BY MICHAEL BLANDING
You’ve done everything—endured diets, purged your freezer of Ben & Jerry’s, and educated yourself on fat, sugar, and calories. Yet, you can’t manage to lose weight.
What’s wrong with you? According to standard economic theory, which gives humans (perhaps too much) credit for making rational choices, those efforts should be enough to change your behavior. If you know the consequences but still get fat, you must want to be overweight.
Of course not, say
Leslie John and
Michael Norton, professors at Harvard Business School specializing in the burgeoning field of behavioral economics. “Standard economic theory suggests that as long as people understand the full consequences of their actions, they tend to act in their self interest,” says John. “If they want to be healthy, and you tell them how many calories are in a burger, then they’ll eat better.” But behavioral economics suggests that people make mistakes in their thinking. For example, we have self-control problems that can lead us to knowingly “misbehave.”
Such biases are the bread and butter of behavioral economics, and have been accepted into the mainstream of economics and pop culture, particularly since the recent publication of popular books such as Richard Thaler and Cass Sunstein’s Nudge, Dan Ariely’s Predictably Irrational, and Daniel Kahneman’s Thinking, Fast and Slow.
Even so, relatively few companies have attempted to use behavioral economics to try to change people’s behavior around overeating, smoking, or other bad habits many are desperate to break. That’s why John and Norton are so intrigued by a company called StickK.com (pronounced “stick”), launched by two Yale economics professors who partnered to lose weight, and in 2008 turned the effort into a commercial
website and app.
Here’s how StickK works. The user selects a goal—like losing weight—and pledges a certain amount of money toward achieving it. Then a referee—often a friend—is chosen and a contract signed. If the goal is achieved, the participant gets the money back; if the goal is not achieved, they forfeit their pledge to a friend or charity.
The reason the strategy works, says Norton, is that instead of prohibiting behavior, as most diets do, it allows users to continue their behavior if they want to—but also sets up consequences.”The best interventions preserve freedom of choice,” says Norton. “I haven’t prevented you from gaining weight or removed all of the French fries from the world.”
At the same time, the strategy uses people’s biased thinking against them. For example, behavioral economics has shown that people tend to be overly optimistic about their sense of control—which is one of the reasons that they overeat in the first place. In the case of StickK, however, that optimism causes people to set overly ambitious goals, for example, about the amount of weight they can lose.
Once they are “on the hook,” however, the company makes use of another common bias in people’s thinking: loss aversion. Research has shown that people are much more averse to losing something they have than they are inclined toward gaining something they don’t. So by putting up their own money toward their goal, they try extra hard to avoid losing it.
“Losing $100 is more painful than gaining $100 is pleasurable, so that fear of losing money is actually a motivation,” explains Norton. In some cases, users even commit to send the money to a charity they hate if they fail at their goal—providing extra incentive. “You combine people’s belief that they can lose 10 pounds a month and couple it with loss aversion, and you put people in a position where they’re more likely to go out and exercise.”
StickK has incorporated another economic principle—the power of social norms—to keep people on track. Users create an online support network of family and friends who cheer them on.
Healthy Success Rate
According to StickK’s internal analysis of 125,000 contracts, this powerful combination of factors dramatically increases the chances that people meet their goals. When users sign contracts without naming a referee or putting money on the line, their success rate is 29 percent; when they put skin in the game, it rises to 80 percent.
Those findings resonate with John and Norton’s research, which demonstrates similarly powerful effects from applying behavioral economics principles to behavior change.
In a
study that John and several colleagues conducted on weight loss, published in the
Journal of the American Medical Association in 2008, participants were placed into one of three conditions—in the first case, people merely promised to lose 4 pounds a month; in the second, they wagered up to $90 of their own money, and if they lost the weight, they got their money back along with matching funds.
In the third case, participants were entered in a lottery that had a 5 percent chance of winning $100—but they would only win if they had met their weight loss goal for the month. This enticement took advantage of another behavioral economic principle: People overestimate small probabilities, a familiar truth to anyone who has ever bought a lottery ticket. “On average people won $5, but the possibility of winning $100 was far more motivating than just giving people that $5,” says John.