That kind of illogic—the drive to eat something painful or even something we don't like very much—offers Rozin endless fodder for study. We may have the same physiological mechanisms as a rat or a goldfish that tell our bodies to maintain a certain weight and take in certain nutrients, but in humans those have become buried beneath the weight of our desires, our cravings, the machinations of our conflicted brains.
We certainly don't just eat when we're hungry and stop when we're full; we eat because it's "time to eat" or because it would be rude not to, regardless of whether or not we feel hungry. That disconnect, says Rozin, is a central construct of American eating. "People misread their own desires all the time," he says. For instance, many people prefer to buy variety packs of items like breakfast cereal or snack foods, even though they dislike some of the items that are included. "Why don't they just buy the kind they like?" Rozin asks. "Because people reliably think they will like more variety than they actually do."
The jelly bean test shows the same thing: The more flavors of jelly beans people are offered, the more they'll eat, regardless of whether they're mixed together or separated by flavor. "Seeing the different types creates the desire to try them all," Rozin explains. Therein lies food marketers' greatest weapon: Offer people greater options, and they will consume more.
The appeal of a plethora of choices is very American—a distinction that is providing much of the direction for Rozin's research these days. Think of a typical diner menu that offers everything from omelets to Greek salad to meatloaf and mashed potatoes, or even a higher-end restaurant that features ten or 20 entrées. "In a French restaurant," Rozin says between bites of the meat pie he's now working on, "you get far fewer choices. They don't feel they have to cater to every little food preference someone might have."
One of Rozin's collaborators recently put this cultural difference to the test, asking people in the United Kingdom, Italy, Germany, France, Switzerland, and the United States one question: In an ice cream parlor, do you prefer to be given 10 or 50 flavor choices? The only country in which the majority said 50 was the United States. "Constantly choosing is the American way," says Rozin, who is himself bemused when he encounters evidence of the American mania for quantity over quality. "I went to one of those smoothie chain stores recently. I looked at the menu and realized there were about 6,000 different drinks you could order—there were eight different juices, five 'boosters,' yogurt or no yogurt, and you could make any combination of all these things." Rozin proceeded to frustrate the person behind the counter by refusing a free shot of a vitamin booster. "In America, if it's free, you take it, whether you want it or not! That's the rationale behind supersizing—it's not exactly free, but it's a lot more food for very little more money. That's irresistible."
Where Americans find their pleasure is what Rozin has recently been trying to parse out, and while using a theory developed by Daniel Kahneman, he has come up with a kind of psycho-algebraic pleasure equation. There are three species of pleasure, he explains: anticipatory pleasure, when you're looking forward to something; actual pleasure, which happens in the present moment; and remembered pleasure, reliving the experience afterward. The mathematical laws of pleasure, as he's worked them out, dictate that if you maximize anticipatory or remembered pleasure, you usually minimize another.