The Science of Willpower

UPDATED: May 22, 2023
PUBLISHED: March 25, 2014
The Science of Willpower

If you feel like you move through your days with the devil of temptation on one shoulder and the angel of restraint on the other, there’s good reason. A recent study shows we experience some sort of desire during one out of every two minutes we’re awake, and many of these are cravings we’re trying to resist. At day’s end, we have spent three to four hours using willpower to squash the urge to eat another cookie, take a nap, order a third martini, play Candy Crush, check in again on Facebook, buy another pair of shoes, lease a Tesla or have an affair.

So how do we fare in this war of willpower? Not that great. Roy Baumeister, Ph.D., a social psychologist at Florida State University, is one of the authors of the study, which equipped people with beepers that went off randomly seven times a day, cueing them to report whether they were in the throes of temptation. After compiling more than 10,000 reports, the tally showed that people succumbed to about one in six desires despite trying to resist. We’re pretty good, Baumeister says in his book Willpower: Rediscovering the Greatest Human Strength, in bucking extra naps, extramarital sex and overspending; less successful in resisting food; and dismal at standing firm against modern scourges of productivity—surfing the Internet, checking email or social media websites, watching television.

The capacity to say no—to the siren call of brownies, a midday snooze, a sale at the mall—is what Stanford psychologist Kelly McGonigal, Ph.D., calls “I won’t” power. But there’s more to willpower. Saying yes to what needs to get done and climbing out of a warm bed to go to the gym, tackling a difficult work project and sticking with it when you want to quit—this is “I will” power. “It’s the ability to find the energy, motivation and stamina to keep going even when you’re tired and anxious, and some part of you is looking for an escape,” says McGonigal, author of The Willpower Instinct: How Self-Control Works, Why It Matters, and What You Can Do to Get More of It.

Beyond these two sides of self-control is “I want” power. This is the ability to keep your eye on the big picture and tap into your priorities beyond the short-term gratification of a Snickers bar or blowing off a networking event to catch up on Homeland.

“I define willpower as the ability to choose what matters most,” McGonigal says, “even when it’s difficult or when some part of you wants to choose something else.” And Baumeister says willpower is the surest way to a better life.

So harness the “I will, I won’t and I want” components of willpower for an essential tool in achieving your goals.

The Willpower Shortage

Most of us believe we don’t have enough willpower. In the American Psychological Association’s annual surveys on stress, people regularly cite lack of willpower as the No. 1 barrier to following through on changes that would improve their lives. And willpower is a limited resource. Study after study shows 1) we deplete our willpower reserves as we call upon them and 2) we call upon willpower constantly.

Consider a study in which Baumeister brought college students who had fasted for several hours into a room filled with the aroma of just-baked chocolate-chip cookies. Near a plate of cookies was a bowl of radishes. Before being left alone, one group was invited to enjoy the cookies and the other group was given permission to eat only the radishes. As Baumeister and colleagues watched through a one-way window, the radish nibblers visibly struggled with temptation, some picking up a cookie to inhale its fresh-from-the-oven smell. Then both groups were given 30 minutes to complete an impossible geometric puzzle. The result: Radish-eaters—who had already faced the daunting task of resisting the cookies—gave up after about eight minutes; cookie eaters persisted for an average of 20 minutes.

Other studies replicated these results: When people exerted willpower on one task, they had less self-control on the next—whether it was holding their hand in ice water, suppressing sobs while watching a tearjerker or stifling giggles during an Eddie Murphy video.

Every act of willpower draws on the same currency, leaving us with less to spend on the next self-control challenge. And we exert willpower dozens of times a day, when we repress an impulse (say, to curse the driver who cut us off) and filter out distractions like the construction racket outside our office. It takes willpower to control thoughts and feelings and stay alert during a long meeting. What’s more, the same energy used for self-control is spent in making decisions, even inconsequential ones. You expend willpower when pondering which yogurt to buy from among 40 varieties offered.

Willpower is not a cheap resource. Exerting self-control, McGonigal says, is one of the brain’s most energy-expensive tasks, sapping more blood sugar, or glucose, than memory or language chores. In one experiment, participants watched a video in which words flashed across the bottom of the screen. Some were told to ignore the words; others weren’t given this instruction and were free to relax while viewing the video. Afterward, blood sugar levels had plunged among the people who exerted self-control ignoring the flashing words but remained steady in the relaxed viewers.

Follow-up experiments showed that when glucose was restored with a glass of sugar-sweetened lemonade, willpower was replenished and performance on self-control tasks improved. The takeaway: One defense against a willpower scarcity is to avoid glucose dips. A sugary drink works in the lab but isn’t a healthy or effective long-term strategy. A smarter plan is to maintain stable blood sugar with a diet of low-glycemic foods such as non-starchy veggies, fruit, nuts, beans and whole-grain products. (This plan may help you lose weight, too.)

