situation. ‘Anger’ can also be for protecting oneself against an offense, dealing with someone who acted unfairly, desiring aggression toward another person, wanting to win a competition or to enhance performance in some way, or wishing to appear powerful.”

Barrett notes the importance of language in teaching children emotion concepts. By hearing the word “anger” in a variety of situations, children come to understand that anger can manifest itself differently and be expressed for different reasons. In addition, different cultures sometimes assign anger and other emotions differently. In childhood and throughout life, human experience instructs on the complexity of emotion concepts.

“Emotion words are not about emotional facts in the world that are stored like static files in your brain. They reflect the varied emotional meanings you construct from mere signals in the world using your emotion knowledge. You acquired that knowledge, in part, from the collective knowledge contained in the brains of those who cared for you, talked to you, and helped you create your social world.”

The author emphasizes the immense impact of cultural influence and socialization on our ability to form and perceive emotions. She urges an understanding that the brain helps construct meaning from the world rather than merely reacting to it. Exposing the brain to a wide range of experiences throughout life thus enhances emotional intelligence.

“Your brain captured the entire sensory context in the moment, as a pattern of sights, smells, sounds, tastes, and touches, and interoceptive sensations. This is how concepts begin to form. You learn in a multisensory way. Your inner-body changes and their interoceptive consequences are part of every concept you learn whether you’re aware of it or not.”

In this passage, the author explains that while concepts can feel purely mental, they’re learned in a contextual, “multisensory” fashion in which all of the sensing capabilities contribute to the understanding of a concept. Much of this process occurs subconsciously. A feeling is based on the brain’s efficiently processing a vast amount of information.

“When your brain constructs an ‘instance of a concept,’ such as the instance of ‘Happiness,’ that is the equivalent to saying your brain ‘issues a prediction’ of happiness […] Think of prediction as ‘applying’ a concept, modifying the activity in your primary sensory and motor regions, and correcting or refining as needed.”

Barrett clarifies that while she has discussed predictions and concepts separately, they’re both part of the same phenomenon happening in the brain. These concepts/predictions are what allow us to experience emotions. The brain constantly references past instances, makes predictions, and refines concepts.

“Your control network helps select between emotion and non-emotion concepts (is this anxiety or indigestion?), between different emotion concepts (is this excitement or fear?) between different goals for an emotion concept (in fear, should I escape or attack?), and between different instances (when running to escape should I scream or not?).”

The brain’s control network interacts with the interoceptive network to help the brain identify its emotion concepts and apply them appropriately depending on the situation. These networks communicate via major hubs that are essential to consciousness and healthy brain function.

“Emotions are meaning. They explain your interoceptive changes and corresponding affective feelings, in relation to the situation. They are a prescription for action. The brain systems that implement concepts, such as the interoceptive network and the control network, are the biology of meaning-making.”

The author emphasizes emotions’ role in the brain’s attempt to interpret the outer world as well as bodily functions. By calling emotions a “prescription for action,” Barrett highlights how feelings inform behavior in significant ways.

“Emotions are real, but real in the same manner as the sound of a tree falling, the experience of red, and the distinctions between flowers and weeds. They are all constructed in the brain of a perceiver.”

Barrett argues that emotions are perceiver dependent since they require a human brain to recognize and process them and don’t exist in isolation. To identify and process emotions requires social reality, which dictates how humans express and interpret emotion.

“Emotions are social reality. We construct instances of emotion in exactly the same manner as colors, falling trees, and money: using a conceptual system that is realized within our brains’ wiring […] First, you need a group of people to agree that a concept exists, such as ‘Flower,’ or ‘Cash,’ or ‘Happiness.’ This knowledge is called collective intentionality.”

Barrett argues that experiences of emotion can’t be separated from social and cultural contexts, since emotion concepts are based on input from social examples. Agreeing on emotion concepts establishes collective intentionality and thereby creates a shared social reality.

“I am not saying emotions are illusions. They are real, but socially real in the manner of flowers and weeds. I’m not saying everything is relative…I am also not saying that emotions are “just in your head.” That phrase trivializes the power of social reality."

Barrett clarifies her stance on the social reality of emotions, arguing that social reality is a powerful and consequential thing and that she isn’t trivializing emotions or interpreting all of human life as ‘relative.’

“In this view, culture is not some gauzy, amorphous vapor that surrounds your brain. It helped to wire your brain, and you behave in certain ways that wire the brains of the next generation […] Your genes gave you a brain that can wire itself to its physical and social environment, and other members of your culture construct that environment with you. It takes more than one brain to create a mind.”

Barrett advances her theme of culture’s enormous influence on brain development and function, explaining that cultural experiences help wire the brain in certain ways, influencing how humans form our thoughts and emotions. This means that the human brain is more flexible and neuroplastic than the classical view of emotion allows for.

“When we peer into the workings of a functional brain, we don’t see mental modules. We see core systems that interact continuously in complex ways to produce many sorts of minds, depending on culture. The human brain is itself a cultural artifact because it is wired by experience.”

Building on her argument that culture helps wire the brain and teach concepts, Barrett calls the brain a “cultural artifact” since it’s shaped by human experiences, including those of ancestors.

“The most basic thing you can do to master your emotions, in fact, is to keep your body budget in good shape. Remember, your interoceptive network labors day and night, issuing predictions to maintain a healthy budget, and this process is the origin of your affective feelings (pleasantness, unpleasantness, arousal, and calmness)."

The author reinforces the relationship between emotions and body budgets in her recommendations. She notes that without a functional and healthy interoceptive network that makes accurate predictions about energy needs, humans simply couldn’t feel pleasant feelings regularly and enjoy life.