Empty stomachs lead to poor decisions, research says

Making important decisions on an empty stomach can lead to poor choices, according to new research.

Scientists at the University of Dundee found that hunger significantly altered 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.

The research suggests being hungry actually changes preferences for rewards entirely unrelated to food and may carry over into other kinds of decisions, such as financial or interpersonal ones.

Benjamin Vincent, who carried out the study, believes it is important that people know an empty stomach might affect their preferences and there is also a danger those in poverty may make decisions that entrench their situation.

Dr Vincent added: “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 pensions or mortgage adviser – doing so while hungry might make you care a bit more about immediate gratification at the expense of a potentially more rosy future.

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

“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.”

A group of 50 participants were tested twice for the study – once when they had eaten normally and once having not eaten anything that day.

When hungry, people expressed a stronger preference for smaller hypothetical rewards to be given immediately rather than larger ones that would arrive later.

Researchers noted that if you offer people a reward now or double that reward in the future, they were normally willing to wait for 35 days to double the reward, but when hungry this plummeted to three days.

The study is published in the latest edition of the journal Psychonomic Bulletin and Review.