Hungry? Don’t Go Shopping.

Hunger is one of our most basic and primitive drives. When we are deprived of food, for whatever reason, we become intensely focused on satiating that craving. We want calories, and we want them now. Everything else—including time and money—is merely an aid for finding and acquiring rich, caloric food.

This makes sense. It’s survival. Yet beyond this fundamental drive for satiety and nutrition, surprisingly little is known about hunger’s influence on our behavior.

New research suggests that hunger’s power may extend beyond eating and nutrition, indeed that it may influence judgments and decisions completely unrelated to those stomach pangs. A team of psychological scientists—Allison Jing Xu of the University of Minnesota, Norbert Schwarz of USC and Robert Wyer of the Chinese University of Hong Kong—wondered if hunger might spill over into other behavioral domains, sometimes in irrational ways. Is it possible, that is, that hunger triggers an acquisitive mindset generally, one that piques our desire even for non-food?

The scientists explored this provocative idea in several experiments. In one, for example, they recruited subjects during lunchtime, at a café. Some were on their way to eat, while others had already eaten and were on their way out. The subjects rated their hunger, and then completed a survey, in which they rated how much they wanted to acquire certain products, and also how much they liked those products. Some of the products were food items—sandwiches, pasta—while others were not food—a flash drive or a spa visit.

So the scientists were looking at hunger’s effect on four things: desire to acquire food, desire to acquire nonfood, liking for food, and liking for nonfood. Not surprisingly, subjects liked the food choices more before eating than after. But eating did not affect their liking for nonfood items. By contrast—and this is the key finding—hungry subjects were more acquisitive regarding both food and nonfood. So it appears that hunger triggers a broadly acquisitive mindset—an intention to get stuff—without actually affecting the liking of this stuff.

Intentions are one thing; behavior another. So in another experiment, the scientists explored actual acquisition. They showed a group of volunteers a binder clip, the kind one finds in the supply room, and asked them how many they wanted. They also asked them how much they liked or disliked the binder clips, and how hungry they were. Hunger was unrelated to how much the volunteers liked the clips, but hunger nevertheless influenced how many clips they chose to acquire.

Think about this. Nobody craves binder clips. They’re not really satisfying or interesting in any way; they’re just stuff. Yet hunger made these volunteers act like this common office item was something worth acquiring. This acquisitive mindset remained influential even if people had to pay for stuff. In yet another study, the scientists scanned the actual shopping receipts of shoppers leaving a large department store. Hungry shoppers purchased more stuff and spent more money than less hungry shoppers. This irrationality leads the scientists to conclude that a fundamental, biologically-based motivation affects behavior that is totally unrelated and incapable of satisfying the true need.

Episodes of mild hunger are not uncommon, even in affluent societies. Many people say they skip meals regularly, and millions are dieting at any given time, depriving themselves of calories every day. People also make unplanned purchases all the time, deciding on impulse that they need a new pair of shoes or a new set of golf clubs. This new scientific evidence, reported this week in the Proceedings of the National Academy of Sciences, suggests it may be worth exploring a possible connection between eating and shopping.

Follow Wray Herbert’s reporting on psychological science in The Huffington Post and on Twitter at @wrayherbert.