Your willpower is like a muscle — pump it up.

If you have even a passing interest in self-improvement, productivity or psychology, you will no doubt have heard numerous times about the famous Stanford marshmallow/willpower study.

Basically, a scientist called Walter Mischel ran a borderline-sadistic experiment in the sixties to test the willpower of four-year-olds. He left them alone in a room with a tasty treat like a cookie, pretzel or marshmallow, and then told them they could eat the treat immediately, or, if they preferred, wait 15 minutes and get two treats. In short, the kids’ willpower was being tested: Could they resist the temptation for 15 painfully long minutes, if it meant doubling their treat?

The children, of course, were very tempted. Many did everything they could to hold out: some even covered their eyes or resorted to making silly noises to distract themselves from the sweet spongy siren that tempted them.

The results? About 30 percent of the children managed to abstain, which is not that fascinating on its own.

Things got more interesting though when Mischel followed up on the participants later on in life. It turned out that the children who had resisted temptation were more popular, did less drugs and went on to get significantly higher SAT-scores in high school than their less restrained peers. The remainder likely wound up in severe debt, doing deplorable things to get their next marshmallow fix.

This now legendary result has been interpreted to mean that the key to a better life is stronger willpower. The idea is echoed by New York Times reporter Charles Duhigg in his book “The Power of Habit,” where he suggests that of all the habits that shape our behavior, willpower is the most important one to learn because it has a positive spillover effect to all areas of life.

Academics agree, it seems. Consider this excerpt from an article written by some of the most prominent willpower (a.k.a “self-regulation” in the world of academia) researchers today:

One could go so far as to say it [self-regulation] is the single most important aspect because, given sufficient powers of self-regulation, any other personality trait can be overcome. In other words, if your self-regulation is powerful enough, then regardless of your inclinations, past experiences, or neuroses, you can always do the adaptive or right thing. Self-regulation can be the trump card of personality. (Baumeister, Oaten et al.)

It’s safe to say that willpower is a pretty big deal, and it impacts far more important things than the number of marshmallows you receive.

From marshmallows to radishes: why your willpower is like a muscle

Anyone talking about the importance of willpower is usually also quick to mention that in many ways, your willpower resembles a muscle: it can get tired from exertion.

To illustrate this, Duhigg mentions an experiment by researcher Mark Muraven. In this also borderline-sadistic experiment, Muraven presented hungry undergraduate students with two bowls of snacks: healthy radishes and heavenly, freshly-baked cookies.

The students were left alone in a room with the bowls for five minutes, half of them having been told to only eat cookies, the other half to only eat radishes. Afterwards, all students had to try to solve an impossible puzzle until they gave up.

And here it gets interesting: students who were not allowed to eat the cookies gave up much sooner than students who could eat the much more appealing cookies.

Conclusion? The radish-eating students had expended willpower on resisting the temptation of the cookies, and therefore had less willpower left to use on the puzzle task.

This phenomenon, known as “ego depletion”, explains why someone who has spent their day at work doing tedious, willpower-draining tasks is far more likely to succumb to temptation afterwards, for example by violating their diet or committing infidelity.

So what recommendations can be drawn from the rest of us?

Option A: Save your willpower for when the going gets tough

Many say that because willpower is like a muscle, you should try to deliberately keep it rested so you have enough to deal with any demanding situations.

In his book “The ONE thing”, Gary Keller encourages you to prioritize where you spend your willpower. So for example, if you have an important project at work, you should avoid expending your willpower on other less-important tasks. On the other hand, since Keller also stresses that your personal life is more important than your work life, you should conserve willpower for after work too, so you don’t argue or bicker with your family needlessly.

Duhigg also emphasizes these ideas in “The Power of Habit”, explaining that if, for example, you have decided to take on a new fitness regimen – like going jogging every night after work – you need to ensure you have enough willpower to adhere to it when you get home from work. Otherwise you may be unable to resist the temptation of the sofa and some potato chips.

On the face of it, this approach does seem reasonable: you conserve resources, like you do water in the desert.

However, there’s also an inherent problem here: we usually can’t control or decide when to use our willpower. Imagine your boss hands you a tedious task to do, and you tell her to take a hike because you need to conserve willpower to clean your garage later. It’s safe to say this might not go down so well.

