I Know, Rob...Portion Control

Late last year, a little book called “Mindless Eating” started appearing in bookstores. It was written by Brian Wansink, a Cornell professor who has spent his career doing brilliantly mischievous experiments about the psychology of eating.

In one of my favorites, Mr. Wansink gave away five-day-old popcorn — “stale enough to squeak when it was eaten,” he wrote — to moviegoers one day at a theater in the Chicago suburbs. The crux of the experiment lay in the size of the buckets that held the popcorn. Some people got merely big buckets, while others received truly enormous ones. Both sizes held more popcorn than a typical person could finish.

Yet when the Wansink research team weighed the buckets after the movie, there was a huge difference in the amounts the two groups ate. Those with the bigger buckets inhaled 53 percent more on average, suggesting that a lot of stale popcorn is somehow more appealing than a little stale popcorn.

Over the years, Mr. Wansink has done similar experiments with everything from different-size dinner plates to bottomless bowls of tomato soup that are secretly connected to a tube underneath a restaurant table. His overarching conclusion is that our decisions about eating often have little to do with how hungry we are. Instead, we rely on cues like the size of a popcorn bucket — or the way we organize our refrigerator — to tell us how much to eat. These cues can add 200 calories a day to our diet, but the only way we’ll notice we are overeating is that our pants will eventually get too tight.

Over the last couple of decades, a new field of economics, behavioral economics, has emerged to explain why people so often act in ways that are contrary to their own interests. They overeat, smoke, forget to take their medicine and don’t save enough for retirement, saying all the while that they wish they could change. Figuring out how to turn these wishes into action could put a dent in some big social problems.

This study, though, is related to more than just eating. It's related to the commonsense idea that the context in which a choice is presented might be the most important factor used to make decisions. We see this in manufacturing, too. I've heard stories of appliance makers who create two models: one really expensive one that they don't expect to sell many of, and one less expensive model that looks like a bargain in comparison. Check it out the next time you're shopping. It's pretty bizarre.

Though lessons learned from behavioral economics can be used to manipulate us to go against our own better judgment, they can also be used to trick us into doing ourselves a favor.

Last year, President Bush signed a new pension law that was based in part on this idea. It gave companies an incentive to sign up workers automatically for 401(k) plans. The workers can still opt out; in fact, they have the same range of choices they have always had. But if they do nothing, a small part of their salary is set aside for retirement.

The pension bill sprang directly from academic research showing that automatic plans vastly increased the amount of money that people saved. “It’s the success of behavioral economics, by far,” Daniel Kahneman, the Nobel Prize-winning psychologist who helped found the field, recently told me.

Whether it’s 401(k)’s or food, the way choices are presented to people — what the economist Richard Thaler calls “choice architecture” — has a huge effect on the decisions they make.

Read the entire article here.