Is Your Willpower Limited Or Unlimited?

✅ Today's Tuesday • 📖 14 mins read

Willpower is the ability to resist short-term temptations in order to meet long-term goals.

A 5-year-old hears from her parents that she can get anything in life if she only has the willpower. Now imagine how frustrating it is for that child to carry the weight of that belief as she moves through life’s obstacles.

Adults get the same advice: all we need to beat the tough times is a strong will. We can use willpower to stop a social media scrolling habit, resist a tantalizing tiramisu, or start a new exercise routine.

We follow the handed-down wisdom, but we still keep failing. What are we doing wrong? Should we stop relying on willpower when things get tough?

Is willpower an overrated concept? Is our willpower limited or unlimited?

Is Willpower Limited or Unlimited?

Many people consistently report that a lack of willpower is the top reason they fall short of their goals. But the science-based fact is, willpower isn’t supplied in unlimited amounts.

Willpower is the ability to resist short-term temptations to meet long-term goals. But this ability to resist often grows weak after repeated acts of self-control. If we keep drawing from its limited reservoir, it will eventually run dry.

Why does it happen? Because each decision to suppress a temptation or push through discomfort drains our resources like attention and executive control. And that makes subsequent resistance harder and more error-prone.

“Chasing your goals and meeting obligations wears down your willpower. Over time, repeated self-control makes resisting temptation harder.” – Dr. Sandip Roy

Kathleen Martin Ginis, associate professor at McMaster University, found that using willpower in one task exhausts willpower for another, different task (Rough Day At Work? You Won’t Feel Like Exercising).

She said, “Cognitive tasks, as well as emotional tasks such as regulating your emotions, can deplete your self-regulatory capacity to exercise.”

So, discharging the willpower battery for one purpose means there’ll be less left over for others.

Still, Ginis doesn’t see that as an excuse to let people loaf on the sofa.

“There are strategies to help people rejuvenate after their self-regulation is depleted,” she says. “Listening to music can help, and we also found that if you make specific plans to exercise — in other words, making a commitment to go for a walk at 7 p.m. every evening — then that had a high rate of success.”

• This weakening of willpower is one reason people following willpower-based self-help programs often end up disappointed. Because the strength of their will often doesn’t help them reach their multiple goals. Willpower alone cannot help us carry through our hard decisions, like our weight-loss or quit-smoking goals, or bigger, ultimate goals of life.
• Fueled by willpower, this constant pressure to keep moving makes us run out of energy. The resulting fatigue is not only of your body, but it is also of your brain. And when your brain gets overwhelmed, your willpower gets depleted.

“People whose willpower was depleted by self-control tasks showed decreased activity in the anterior cingulate cortex, a brain region involved with cognition. When your willpower has been tested, your brain may actually function differently,” the American Psychological Association reports.

The anterior cingulate cortex (ACC) isn’t “running low on fuel” in any simple sense. Research suggests it is constantly weighing whether the effort a task demands is still worth the expected reward (Kurzban et al., 2013). When the math no longer works out in the task’s favor, the ACC starts steering attention elsewhere. That shift feels like depletion from the inside.

Is Willpower Like A Muscle You Can Train or Drain?

Is it true that willpower is like a muscle that weakens with exertion but strengthens with practice? More importantly, can we train it to be stronger for when we need it?

The muscle theory of willpower was first suggested by the famous psychologist Roy F. Baumeister, who proposed the “strength model of self-control.” He later co-wrote a book on this with John Tierney called Willpower: Rediscovering the Greatest Human Strength.

Speaking to NPR back in 2011, John Tierney said of willpower, “In the last 15 years, we’ve discovered that it really is a form of energy in the brain. It’s like a muscle that can be strengthened with use, but it also gets fatigued with use.”

Similar to a muscle, willpower can be strengthened over time. It needs to be challenged to build itself.

For example, by forcing yourself to do a late evening workout when you would rather be watching TV, you may find it hard to resist the temptation of an icy beer at night.

Surprisingly, way back in the 1960s, psychologist Walter Mischel ran one of the most famous willpower experiments in history: The Marshmallow Test.

A researcher put a marshmallow in front of each child and said they would leave the room and come back after a while. They offered the deal: the child could eat the marshmallow right away, but if they waited until the researcher came back, they would get two marshmallows.

Some kids ate the marshmallow as soon as the researcher left. Some wiggled and bounced, trying to stop themselves, but ate the marshmallow a few minutes later. A few waited for the researcher to return; they could delay gratification.

The researchers followed all these children for more than 40 years, noting how they progressed through life. Surprisingly, those who had waited out the entire time had better SAT scores, lower substance abuse, better responses to stress, better social skills, better health, and higher income.

