By Clay Skipper

At the very beginning of her new book Seven and a Half Lessons About the Brain psychology professor Lisa Feldman Barrett writes that each chapter will present “a few compelling scientific nuggets about your brain and considers what they might reveal about human nature.” Though it’s an accurate description of what follows, it dramatically undersells the degree to which each lesson will enlighten and unsettle you. It’s like lifting up the hood of a car to see an engine, except that the car is you and you find an engine that doesn’t work at all like you thought it did. 

For instance, consider the fourth lesson, You Brain Predicts (Almost) Everything You Do. “Neuroscientists like to say that your day-to-day experience is a carefully controlled hallucination, constrained by the world and your body but ultimately constructed by your brain,” writes Dr. Barrett, who is a University Distinguished Professor at Northeastern and who has research appointments at Harvard Medical School and Massachusetts General Hospital. “It’s an everyday kind of hallucination that creates all of your experiences and guides all your actions. It’s the normal way that your brain gives meaning to the sensory inputs from your body and from the world (called “sense data”), and you’re almost always unaware that it’s happening.”

People tend to feel like we’re reacting to what’s actually happening in the world. But what’s really happening is that your brain is drawing on your deep backlog of experience and memory, constructing what it believes to be your reality, cross-referencing it with incoming sense data from your heart, lungs, metabolism, immune system, as well as the surrounding world, and adjusting as needed. In other words, in a process that even Dr. Barrett admits “defies common sense,” you’re almost always acting on the predictions that your brain is making about what’s going to happen next, not reacting to experience as it unfolds. (Michael Pollan details the same neurological process in his book How to Change Your Mind.)

“Predictions transform flashes of light into the objects you see. They turn changes in air pressure into recognizable sounds, and traces of chemicals into smells and tastes. Predictions let you read the squiggles on this page and understand them as letters and words and ideas,” Barrett writes. “They’re also the reason why it feels unsatisfying when a sentence is missing its final.”

In her first book, How Emotions Are Made, Dr. Barrett cites research that suggests something similar happens with emotion. We experience things like anger or anxiety as feelings caused by outside events. But really, as Dr. Barrett says, “Emotions don’t happen to you—they are made by your brain as you need them.” That may sound like splitting hairs, but the consequences are quite profound: The more you know about emotions, the more precisely your brain can construct them, so you will feel and act in ways that are very specific to the situation. We talk a lot about “handling” emotions after they emerge (this is called emotion regulation), but understanding emotions as something you construct allows you to influence how they arise in the first place.

Of course, this upends notions of how we experience reality and leads to some interesting questions. Why does this happen? If we construct the reality around us, including our emotions, does that mean we can change how we feel? What should we do with the anxiety and stress brought on by coronavirus? If our actions are dependent on past experience, do we control what we do? How do we think about responsibility—say, in the renewed conversation around police violence—in a world like that? How can we use these seven and a half lessons to better exist in the world?