Option B: Try to take willpower out of the equation

Did you occasionally have trouble mustering the willpower to brush your teeth and go to bed early as a child? Probably.

Did you do it anyway? Also probably yes, because your parents forced you to, no matter how much you kicked and screamed.

In a similar vein, some authors feel that the solution to insufficient willpower is to take willpower out of the equation entirely and set up rules and limitations that force you to do the right thing, whether you have the willpower or not. For example, if you are on a diet, you could get rid of all the unhealthy snacks around the house. That way, even if you do get tempted, you still won’t succumb as the only thing to munch in the house will be drywall.

In his bestseller Predictably Irrational, Dan Ariely demonstrates the power of this approach:

He conducted an experiment where his students’ tendency to procrastinate was measured. University students are, of course, famous procrastinators, often leaving all necessary coursework until the last possible minute. But this experiment showed that when allowed to set their own deadlines for their essays, some students acknowledged this weakness. They deliberately set themselves small, evenly-spaced deadlines throughout the course to force themselves to even out their own workload and not to procrastinate till the last-minute.

The results? Their grades were far better than those of students who only had one big deadline: the end of the course.

So in addition to the tactic of saving your willpower for when you need it, rules and limitations also sound like a very good idea. But both these approaches cast aside an interesting question: Does the muscle analogy extend further?

Option C: Put the “power” back in willpower!

Sure, exerting your muscles to exhaustion will make them temporarily weaker, but, in the long run, exertion also encourages your muscles to grow.

So if willpower truly is like a muscle, then by extension you should be able to strengthen it precisely by exerting it, not by conserving it or taking it out of the equation.

Obviously then, the best long-term solution for dealing with tomorrow’s challenges is to whip that wimpy thing you call willpower into a lean, mean, self-regulatin’ machine!

It’s no surprise then, that several scholars have also landed upon this idea, as illustrated by Duhigg in The Power of Habit:

Australian researchers Megan Oaten and Ken Cheng wanted to find out what would happen to self-professed couch potatoes if their willpower was challenged with a physical exercise program. After two months of participants dragging themselves to the gym, it was found that in addition to being in better physical shape, they also showed willpower-related improvements in other areas of their lives: They smoked less, drank less and ate less junk food. They also spent less time watching television and more time on productive tasks, such as homework.

Eager to expand on this study, Oaten and Cheng designed another one: This time the intended willpower workout was a four-month money management program, where participants had to keep detailed track of all their expenses. Once again, it was found that this exercise in self-discipline had positive spillover effects: not only did participants indulge less in cigarettes, alcohol and junk food, but they also became more productive at work and at school.

Other studies include some simpler willpower workouts.

For example, Mark Muraven and his colleagues found that simply focusing on improving your posture can help strengthen your overall willpower.

Also, Matthew Gailliot and his colleagues discovered that self-regulation can be improved by using your non-primary hand to perform daily tasks, like brushing your teeth, eating meals or using your computer mouse.

To varying degrees, these studies do suggest that it’s possible to exercise your willpower in one area of life and consequently strengthen it across the board. This is a willpower workout.

So this leaves us with a dilemma: What should you do, expend your willpower liberally in the hope it gets stronger, or conserve it so you don’t wind up blowing your diet or worse because you didn’t have the willpower to resist temptation?

Solution: Don’t tear your willpower muscle, but train it deliberately

Perhaps the muscle analogy provides guidance in this matter too: Sudden, unexpected strain on a muscle can result in a tear, damaging and weakening it, while planned and controlled exercise can strengthen it.

Similarly, perhaps it is only sudden, unexpected willpower-depleting events that are harmful, for example your boss surprising you with an urgent budget spreadsheet the size of Denmark on a Friday afternoon.

On the other hand, a controlled willpower workout, say willingly taking a few minutes each evening to track your expenses, can be beneficial.

It is a mere theory, but does suggest that you may well be right to conserve willpower at work, for example by saying “No” to unexpected tedious tasks, while simultaneously training your willpower in a systematic and controlled way.

So what are you waiting for? Time to put your willpower on a treadmill!