You’ve heard that grit matters. But is grit alone the secret to success?

In Situated: Find the People and Places That Bring Out Your Best, Angela Duckworth explores how your situation—the objects around you, your peers, your mentors, your physical environment—shapes who you become. In this excerpt, she explains her central framework: the three boxes model of human behavior (situation, thoughts, response) and how understanding this can help you reverse-engineer your own behavior and make intentional changes to your circumstances.

This partial transcript has been edited and condensed for clarity.

John Dickerson:Now that you’ve been on a book tour for a while, what is your simplest way of helping people understand? 

Angela Duckworth: The power of the will?

… the thesis of this book? Yeah.

I mean, willpower is a great word by the way, right? The “power of the will.” The science of willpower is that there is part of the brain toward the front, toward the lateral prefrontal cortex, that is in charge of ordering around the rest of your brain. And you can force yourself to do things that you don’t want to do in the moment. You can say, “I don’t really want to look at this Google Doc, and pound through another revision of this memo that I’m writing,” but you can force yourself to do it. You can force yourself to stop eating— “I’m just going to put that french fry down.” That’s your dorsolateral prefrontal cortex at work. We all know what it feels like, even children recognize the feeling of effort, the effort of suppressing impulses.

By the way, I need to tell you, John, that’s not grit.Willpower is not grit. People do not become Olympic gold medalists because they suppress impulses all day long. They have a different motivation.

But let’s talk about willpower because so many of us understand that that has been part of our success, that we have done that before. We have forced ourselves not to eat things, to eat things, to drink things, not to drink things, to wake up, to get along… But here’s what the science of willpower has said over the last 20 years: When scientists began to study very successful people in terms of people who say, “This is my goal for the week,” you come back to them, and you’re like, “Did you achieve the goal?” Now, we can understand the people who did achieve their goal, versus those who did not. What was revealed was quite surprising, which is that it’s actually not willpower that’s doing most of the work.

People who achieve their goals avoid the distractions and temptations that get in the way. They avoid the friction. They actually create opportunities where it is the natural and automatic thing to eat the way they want, drink the way they want, exercise the way they want, work the way they want, even relate to other people the way they want. And so, that actually is what’s been occupying me in large part for the last 10+ years in my research. And I think that was one reason I felt like I needed to complete the story, not because grit and willpower are the same thing, but of course we have goals that come into conflict with our immediate desires—gritty people too—but it was clear to me from the research that I was doing, and the other scientists who work on behavior change, that this American myth of willpower is so dangerously incomplete.

And part of that myth is the conflation between willpower and grit. So, I’ve demonstrated something for listeners-

Well, we got to nuance, John, which I think is only possible in a real conversation.