Reducing unnecessary withdrawals can also help you avoid willpower bankruptcy. President Obama uses this strategy. He wears only gray or blue suits—one way, he told Vanity Fair, to pare down decisions. “I don’t want to make decisions about what I’m eating or wearing, because I have too many other decisions to make. You need to focus your decision-making energy. You need to routinize yourself. You can’t be going through the day distracted by trivia.”

Psychologists recommend a willpower-conserving technique called “implementation intention” or “if-then” thinking that sets up a specific plan to deal with probable temptation, such as fattening food at a party. An implementation intention might be, “If they serve chocolate cake, I’ll stick with fruit.” Or you can use implementation intention as way to pre-commit to goals. “When the alarm goes off at 6:30, I’ll change into the workout clothes I laid out the night before and go for a 3-mile run.” Caroline Adams Miller, a life coach and co-author of Creating Your Best Life: The Ultimate Life List Guide, says she trains clients in the technique with remarkable success. “The idea is to make as many behaviors as possible automatic,” Miller says, “so you don’t exhaust yourself trying to make new habits every day.”

Building a Bigger Brain

Behind your forehead and eyeballs is a squiggly brain region called the ventromedial prefrontal cortex. We use this gray matter when deciding whether to reach for a cookie or crudité. People who make the healthy choice also activate a nearby part of the brain, a clump of cerebral cells called the dorsolateral prefrontal cortex.

You can make these willpower centers of your brain denser and better connected to each other. Meditation, neuroscientists have discovered, leads to better focus and self-control after just three hours of practice. And after 11 hours of meditation, MRI scans show that novice meditators have increased neural connections and gray matter in brain regions responsible for impulse control. With daily meditation, McGonigal says, people can turn their brains into “finely tuned willpower machines.” You can begin a brain-training meditation habit with just five minutes a day, focusing on your breath as you sit still. When your mind wanders—and it will—bring it back to the breath. If you find yourself constantly distracted by random thoughts, congratulations. Being “bad” at meditation—constantly needing to push away intrusive thoughts—is what trains the brain and strengthens willpower, McGonigal points out.

Physical exercise also cultivates the gray matter needed for self-discipline. Small bursts of brisk movement—a fast-paced five-minute walk several times a day—are all you need to boost self-discipline. “In as little as a few weeks,” McGonigal says, “you can change your brain so the version of you who is walking around in the world making choices is more likely to be the version of you who remembers what your big goals are.”

The Spillover Effect

Roy Baumeister offers one piece of advice for anyone intent on self-improvement: Skip the New Year’s resolutions. Inevitably that long list of goals will be abandoned by February. The willpower depletion theory demonstrates we have only enough self-control to tackle one big change at a time. Try to quit smoking while you attempt to lose weight, and you’ll probably fail at both.

But there’s a heartening flipside to this advice. Willpower has a spillover effect. If you practice self-control in one area, you’ll probably experience improved self-discipline in others. In an Australian study, people were given free gym memberships and training. After two months, those who stuck with the program reported improvements in almost every other area of their lives: They were smoking and drinking less, eating healthier, and were less likely to leave dishes in the sink, overspend, lose their tempers or procrastinate.

Another recent study, this one at the Weight Control and Diabetes Research Center at The Miriam Hospital in Providence, R.I., suggests you can train yourself to have more willpower. Research participants were asked to squeeze a spring-loaded handgrip as long as they could—a common test in willpower studies—before they began a six-month weight loss program. They repeated the handgrip test at the end of the program.

Researchers found that participants who had dropped at least 10 percent of their weight by sticking to the low-calorie diet, showing up for weekly meetings and maintaining an exercise regimen also had improved the most on the handgrip test. What surprised lead investigator Tricia Leahey, Ph.D., is that stamina level at the beginning of the study had no effect on weight loss. Those with the greatest willpower (superior handgrip stamina) early on didn’t lose more weight than others. “It doesn’t matter where you are on willpower when you start a weight-loss program. You can actually change your level of self-control with practice,” Leahey says.

Whether the temptation is cream puffs or procrastinating, it’s profoundly human to struggle with self-control. “We are both the versions of ourselves who can pursue our big goals and we are also fundamentally someone who is always going to be distracted and tempted,” McGonigal says. “When you recognize that the strength to make changes does not require getting rid of that other part of yourself, it’s incredibly empowering. You can be anxious or tired and still take positive action. You can experience cravings and say no. Willpower isn’t about being some kind of miraculous human who never struggles with temptation.”

Learn six simple changes that can fortify your willpower reserves.