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The science of keeping your New Year’s resolution

Times Square in New York City. (Neilson Barnard/Getty Images)

Old habits die hard, and that’s particularly true of bad habits.

New Year’s resolutions, derided though they often are, present a big opportunity for self-improvement, according to research on human behavior. On New Year’s, we look back on past failures to change and feel an uncommon surge of optimism. We rationalize that it was “the old me” who failed to change, but this year will be different. A full 40 percent of Americans make New Year’s resolutions, and fortunately for them, social science has some insights into how to break a bad habit — or start a good one.

Start with a bang

Several years ago, a group of 120 students at the University of Chicago were recruited by two economists — Gary Charness and Uri Gneezy — to participate in an experiment about exercise habits. A randomly assigned third of the students were paid $175 for merely attending an information session and giving researchers permission to track their gym attendance. Another third got paid if they attended the information session, allowed their gym attendance to be tracked and went to the gym at least once in the next month. The final third of the students were paid for attending the information session, for allowing their gym attendance to be tracked and for hitting the gym at least eight times in the next month.

Unsurprisingly, the group who had to make eight gym visits to get paid exercised more than the other two groups. But what’s really interesting is what happened after all of the payments stopped.

The students who had just finished a month of unusually high exercise activity (the ones who had just earned $175 for working out eight times) kept going to the gym at a far higher rate than others. They worked out at the gym nine times in the following seven weeks, and the other students in the study went roughly half as often.

This illustrates that if we can get people (or ourselves) to try something new intensively for as little as a month (even with an instrument as blunt as a cash payment), we can kick-start lasting behavior change. So even if you can’t promise yourself to stick with something for long, there’s a huge benefit in putting in a burst of energy for a few weeks — it may pay off for longer than you think.

Take a mulligan (or two)

Many of us find it hard to stick to good behaviors all the time, which might suggest setting easy New Year’s resolutions to avoid the discouraging experience of failure — an experience that can lead us to give up on our goals.  On the other hand, research has shown that setting tough-to-attain goals is more motivating than setting easy ones.  So how can we balance these two facts?  A recent study may offer the perfect solution.

Two marketing professors — Marissa Sharif and Suzanne Shu — offered hundreds of people $1 for every day in a week that they remembered to go online and complete a set of 35 annoying tasks.  These wage-earners were then randomly assigned different goals and given a $5 bonus on top of their other earnings if they achieved their goal.

Some participants were randomly given the goal of completing their assignment seven days out of seven — a tough but achievable goal.  Others were randomly given the easier goal of completing their assignment on just five days out of seven but encouraged to aim to complete the tasks every day to maximize their earnings.  Finally, a “mulligan” group was given the goal of completing their assignment seven days out of seven but told “in case you need it, up to two days will be excused.” In other words, this “mulligan” group was only required to do the assignment on five days out of seven to earn their $5 bonus just like the easy goal group, but they had been given the tough stated goal of doing it every day of the week.  Remarkably, even though the “mulligan” group faced exactly the same incentives as the group with the easy target, they were significantly more successful: 53 percent of them earned $5 compared to 26 percent of the participants with the (identical) easy goal and 21 percent of participants with the seven day per week goal.  What this suggests is that the perfect goal to set for yourself is probably a tough one but with the explicit allowance for a mulligan or two so you won’t be discouraged by the occasional slip up.

Piggybacking and temptation bundling

Research points to the benefits of what’s called a “piggybacking” strategy. Piggybacking involves linking something you’d like to start doing regularly — like flossing or eating an apple a day — with something you already do regularly, like brushing your teeth or drinking a morning cup of coffee.  In one small study, people attempting to kick-start a flossing habit were more successful when they were prompted to floss after brushing their teeth rather than vice versa.

Related to piggybacking is an idea my collaborators and I call temptation bundling.  Temptation bundling means linking something you’d like to do more often with something indulgent that you crave.  For instance, imagine you love binge-watching “Game of Thrones” but feel guilty about doing this at home when you should be spending quality time with family. Imagine you’d also like to start a gym habit.  Your temptation bundle might be to watch “Game of Thrones” only when exercising at the gym.  You’d stop wasting time at home on TV and start craving trips to the gym to find out what happens in the next episode.  Not only that, you’ll enjoy “Game of Thrones” and exercise more together — you won’t feel guilty watching it, and time will fly at the gym.

In one study of 151 people who wanted to exercise more, we randomly assigned 75 to a temptation bundling group.  These people came to the gym for a workout and during it, they listened to the start of a tempting audio-novel of their choice (books like “The Hunger Games” or “The Da Vinci Code").  At the end of their workout, participants were told that if they wanted to hear what happened next in their novel, they would have to come back to the gym because their audiobook on a loaned iPod would be held in a locked, monitored locker at the gym for the next 10 weeks and they could only access it when exercising.  The other 76 participants in our study also completed an initial workout but without any kind of temptation bundle.

Over the next seven weeks, participants in the temptation bundling group visited the gym 27 percent more frequently than participants in the control group.  Sadly, the temptation bundling trick fell apart over the Thanksgiving holiday when the gym closed (so access to tempting audio-novels went away).  Forced separation is the best known cure for cravings, so maybe this isn’t surprising, but it means temptation bundling may not have the staying power to kick-start a habit that will last through all of 2018.  Still, it may be a useful trick for changing behavior particularly when combined with other tactics.

Katherine Milkman is a behavioral economist at the University of Pennsylvania who studies decision-making and how to improve it.