The inexplicable anger that overtakes us when we need to eat can sneak up on us and is markedly different from regular hunger symptoms. The bad mood known as "hanger" can leave loved ones baffled.
Until recently, not a lot was known about the phenomenon that turns normal hunger pangs into a turbulent emotional state, even though it's widely acknowledged that hunger can trigger aggressive behaviour.
A study published in in the journal Emotion, suggests that heightened stress levels and being unaware of one's current emotional state can mean a person crosses the threshold from hungry into hangry.
Lead author Jennifer MacCormack, told TIME that to gain insight into what makes a person hangry, her team conducted experiments to identify the factors that might cause it.
A total of 400 people completed online experiments to help get to the bottom of the issue. In the first, they were shown either a positive, neutral or negative image (like a kitten, a plate and a spider). They were then shown a Chinese pictograph - an image intended to be ambiguous in feeling - and asked to rate the image along a scale of positive to negative. Data was also collected about their hunger levels at the time of viewing the image.
If they had been shown a negative image before the pictograph, they were more likely to rate it as an unpleasant image, indicating that being in a state of increased negativity affected whether they became hangry.
TIME also cites another study of 200 students who were instructed to attend the experiment either having eaten or having fasted. Some then wrote about their current emotions, while other wrote about a neutral topic. All were then exposed to a negative situation, in which the computer they were working on crashed right before they finished a lengthy set task.
In addition, a staff member would enter the room and blame the student for the occurrence. Following this the students were surveyed about the experiment and their emotions.
TIME reports that, "The students who hadn't eaten were more likely to report feeling stressed and hateful if they had not done the writing exercise focusing on their emotions. They were also more likely to describe the researcher as harsh and judgmental."
The group who had written about their emotional state beforehand were much less likely to give negative feedback even if they had fasted, leading researchers to believe that being in tune with one's own emotions plays a role.
Study co-author Kristen Lindquist said, "People in our studies were more likely to feel intense negativity in general when they were hungry and something bad happened—suggesting that feeling hungry can turn up the dial on lots of negative emotions such as anger, stress or disgust."
MacCormack adds, "By better understanding the factors that lead us to become hangry, we can give people the tools to recognise when hunger is impacting their feelings and behaviours."