hard habit to break?

The Behavioral Economics Diet: The Science of Killing a Bad Habit

What really motivates you more, the promise of a reward if you succeed or a debt if you don’t?

Nir Eyal

Diets don’t work. Studies show that temporary fixes to old habits actually make people gain weight. Essentially, the dieter’s brain is trained to gorge when off the diet and inevitably the weight returns.

In my previous essay, I shared the story of my father's struggle with bad eating habits. He had put on weight over the last few decades and despite several attempts, he had trouble taking it off. In his late 60s he faces pre-diabetes and a daily ritual of taking a handful of pills.

But over the last five months, something has changed. He’s found a new way to resist the temptation of the food he’s been trying to stop eating for years.

We Took a Bet

My father and I shook on a $25,000 wager that binds him to never eat refined carbohydrates again — no processed sugars, no processed grains. Many people are shocked by the dollar amount of the bet but that’s missing the point. My objective is to never win the money. The bet just has to create a moment of consequence to disrupt the current habit with an amount large enough to be meaningful.

So far it’s working. My father has lost about 2 pounds per week and his improved blood work convinced his doctor to take him off some of the meds.

Why It Works

Admittedly, my father is just one person.  His story provides little more than anecdotal evidence. However, a study published in the New England Journal of Medicine provides some supporting evidence that putting some skin in the game makes people more likely to accomplish their goal of stopping a bad habit.

The study followed three groups of people trying to quit smoking. The control group was offered information and traditional methods for smoking cessation like free nicotine patches. After 6 months, 6% of the people in this group stopped smoking. The next group, called the “reward” group, was offered $800 if they were smoke-free at 6 months. Of those, 17% quit. From just these two groups, we see paying people does indeed provide an incentive to stop a bad habit, at least short term.

However, the third group provided the most interesting results. In this group, called the “deposit” group, participants were asked to put down $150 of their own money, which they would receive back if they successfully quit in 6 months. In addition, they were given a $650 bonus prize from their employer if they quit. Of those who accepted the deposit challenge 52% succeeded.

On the surface, this makes no sense. Why would winning $800 be less effective than winning only $650 plus $150 of your own money back?

Perhaps people in the deposit group were more motivated to quit smoking in the first place? The researchers admitted that over 85% of people who were offered the deposit deal refused to take it. However, the study authors took efforts to scrub the effect of extra motivation by only using data from smokers willing to be in either group.

Loss Aversion, Commitment, and a Social Out

So what else might explain the results? For one, the study authors write, “people are typically more motivated to avoid losses than to seek gains.” This irrational tendency, known as “loss aversion,” is a cornerstone of behavioral economics. As Nudge author Cass Sunstein, wrote, “a 5-cent tax on the use of a grocery bag is likely to have a much greater effect than a 5-cent bonus for bringing one’s own bag.”

There are other factors at work as well. Commitment contracts — like putting money down or taking a bet — have proven to be effective at changing behavior because they make us accountable to our future selves. People are notoriously bad at predicting their behavior due to a phenomenon called “time inconsistency.” Essentially, we punt difficult to do behaviors saying, we’ll “eat better tomorrow” or we’ll “clean the garage” next weekend.

Tim Urban, author of the Wait But Why blog, explains his struggle with procrastination writing, “I banked on Future Tim’s real-world existence for my most important plans, but every time I’d finally arrive at a time when I thought I would find Future Tim, he was nowhere to be found — the only person there would be stupid Present Tim. That’s the thing that really sucks about Future You — whenever time finally gets to him, he’s not Future You anymore, he’s Present You, and Present You can’t do the tasks you assigned to Future You … So you do what you always do — you re-delegate them to Future You, hoping that next time time catches up with Future You, he actually exists.”

By creating a binding commitment — like the $25,000 bet my father took with me — we make sure our future selves behave in line with our present goals. A website called stickK.com uses commitment contracts to help its’ users accomplish their goals. People sign legally binding agreements where they have to pay a third party if they don’t meet their obligations to stop smoking, exercise, or finish their novel, for example. The site, founded by two Yale professors, has proven effective for those brave enough to take the bet.

There’s one more important and often overlooked reason these types of commitments work — they change the language we use. When I asked my father how he manages the temptation to not cheat with just a bite of cake now and then, he told me, “I just don’t. It’s actually not a big deal any more.” Frankly, I was surprised he is having such an easy time with it. Here’s a man who has struggled with his weight for over 30 years but who suddenly finds giving up some of his favorite foods to be, well, a piece of cake. What gives?

It turns out that the way we describe our behaviors can have a dramatic impact on what we will and won’t do. A study in the Journal of Consumer Research found that people who were prompted to use the words “I don’t” versus “I can’t” were nearly twice as likely to resist the temptation of choosing unhealthy foods. The researchers believe using “I don’t” rather than “I can’t” gave people greater “psychological empowerment” by removing the need to make a decision. “I don’t” is outside our control while “I can’t” is self-imposed.

Now when my father goes out to lunch with his friends and dessert is brought to the table, he has a story to tell. “When they offer me a bite, I let them know it would be a very expensive mouthful,” he said. “I explain I just don’t eat that stuff anymore because the bet I made is for life.” He explains, “When I tried to lose weight before, I had to explain to people that I was on a diet. Eventually, I would get tired of saying ‘I can’t’ and I’d cave-in and tell myself, ‘just this once.’ But now with this bet,” my father joked, “I can just blame you!”

Here’s the Gist:

- Creating a commitment to stop a bad habit can increase the odds of quitting certain behaviors.

- Though not appropriate for all behaviors (I discuss the limitations in my next essay), the technique works because it uses loss aversion, a commitment contract, and provides a social out for not doing the behavior by changing the language we use to describe our actions.

This post originally appeared on Nir Eyal and was published May 26, 2015. This article is republished here with permission.