The Nuance

You Can’t Deplete Your Willpower

Your self-control can fluctuate, but you probably can’t use it up

Markham Heid
Published in
6 min readJan 14, 2021
Illustration: Kieran Blakey

January is the month for resolutions, which also makes it the month for self-control. Whether you’re giving up your favorite latte or cutting back on Instagram, avoiding these and other temptations can feel draining. It’s as though you only have so much willpower in your tank, and the more of it you use, the harder it becomes to follow through on your good intentions.

Experts have a name for this phenomenon: ego depletion. The term was introduced in the 1990s by a team of psychologists at Case Western Reserve University in Cleveland. They argued that your “volition” — that is, your ability to make choices or engage in effortful behaviors — is a limited resource. The more willpower you expend, the more vulnerable you are to failures of self-control.

Ego-depletion theory quickly became one of the hottest concepts in psychology. “The idea really took social psychology by storm. It’s not an exaggeration to say that for a while it was at the center of the field,” says Michael Inzlicht, PhD, a professor of psychology at the University of Toronto. Inzlicht himself was swept up in the ego-depletion furor and published work that supported its existence and significance.

“But then some cracks started to appear,” he says. Experts began asking what, exactly, was the resource in the brain that was being used up when a person exercised willpower? No one could say. More consequentially, researchers who tried to go back and replicate some of the most influential ego-depletion experiments found that their results didn’t hold up. Inzlicht discovered this when he reexamined some of his own work.

“Now I think the studies that ego-depletion theory was based on are bollocks, and I didn’t come to that belief lightly,” he says. “It’s partly my own work that I’m denigrating.”

But while the early ego-depletion concepts appear to be flawed, experts say that self-control can wax or wane for a number of predictable reasons. Understanding when and how this happens may help people avoid the kind of willpower failures that torpedo their aspirations.

It makes sense that you’d struggle to…



Markham Heid

I’m a long-time contributor at TIME and other media orgs. I write mostly about health. I grew up in Michigan, but these days I live in southwest Germany.