After the task, subjects from both groups were allowed to eat “ad libitum” —which happens to be my favorite way to eat—from a bowl of M&Ms. As the researchers had guessed, the people who had imagined eating thirty M&Ms ate measurably fewer real M&Ms than those who had only imagined eating three.
A follow-up experiment demonstrated that in order for repeat exposure to a food stimulus to satisfy appetite, rather than stimulate it, you have to imagine actually eating the food. Half of a new group of participants were told to imagine putting M&Ms into a bowl. The more candies they imagined handling, the more real M&Ms they ate afterward when given the chance. But as in the first round, a separate group of subjects were told to think about putting the M&Ms in their mouth, and they ate fewer real ones if they'd imagined eating more.
The researchers went on to demonstrate that the satiation caused by imaginary eating is specific to the food that's being imagined. Subjects who were asked to imagine eating cubes of Cheddar cheese ate fewer real ones if they'd first imagined eating thirty cubes rather than three. But subjects who imagined eating either three or thirty M&Ms showed no difference in how much Cheddar they ate afterward. In a final experiment, they showed that the process by which imagination satisfies appetite has to do with the appetite drive itself, not by reducing how much a person thinks they like the food in question.
The CMU psychologists' study sheds light on cognitive processes that have been hotly debated, and received wide notice. But the authors also noted practical uses of learning that “participants who imagined consuming more of a food were subsequently less motivated to obtain it than were participants who imagined consuming less of the food.” They concluded, on a hopeful note, that besides its “theoretical importance, this finding may allow for the development of more effective interventions to reduce cravings for unhealthy food,” and could also help treat drug addiction and phobias.
Social influence is another obvious dimension to our enjoyment of food. It's common for tastes and smells to trigger emotions that recall far-off or long-ago family, friends and places. But social tools like Facebook, Flickr, Twitter and Instagram have allowed anyone who likes (which turns out to be a lot of people) to share meals electronically. In an April 2010 story, The New York Times noted the growing popularity—bordering on compulsion, according to some—of photographing and blogging about every meal out.
Soraya Darabi, cofounder of the food-centered social mobile application Foodspotting, doesn't see signs of an overindulgent food craze in the rise of online food-sharing communities. Darabi says that while Foodspotting didn't explicitly design itself to promote healthy eating, they've found that taking pictures of meals and sharing them makes users “more aware of portions,” which she identifies as the most critical factor in maintaining a healthy weight. (Last month, Foodspotting acquired Eat.ly, another food-sharing community, where users can rate meals on a one-to-100 healthiness scale.) At Foodspotting events, Darabi notes that she has “yet to encounter a member who is overweight,” and observes that among food editors and writers—the people most heavily immersed in food imagery—“the majority are extremely mindful of what they eat.” Rather than a celebration of indulgence, interest in learning about different foods is what cofounder Alexa Andrzejewski cites as the motivation behind all that sharing of food images.
Whether or not we seek them out, each of us encounters countless images of food—often tempting in inverse proportion to nutritional value—every day. It's easy to see them as a hazard to the weak-willed and a cause (or symptom) of a culture that has no trouble generating a steady supply of contestants for weight-loss reality shows like NBC's “The Biggest Loser” and A&E's “Intervention.” But the lab suggests that images of food can be made to satiate rather than stimulate appetite, and it's encouraging that online communities have shown that the act of documenting images of one's meals can lead to awareness rather than excess. By utilizing what would normally be considered secondary sensory experiences of food—visuals and memories of smell and texture—it's possible to better and more healthily enjoy the most obvious one: taste.
Peter Feld is a writer and Web content strategist who has written for publications including Cookie, Portfolio.com, Mugshot, Gawker and Advertising Age.