Hunger is a part of daily life. Before each meal, it beckons us to the table and reminds us that our existence depends on putting food in our mouths. Hunger is so universal that a complete trilogy of young adult books and movie spinoffs take their name from the sensation. Hunger stems from a lack of food, but it can represent the yearning for something else entirely. Metaphorically speaking, we can say we hunger for knowledge, for recognition, for new experiences (or freedom from the Capitol). 

But new research shows there’s more than metaphor at work in these sayings. Hunger can make us crave things other than food. Besides crankiness and a need to find a kitchen, hunger’s effects include a stronger desire for mundane objects like stationery. People who are hungry even seem to shop more at the mall.

These findings may have implications for anyone who’s ever tried to modify their diet, which is increasingly common in a country where two thirds of adults are overweight or obese. We should be aware of hunger’s subconscious effects on our judgment. Do I really want to buy this pillow, or am I just hungry?

Researchers asked participants to fill out a questionnaire about mood, hunger, relaxation, and binder clip preferences. The participants were then given actual binder clips (the 3/4 inch variety, to be exact) and asked some strange questions: “Do you think this binder clip is easy to use?” and “How much do you like this binder clip?” After fiddling around with the clips, the probably mystified participants were asked how many they wanted to take home.The results: hungrier people requested more binder clips. Somehow, it seemed that hungry people wanted not just food, but nonfood items as well.

Hunger is a complex phenomenon. Judges seem to mete out harsher sentences if they haven’t taken enough breaks, possibly because they are hungry. And while it might seem reasonable that hungry people see food as more appealing, especially foods high in calories, hungry men also find pictures of heavier women more attractive. Hunger might simply befuddle us, or it might plug into the primordial need to acquire.

To test the strange connection thoroughly, the researchers went to the lab to try and create this effect themselves. A new set of participants was told to refrain from eating for four hours before a blind taste test. The “satiated” group of participants first ate a pound cake, faced the same binder clip survey used in the previous study. The “hungry” group worked in the reverse order – they filled out the binder clips questionnaire, stuffed as many clips as they liked into their pockets, and then ate their cake to answer cake-related questions. As it turned out, the satiated group requested fewer binder clips than the hungry group. Once again, those who were hungry wanted more stuff.

Despite taking more, the hungry people didn’t rate the clips higher than those people who weren’t hungry. This differs from food, because hunger makes food seem and taste better, even in rats. Only one component of desire was spilling over into the binder clips – the wanting.

This might sound dubious, but it turns out that psychologists have reason to believe liking and wanting use different suites of brain regions and neurotransmitters. We usually experience liking and wanting simultaneously, but this is not always true. Drug addicts or compulsive gamblers might be said to possess, especially in later stages of addiction, a powerful “GO GET IT” signal for drugs/gambling (wanting) without corresponding pleasure in its fulfillment (liking). One of the first scientists to differentiate liking and wanting, Kent Berridge, has suggested that the binder clip experiments reveal desire has a “tuning curve,” and that as we become hungry, the neurological signal to acquire food can “overshoot” into objects. The brain has evolved a mechanism that motivates us to find food when we’re hungry, but there may be some crossed wires with circuits that motivate us to think about to nonfood items.

The researchers took one last step to test if this overshoot applied in the real world. The team waylaid people exiting a department store and asked them to rate their hunger on a ten point scale while their receipts were scanned. People who bought more (nonfood) items tended to be more hungry, so hunger may really affect how we do our shopping. Does this scenario apply to online shopping, and does it affect dieters more than nondieters? The main author of the study, Alison Xu, says that more evidence is needed but, in the meantime, it might be wise to feed yourself before shopping. “If hungry consumers have to make purchase decisions, they’d better think twice before swiping their credit card.”