Mind Your Body: Doctors' Orders—Without Distress

When a young Israeli named Dan Ariely was burned by a military flare, doctors in Tel Aviv weren't sure he would survive. After three grueling years, he was released from the hospital, but his troubles were far from over. Ariely learned he'd contracted hepatitis C from a tainted blood transfusion. He joined a treatment program that was testing an experimental medication called interferon. Three times a week for a year and a half, he had to inject himself with a drug that plunged him into a 24-hour fit of fevers, headaches, shaking, and vomiting.

Of the 300 people in the treatment program, Ariely was the only one who took the treatment every time. His method, he explains, was to link the unpleasant task of injecting himself with a positive outcome. He loves movies, so he made a rule: He could watch a movie only after he'd injected himself. "It didn't really compensate for the horrific reactions of the medication," Ariely says. "But it worked."

Make a Plan (and a Plan B)

Getting people to do the things they need to do to keep themselves healthy is tricky. Humans are complex and fallible creatures. Modern medicine can work wonders, but only when we actually use it. Half of all patients don't take their medicine, and studies show that the sickest patients are least likely of all to follow medical instructions. We eat foods that kill us, we don't stick to our exercise regimens, and we don't follow our doctors' orders, even when we remember what they tell us. "If you ask people whether it's smart to get a colonoscopy if the doctor says you need one, no one's going to say no," says Ariely, now a professor of behavioral economics at MIT and author of the forthcoming book Predictably Irrational. "But no one wakes up and says, 'Yes, today is a good day for a colonoscopy.'"

The classic triumvirate of medical adherence, doctors say, comprises understanding what you're supposed to do, having the resources to do it, and wanting to do it. Your doctor needs to assess these factors, so it's important to be candid about your willingness to carry out a treatment. "Patients don't want to look stupid or noncompliant in front of the doctor so they'll often just nod blithely," says Jerome Groopman, a professor at Harvard Medical School and author of How Doctors Think. If you don't believe in a treatment and you're not going to follow it, say so. That way, you and your doctor can negotiate a compromise that will work for you.

Even when a goal is feasible and desirable, people still don't usually follow through, says Peter Gollwitzer, a psychologist at New York University. But Gollwitzer has found that when people form what he calls an "implementation intention"—a plan that says "if this happens, then I'll do this"—the success rate doubles. You might say, "If I get up in the morning, then I'll take a walk." That way, the situation (waking up in the morning) triggers the behavior (walking) automatically, without your having to think about it. It's also important to shield yourself from distractions and temptations that might arise along the way. This, too, is done by creating an if-then plan, such as, "If I walk by a cafe, then I will ignore it."

It's also important to plan for slipups. When people make a mistake, they tend to compound the error. It's known as the "what the hell" effect: You think, "Now that I've had one cookie, I'm no longer on my diet, so, what the hell, I may as well eat the rest." The solution is to plan for this, too, with another if-then plan, telling yourself that if failure mounts, you'll switch strategies. You might decide that if walking doesn't work because you always stop at restaurants, you'll start going to the gym instead. Again, you plan in advance, so no spot decision is required.

Keep Track

Externalizing your record of success and failure is also useful. Try keeping a written record of how much you exercise. Making public promises can help—announcing you're going to lose 30 pounds with all your friends present motivates you to actually do it. Or plan to exercise with a friend. Once you set a date, you're both obliged to show up. And a public bet can work well: You and a friend agree that every week, whoever has exercised more has to pay the other $100.

"The most important design feature is frequent monitoring, feedback, and rewards," says George Loewenstein, an economist at Carnegie Mellon. In a study of drug addicts, Stephen Higgens, a psychologist at the University of Vermont, created a program in which addicts received cash vouchers for every day they showed up and tested clean. The program has a high success rate because it rewards the addicts for every successful step, not just the attainment of a long-term goal.

Practice Makes Perfect

The good news is that the more you do what you're supposed to do, the easier it gets. Self-control works like a muscle: It gets stronger with use, according to work by Roy Baumeister, a psychologist at Florida State University. "The key point is that it's one muscle used for many different things," Baumeister says. "So anything you do to strengthen it will be helpful in the long run."

As for Ariely, his health is now excellent. His virus counts are low and the disease is well under control. Meanwhile, two of his friends made a bet about who could lose more weight by the end of the year. They were competitive enough that they knew they would actually take the money from each other. Their bet? Both were Ph.D. students, and they wagered a third of their yearly stipend. "That's pretty radical," Lowenstein says. "I don't know if most people would need to do something quite so severe."

Swallowing a Bitter Pill

Link difficult tasks to positive outcomes.

Give yourself a treat when you do something right.

• Pay yourself. Give a friend $1,000. Every day you eat healthfully (or exercise, or take your medicine), you get $50 back. For every day you miss your target, your friend donates your $50 to your least favorite political party.
• Create if-then plans. Making an if-then plan—if I get off work, then I'll go straight to the gym—makes behavior automatic so there's less chance you'll slip.
• Compete. Setting up a contest with a friend—such as agreeing that whoever loses more weight has to pay the other—can add competitive fuel to your motivational fire.
• Watch your stress level. Willpower is a limited resource, so be extra vigilant during stressful times, when it may be depleted.
• Use external monitoring. Keep a written record of how well you're doing. Or better yet, get someone else to keep track for you.
• Make social contracts. The buddy system is
  powerful. Find a friend in the same boat and make an appointment to work on your task together.