We all know how unpleasant being hungry is, but some people are much worse than others — they go full-on “hangry.” But what does this combination of hungry and angry really mean? Researchers have found that it’s much more than just a drop in the blood sugar — it’s a complex result which involves an interplay of biology, personality, and environmental cues.

Few things are worse than a persistent hunger. If you’re privileged enough to live in this day and age, in the developed world, access to food is likely not a serious concern for you. So feeling hungry should be nothing more than a fleeting feeling, with little impact on our day to day lives. But that’s not really the case.

Some people become very irritable when they’re hungry, a phenomenon colloquially called “hanger.”

“We all know that hunger can sometimes affect our emotions and perceptions of the world around us, but it’s only recently that the expression hangry, meaning bad-tempered or irritable because of hunger, was accepted by the Oxford Dictionary,” said lead author Jennifer MacCormack, MA, a doctoral student in the department of psychology and neurocience at the University of North Carolina at Chapel Hill. “The purpose of our research is to better understand the psychological mechanisms of hunger-induced emotional states — in this case, how someone becomes hangry.”

While being hangry starts with being hungry, that’s not all there is to it. After all, most of us are able to navigate life pretty well even when we’re hungry.

“You don’t just become hungry and start lashing out at the universe,” said assistant professor Kristen Lindquist, PhD, the study’s co-author. “We’ve all felt hungry, recognized the unpleasantness as hunger, had a sandwich and felt better. We find that feeling hangry happens when you feel unpleasantness due to hunger but interpret those feelings as strong emotions about other people or the situation you’re in.”

In the new experiments, scientists had over 400 participants look at a photo and rate how pleasant it was on a scale of 1 to 7. Some of them were shown an image designed to induce positive feelings, others were shown a negative image, while others were shown a neutral image, such as a Chinese pictograph. Participants were also asked to rate how hungry they are.

Researchers found that when participants were primed with a negative image, they were more likely to rate ambiguous Chinese pictographs as negative. There was no effect for neutral or positive images. So in other words, when something negative happens first, people are more likely to rate something neutral as negative, particularly if they are hungry. This suggests that environmental cues are a key to becoming hangry.

“The idea here is that the negative images provided a context for people to interpret their hunger feelings as meaning the pictographs were unpleasant,” said MacCormack. “So there seems to be something special about unpleasant situations that makes people draw on their hunger feelings more than, say, in pleasant or neutral situations.”

An in-depth interview with MacCormack, detailing her findings.

But that doesn’t tell the whole story. In a lab experiment involving 200 university students, researchers asked participants to either eat or fast beforehand. For the experiment, they were asked to participate in a scenario designed to evoke negative emotions. Students were asked to complete a tedious exercise on a computer that, unbeknownst to them, was programmed to crash just before it could be completed. After it would crash, a researcher would come into the room and blame the student for the crash.

Participants were then asked to fill out a questionnaire on their emotion and the quality of the experiment. Hungry individuals were more likely to report negatively about the event, and they were also more likely to believe that the researcher was more judgemental or harsh.

“A well-known commercial once said, ‘You’re not you when you’re hungry,’ but our data hint that by simply taking a step back from the present situation and recognizing how you’re feeling, you can still be you even when hungry,” MacCormack said.

So the bottom line is that this is a complex mind-body effect, MacCormack concludes. She believes the “hangry” effect also caries out to other physical trying experiences, such as fatigue or inflammation, but this hasn’t been confirmed yet.

“Our bodies play a powerful role in shaping our moment-to-moment experiences, perceptions and behaviors–whether we are hungry versus full, tired versus rested or sick versus healthy,” she said. “This means that it’s important to take care of our bodies, to pay attention to those bodily signals and not discount them, because they matter not just for our long term mental health, but also for the day-to-day quality of our psychological experiences, social relationships and work performance.”

The study “Feeling Hangry? When Hunger Is Conceptualized as Emotion” has been published in the journal Emotion.