Making decisions on an empty stomach is a terrible idea

Many of us know the feeling of being “hangry”, which can lead us to lose our tempers if we’re hungry and angry simultaneously. Making a major life decision while in such a state can have even more drastic consequences.

A new study, conducted by Dr Benjamin Vincent from the University of Dundee in the UK, has found that hunger significantly alters people’s decision-making, making them impatient and more likely to settle for a small reward that arrives sooner than a larger one promised at a later date.

Survey participants were asked questions about food, money and other rewards when satiated and again when they had skipped a meal, and it was found that hungry people were more likely to settle for smaller food incentives that arrived sooner, but more significantly, being hungry actually changes preferences for rewards entirely unrelated to food.

This indicates, Dr Vincent surmised, that a reluctance to defer gratification may carry over into other kinds of decisions, such as financial and interpersonal ones.

It is important, he said, “that people know that hunger might affect their preferences in ways they don’t necessarily predict. There is also a danger that people experiencing hunger due to poverty may make decisions that entrench their situation”.

“We found there was a large effect – people’s preferences shifted dramatically from the long to short term when hungry,” he said.

“This is an aspect of human behaviour which could potentially be exploited by marketers, so people need to know their preferences may change when hungry. People generally know that when they are hungry, they shouldn't really go food shopping because they are more likely to make choices that are either unhealthy or indulgent.”

“Our research suggests this could have an impact on other kinds of decisions as well. Say you were going to speak with a pension or mortgage adviser – doing so while hungry might make you care a bit more about immediate gratification at the expense of a potentially rosier future.

“This work fits into a larger effort in psychology and behavioural economics to map the factors that influence our decision-making,” Dr Vincent continued.

“This potentially empowers people as they may foresee and mitigate the effects of hunger, for example, that might bias their decision-making away from their long-term goals.”

Dr Vincent and his co-author and former student Jordan Skrynka tested 50 participants twice – once when they had eaten normally and once having not eaten anything that day.

“We wanted to know whether being in a state of hunger had a specific effect on how you make decisions only relating to food or if it had broader effects, and this research suggests decision-making gets more present-focused when people are hungry,” said Dr Vincent.

“You would predict that hunger would impact people’s preferences relating to food, but it is not yet clear why people get more present-focused for completely unrelated rewards. We hear of children going to school without having had breakfast, many people are on calorie restriction diets, and lots of people fast for religious reasons.”

“Hunger is so common that it is important to understand the non-obvious ways in which our preferences and decisions may be affected by it.”

The research is published in the latest edition of the journal Psychonomic Bulletin & Review.