How the Brain Makes Emotions

This post continues on from the summary of chapter 5 (Concepts, Goals, and Words) in Barrett’s book "How Emotions Are Made: The Secret Life of the Brain" to chapter 6 (How the Brain Makes Emotions). The next installment of this series continues on to chapter 7, "Emotions as Social Reality":

When your brain “constructs an instance of a concept,” such as an instance of “Happiness,” that is equivalent to saying your brain “issues a prediction” of happiness...I separated the ideas of predictions and concepts earlier to simplify some explanations. I could have used the word “prediction” throughout the book and never mentioned the word “concept,” or vice versa, but information transmission is easier to understand in terms of predictions flying across the brain, whereas knowledge is more readily understood in terms of concepts. Now that we’re discussing how concepts work in the brain, we must acknowledge that concepts are predictions.

Early in life, you build up concepts from detailed sensory input (as prediction error) from your body and the world. Your brain efficiently compresses the sensory input it receives, just like YouTube compresses video, extracting similarities out of differences, eventually creating an efficient, multisensory summary. Once your brain has learned a concept in this manner, it can run this process in reverse, expanding the similarities into differences to construct an instance of the concept, much as your computer or phone expands the incoming YouTube video for display. This is a prediction. Think of prediction as “applying” a concept, modifying the activity in your primary sensory and motor regions, and correcting or refining as needed.

Each time you categorize with concepts, your brain creates many competing predictions while being bombarded by sensory input. Which predictions should be the winners? Which sensory input is important, and which is just noise? Your brain has a network to help resolve these uncertainties, known as your control network. This is the same network that transforms an infant’s “lantern” of attention into the adult “spotlight” you have now.

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 current environment survive to shape your perception and action.

The name “control network” is unfortunate because it implies a central position of authority, as if the network were making decisions and conducting the process. This is not the case. Your control network is more of an optimizer. It constantly tinkers with the information flow among neurons, ramping up the firing rate of some neurons and slowing down others, which moves sensory input in and out of your attentional spotlight, making some predictions fit while others become irrelevant. It’s like a car-racing team that constantly optimizes the engine and body to make a car slightly faster and safer. This tinkering ultimately helps your brain simultaneously to regulate your body budget, produce a stable perception, and launch an action.

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?). When you’re watching a movie, your control network might favor your visual and auditory systems, transporting you into the story. At other times it might background the traditional five senses in favor of more intense affect, resulting in an experience of emotion. Much of this tinkering happens outside your awareness.

Some scientists refer to the control network as an “emotion regulation” network. They assume that emotion regulation is a cognitive process that exists separately from emotion itself, say, when you’re pissed off at your boss but refrain from punching him. From the brain’s perspective, however, regulation is just categorization. When you have an experience that feels like your so-called rational side is tempering your emotional side—a mythical arrangement that you’ve learned is not respected by brain wiring—you are constructing an instance of the concept “Emotion Regulation.”

Your control network and interoceptive network are critical for constructing emotion. Moreover, these two core networks together contain most of the major hubs for communication throughout the entire brain. Think about the world’s largest airports that serve multiple airlines. A traveler in JFK International Airport in New York can switch between American Airlines and British Airways because the two airlines overlap there. Likewise, information can pass efficiently between different networks in your brain via the major hubs in the interoceptive and control networks.

These major hubs help to synchronize so much of your brain’s information flow that they might even be a prerequisite for consciousness. If any of these hubs become damaged, your brain is in big trouble: depression, panic disorder, schizophrenia, autism, dyslexia, chronic pain, dementia, Parkinson’s disease, and attention deficit hyperactivity disorder are all associated with hub damage.

The major hubs in your interoceptive and control networks make possible what I describe in chapter 4, that your everyday decisions are driven by your body-budgeting regions—your inner, loudmouthed, mostly deaf scientist who views the world through affect-colored glasses. You see, your brain’s body-budgeting regions are major hubs. Through their massive connections, they broadcast predictions that alter what you see, hear, and otherwise perceive and do. That’s why, at the level of brain circuitry, no decision can be free of affect.

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.

So, now you know how emotions are made in the brain. We predict and categorize. We regulate our body budgets, as any animal does, but wrap this regulation in purely mental concepts like “Happiness” and “Fear,” that we construct in the moment. We share these purely mental concepts with other adults, and we teach them to our children. We make a new kind of reality and live in it every day, mostly unaware that we are doing so.