A Simple Equation to Start or Break Any Habit

Every behavior comes down to three variables

BJ Fogg


Photo: Deby Suchaeri/Getty Images

YYou can change your life by changing your behaviors. You know that. But as I’ve found in my research as the founder and director of Stanford’s Behavior Design Lab — and as most of us know firsthand — there is a painful gap between what people want and what they actually do.

It took me 10 years of researching human behavior to realize that, when it comes to changing habits, the problem usually isn’t our lack of motivation or discipline. It’s our approach to change. It’s a design flaw, not a personal one.

Every behavior comes down to three variables: motivation, ability, and prompt. Motivation is your desire to do the behavior. Ability is your capacity to do the behavior. And prompt is your cue to do the behavior.

In my work, I group these three things together under the acronym MAP. A behavior (B) happens when the three elements of MAP come together at the same moment: B=MAP.

There are some nuances to the equation. First, motivation and ability have a compensatory relationship: The more motivated you are to do a behavior, the more likely you are to do the behavior. The harder a behavior is to do — that is, the lower your ability — the less likely you are to do it. In this sense, motivation and…