Mischel concluded that a big part of our success as adults depends on how strong our willpower was as children. He also proposed that all children can be taught to have stronger willpower.

“Being able to call upon your willpower will serve you well in school and beyond. In fact, self-discipline may be even more important than IQ when it comes to predicting academic success.”

Mischel later wrote a successful book on it: The Marshmallow Test: Why Self-Control Is the Engine of Success. In the book, he explains why the ability to delay gratification is critical for a successful life.

One important caveat: a large replication study found that the predictive power of the marshmallow test largely disappears once you control for socioeconomic background and family environment (Watts, Duncan, & Quan, 2018).

A University of Rochester study adds another layer: children who had reliable experiences just before the test, that is, a researcher who made a small promise and kept it, waited nearly four times longer than children who had been let down moments earlier (Kidd, Palmeri & Aslin, 2013).

The child’s behavior wasn’t a fixed trait. They responded almost immediately to environmental cues about whether waiting was worth it.

Willpower is often trust: trust that the reward will actually arrive.

In his book, Mischel explains how self-control can apply to challenges in everyday life. He also suggests that we can learn to train our willpower to become stronger.

Paying the mortgage, buying groceries, or saving money require brain power devoted to making financial decisions. These financial decisions, big or small, require willpower.

[Find out what secrets Kelly McGonigal reveals about willpower in these 20 picture quotes.]

Cookies And Radish: The Willpower Experiment

In 1996, scientists did an interesting experiment. They brought in groups of college students who volunteered to participate.

They put the students in a room with the smell of warm chocolate chip cookies, and there were actual cookies too. The authors, led by Baumeister, published their results in the Journal of Personality and Social Psychology two years later.

Then they saw two bowls. One filled with fresh chocolate cookies, and the other with red and white radishes. The researchers then instructed them to eat from only one bowl without touching the other. So, they could only eat either the cookies or the radishes, as assigned.

In the second part of the experiment, after 15 minutes, the participants received a group of puzzles to solve, not realizing that these were actually impossible to solve.

The Baumeister team reasoned that the radish-eaters would have used and exhausted their limited self-control reserves while resisting the cookies. And this is reflected in the results, beautifully.

Those who had cookies kept trying the puzzles for an average of 19 minutes each before giving up, while those who ate radish gave up after only 8 minutes. The researchers concluded that the radish-eaters had already used up their willpower while resisting the cookies, so they gave up earlier.

Thus was born the theory of Ego Depletion.

Rise of Ego Depletion: Does Willpower Come In A Limited Supply?

Our self-control or willpower is a limited stock warehouse. We can deplete it by overuse. That, in essence, is the influential theory of ego depletion.

Suppose you want to bring in a slew of improvements in your life this summer. The theory advises you to choose and focus on only a few changes at a time. If too many, they’ll compromise one another by each drawing off from your willpower for its own use.

If you make a new plan to exercise for 30 minutes + meditate for 20 minutes + play tennis for 45 minutes + write 1,000 words + read 15 pages + and learn French 1 lesson every day, you will likely get nowhere with most of them after a few days.

Focus on one or two, and you would fare fine.

If someone had a bad day at work, then they might have a hard time resisting their third drink and fifth cigarette on their way back home. Why? They had depleted their willpower at the office, and now they didn’t have any to resist those unhealthy choices.

That’s ego depletion at work. When your willpower runs out during the day, it will be harder for you to feel guilty about indulging in a self-harming habit towards the end of the day.

You are simply too fatigued to care.

Habitual dieters are another case, who are trying to resist their food cravings (“food noise“) all the time. Chronic fatigue is often the result. Ego depletion is at play again.

Fall of Ego Depletion: Is Your Willpower Unlimited?

Here’s the problem with the ego-depletion theory: Your willpower may not have muscle-like properties at all. So, overusing your self-control may not exhaust it after all.

The brain is an organ, not a muscle, and thus does not consume extra energy the way a muscle would. Your brain uses the same number of calories per waking minute whether you’re working on calculus equations or watching cat videos.

— Nir Eyal, author of Hooked – How to Build Habit-Forming Products

But why do we say that?

Actually, there is no direct scale to measure ego depletion. Every study is a measure of persistence at the second task after a demanding first task. Scientists call it a sequential-task paradigm.

And ever since that original experiment, scientists around the world have sporadically failed to get the same results when they re-enacted the experiment in their own labs. Scientists call it replication failure.

