Your brain is the world’s most proficient accountant. Here’s how.

Courtesy photo

Right now, as you read this, your brain is performing a complex series of calculations and predictions designed to efficiently allocate resources such as salt, glucose, and water to the rest of your body. It’s interpreting waves of light, chemicals in the air, and the squiggles on this page, turning them into sights and smells and words. But all of this is in service of your brain’s most vital function: keeping you alive.

“Your brain is constantly running a budget for your body,” says Lisa Feldman Barrett, university distinguished professor of psychology at Northeastern.

Lisa Feldman Barrett, University Distinguished Professor. Photo by Matthew Modoono/Northeastern University

And with complex systems including “a cardiovascular system with a heart that pumps blood, a respiratory system that takes in oxygen and eliminates carbon dioxide, and an adaptable immune system that fights infection,” a body budget is far more complex than a single bank account, Barrett writes in her new book, Seven and a Half Lessons About the Brain.

“Your brain really functions more like the accounting department of a sizable company,” she says.

In her book, Barrett, a nationally renowned neuroscientist, offers up seven (and a half) short essays about the brain “that most people might not know and most neuroscientists may not even know,” she says. She debunks common myths—have you heard the one about our “lizard brain?”—and poses big questions about human nature.

The lessons are timeless, but several are particularly apt to our present moment, as Barrett has discussed in conversations with Jamie Ryerson, an editor at The New York Times, and Lulu Miller, a contributor to the popular podcasts Radiolab and NPR’s Invisibilia.

A human brain is in charge of budgeting resources including water, blood, salt, oxygen, glucose, cortisol, sex hormones, and dozens more, to keep a body running efficiently. When those resources are depleted—by lack of sleep, chronic stress, or a lackluster diet that deprives you of important nutrients—your body is more vulnerable to illness, Barrett says. 

For example, Barrett says, when a body budget is in the red, you’re more likely to develop a respiratory illness if you’re exposed to a virus.

“You can’t get sick without getting exposed to a virus, but not everyone who gets exposed to a virus gets sick, and if you’re chronically running a deficit, you’re more likely to get sick,” she says.

To compensate, your brain needs to stop spending resources when it’s running a deficit, just as you’d need to stop spending money if your bank account was in the red.

It’s not just physical health that’s jeopardized when our brains are overtaxed. Learning something new also takes up a large amount of resources, Barrett says, and it can be harder to do in times of poor health or high stress. That’s especially relevant, she says, at a  time when we’re struggling with pandemic-related stress—and are constantly bombarded with new information, which we use to make decisions about everything from what to watch on TV to which presidential candidates we support. 

So, when it comes time to scroll through Facebook or Twitter, it’s far easier for our weary brains to gravitate toward viewpoints and opinions that are similar to our own than to digest and consider the opposing idea, Barrett says.

“If things are predictable, they’re metabolically cheaper,” she says.

Writing the book, distilling these lessons into an approachable format, has given Barrett a new perspective, herself, she says.

“Like everybody else, I’m surfing this tsunami of stress,” she says, “but I try to cultivate empathy for people who think differently than me. I want to be the kind of person who leaves this world a little better than how I found it.”

For media inquiries, please contact Jessica Hair at or 617-373-5718.