How Willpower Works

Like their ancient toga-wearing counterparts, modern philosophers continue to disagree on the nature of freewill. Do we really have any control over the choices we make and the things we desire, and if so, to what degree?

Theories of freewill vary, but the ancient words of Plato still line up with our modern perceptions of temptation and willpower. The revered Greek philosopher argued that the human experience is one of constant struggle between the intellect and the body, between rationality and desire. Along these lines, true freedom is only achievable when willpower unchains us from bodily, emotional, instinctual slavery.

You can find similar sentiments throughout world religions, most of which offer a particular and often difficult path to rise above our darker natures.

And science? Well, science mostly agrees with all of this. Willpower is all about overcoming your natural impulses to eat cupcakes, skip your morning workout, flirt with the waiter, hit the snooze alarm and check your e-mail during a funeral.

Your willpower, however, is limited. If life were a video game, you'd see a glowing "willpower" or "ego" meter at the top of the screen next to your "life" meter. Successfully resist one temptation, and the meter depletes a little. The next temptation depletes the "willpower" meter even more, until there's nothing left at all.

Our modern scientific understanding of willpower in large part stems from a 1996 research experiment involving chocolate and radishes. Psychologist Roy Baumeister led a study in which 67 test subjects were presented with tempting chocolate chip cookies and other chocolate-flavored treats before a persistence-testing puzzle. Here's the catch: The researchers asked some of the participants to abstain from sweets and snack on radishes instead.

Baumeister's results told a fascinating story. The test subjects who resisted the sweet stuff in favor of radishes performed poorly on the persistence test. They simply didn't have the willpower left to resist slacking off.

The resulting paper, "Ego Depletion: Is the Active Self a Limited Resource?" inspired more than a thousand additional studies discussing everything from the influence of positive messages to the ego-sapping power of daily decisions [source: Villarica].

Studies also show that cognitive capacity also affects our ability to hold out against temptation. Cognitive capacity is essentially your working memory, which you employ when resisting a temptation ... or holding a string of numbers in your head. A 1999 study from then University of Iowa professor Baba Shiv found that people tasked with remembering a two-digit number held out better than people remembering a seven-digit number when tempted with chocolate cake [source: Raskin]. The idea was that if you distract the brain with a more difficult task (memorizing seven instead of two digits), it would be harder for participants to also make a healthy food choice.

Cognitive load and ego depletion produce similar effects on human willpower. Luckily, as we'll discuss on the next page, there are ways to recharge.

Baumeister's groundbreaking study was something of a downer with its talk of "a potentially serious constraint on the human capacity for control ..." On the other hand, it also presented willpower as something like a muscle. Use it too much and, in the short term, you wear it completely out. In the long term, however, the practice makes you stronger [source: Carr].

That's all well and good in the long term, but what about right now? Isn't there a way to boost our faltering resolve as the villainous cupcakes and sleazy neon signs close in on us? According to Baumeister and "Willpower: Rediscovering the Greatest Human Strength" cowriter John Tierney, we can always turn to our good friend glucose.

Glucose is a simple sugar found naturally in various plants -- and somewhat unnaturally in various snack items. It tastes great, sure, but it also energizes the body and brain. The writers say that a shot of sugar in the form of a quick juice box partially restores willpower (as well as cognitive capacity), much like a power-up in a video game.

But don't start stockpiling granola bars just yet! According to Stanford University psychologists Gregory M. Walton and Carol Dweck, our belief system also plays a vital role in how long our willpower holds out against desserts and decadence. The Stanford duo, along with psychologist Veronika Job, found that test subjects on the lookout for signs of willpower fatigue tended to slack off when they felt their resolve wavering -- while people who felt their resolve was limitless pressed on, wearied but relentless [source: Walton and Dweck].

These experiments provide a little insight into the mind-body connection -- that it's not merely a Platonic case of rational intellect versus base urges. A shot of sugar can help the restore diminishing will, but so can the intense belief that willpower is inexhaustible. Maybe a little of both strategies provides the perfect strategy.

Either way, we arrive on the shores of another fascinating question: Do some people possess more willpower than others?

In the lab, researchers measure willpower based on people's persistence with a given task -- be it solving a puzzle or abstaining from a chocolaty delight. Beyond this method, there's no universal measurement for human will.

Individual levels of willpower fluctuate throughout the day depending on diet, activities and other factors. Still, some folks experience a definite advantage. Roy Baumeister contends that there's likely some genetic component to human willpower, as self-disciplined parents tend to have self-disciplined children, but upbringing undoubtedly plays a strong role here as well [source: Economic Times].

This is where the marshmallows enter the picture. During the late '60s, the Stanford Marshmallow Experiment placed children ages 4-6 one at a time at a table in front of a tempting marshmallow. They were free to eat the alluring sugar puff, but there was a catch: If they resisted eating the marshmallow for a whole 15 minutes, they'd earn a second marshmallow.

As you might expect, most of the children broke after less than three minutes. The marshmallow was simply irresistible. Yet some of the children held out the entire 15 minutes, and these children went on to snag SAT scores 210 points higher than their sugar-happy counterparts [source: Lehrer]. The marshmallow gobblers, on the other hand, struggled with stress, relationships and attention as adults [source: Lehrer].

Since 1968, researchers have conducted various takes on the marshmallow test. For instance, a 2012 version from the University of Rochester primed the children to feel they were in ether an unreliable or reliable situation before the marshmallow test. Half the kids experienced a broken promise from a tester regarding additional art supplies, while the other half actually received them. When it came time for marshmallows, the rewarded children held out four times as long than the spurned children on eating the treat [source: Severns].

A new riff on the marshmallow test suggests kids will wait longer — on average twice as long — for that second marshmallow if they have good reason to believe that it will actually come.

So what are we to make of willpower? Some of us possess more than others, but it's a finite commodity. We can press on through ego depletion fatigue and believe ourselves inexhaustible. We can boost ourselves with sugary snacks. We can make deals with ourselves concerning long-term rewards. Or we can even threaten ourselves with punishments for failure, lashings ourselves to the figurative mast in what we call a Ulysses pact.

In the end, however, it's just you and the thing you simultaneously desire and loathe. So set obtainable goals. Remain conscious of limited willpower reserves, yet don't fall back on it as an excuse for caving.

But if all else false, just remember the words of Oscar Wilde:

"The only way to get rid of a temptation is to yield to it."