• In 2013, Carter and McCullough found that the ego depletion effect was much smaller than reported. They said it may actually even be zero. They published their meta-analysis report with this contentious title: Is ego depletion too incredible?
• In the same year, 2013, Carol Dweck, author of Mindset: The New Psychology Of Success, and her team published a study in Proceedings of the National Academy of Sciences. They observed that only those test subjects who believed willpower was a limited resource showed ego depletion. Those who did not see willpower as a limited resource did not show ego depletion.
• A study published in PLOS (No Evidence of the Ego-Depletion Effect) in February 2016 found ego depletion not worthy of scientific curiosity. It wrote: “These findings add to a growing body of evidence suggesting ego-depletion is not a reliable phenomenon.”
• Perhaps the biggest blow to ego depletion came in July 2016. Twenty-three labs studying over 2,100 participants found that draining self-control at one task had almost zero effect on people’s capacity for self-control in a later task. All the experimenters failed to find any evidence for the theory.

Authors of the 2016 study published the upsetting results with these words in conclusion: “Results from the current multi-lab registered replication of the ego-depletion effect provide evidence that, if there is any effect, it is close to zero.”

Close to zero. This was a sharp jab and added fire to the raging credibility crisis in psychology.

Apparently unhappy, Baumeister replied, blaming the experimenters squarely. He said they failed to get the same results as his original cookie-radish experiment because the project coordinators of the Registered Replication Report allowed none of his suggestions, and they rejected his original protocol.

Baumeister’s published statement carried the title Misguided Effort With Elusive Implications. Now that is akin to ‘thermonuclear’ in academia.

What has emerged from the wreckage of ego depletion is a more nuanced explanation. Researchers Michael Inzlicht and Brandon Schmeichel proposed what they call the “process model” of self-control (Inzlicht & Schmeichel, 2012).

Their argument: what we experience as depletion isn’t a tank running empty. It’s a motivational shift. After sustained effort on a demanding task, the brain starts to prioritize activities that feel rewarding over activities that feel like work. You’re not out of willpower. Your brain has quietly renegotiated its priorities.

This reframe is significant. It means the experience of depletion is real, but its cause is motivational, not metabolic.

With help from family, friends or a psychologist, you can develop willpower and stay on track with your goals.

Sugar Theory of Self-Control: Can Sugar Refuel Your Willpower?

Have you heard about the Sugar Theory of Self-control?

A 2007 review (The Physiology of Willpower: Linking Blood Glucose to Self-Control) found that blood glucose is an important energy source for willpower. The review suggested that doing things that need self-control sap large amounts of glucose from the blood.

And when the blood glucose is low, the brain doesn’t get enough of it. Which, in turn, makes the brain fail on further tasks of willpower.

The APA mentions this experiment: “One study, for example, found that drinking sugar-sweetened lemonade restored willpower strength in depleted individuals while drinking sugar-free lemonade did not.”

In simple words, according to those researchers, the brain powers itself on blood sugar. And when you’re using your willpower too much, burnout follows. When your brain is working hard to keep up control, it starts consuming glucose at a faster pace than it can replenish itself.

By the way, here’s the turn-off. The idea that sugary drinks can replenish your willpower has been proven to be wrong.

In a paper titled The Bitter Truth About Sugar and Willpower, Miguel Vadillo and his team reviewed 19 published papers and found the relationship between glucose levels and self-control unreliable.

There is a more interesting finding underneath that debunking. Several studies found that simply rinsing the mouth with a glucose solution (without swallowing) was enough to briefly improve persistence on demanding tasks (Hagger & Chatzisarantis, 2013). The calories never entered the bloodstream. The effect was entirely a signal to the brain.

That tells you something important: what we call a “willpower boost” from sugar is a psychological response, not a metabolic refuel.

So, don’t gulp down a glass of sweetened water to tank up your self-control again; it’s useless.

Final Words: What The Science Actually Says Now

In a November 2016 article, Nir Eyal, the Israeli-American author, asked: Have we been thinking about willpower the wrong way for 30 years?

The short answer, based on where the research now sits, is yes.

The “limited resource” model that dominated pop psychology for two decades has not held up. The large-scale replications failed. The glucose theory failed.

What has survived is more useful: willpower is less about raw capacity and more about how you manage motivation and context.

Dweck’s finding is probably the most actionable result to come out of this entire debate. If you believe willpower is unlimited, you are far less likely to experience the performance drop that ego depletion predicts. Your beliefs about willpower shape how willpower actually works for you [Dweck et al., 2013].

Beyond mindset, the research points to one consistent practical finding: people who appear to have strong self-control tend to use it less, not more. They arrange their environments to reduce the number of decisions that require resisting temptation. They rely on habits, routines, and if-then plans — “If it’s 7 p.m., I go for a walk” — to take willpower out of the equation entirely.

That’s a more honest picture of what self-control looks like in practice. Less white-knuckling, more design.

√ Also Read: Do you know your kid’s willpower could determine their future?

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