New research suggests that we might want to avoid making big decisions about the future, on an empty stomach.
We all know the perils of hunger-fueled anger, known (somewhat unfortunately) in contemporary parlance as being hangry. Hunger does funny things to people, which makes sense – it's our body's cue that we need fuel, and when that need is not satisfied, we suffer from weakness, irritability and decreased concentration.
Now researchers say there is another way in which hunger affects us: It can nudge us into making decisions that ultimately may not be in our best interest.The study, led by Dr Benjamin Vincent from Dundee University's Psychology department, found that hunger dramatically 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.”
"We found there was a large effect, people's preferences shifted dramatically from the long to short term when hungry," said Vincent. "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.”
If this sounds familiar, there was an earlier psychological study in which children were offered one marshmallow immediately or two if they were willing to wait 15 minutes. The agony! But Dundee and his team wanted to see if hunger-induced impulsiveness was similar when the reward wasn’t food.
The participants for Vincent’s study were given questions about food, but also money and other rewards, when full and then again when they had skipped a meal.
It is little surprise that people chose smaller amounts of food that were more immediate rather than waiting for a larger amount later. But they found that when hungry, the participants also opted for smaller, immediate rewards when the questions were unrelated to food, like about financial and interpersonal situations.
And the differences were dramatic: When they offered a hypothetical reward immediately or double that reward in the future, the participants were normally willing to wait for 35 days to double the reward, but when hungry this dropped to only 3 days.
"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,” Vincent said. “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 advisor - doing so while hungry might make you care a bit more about immediate gratification at the expense of a potentially more rosy future.”
Vincent believes it is important that people know that hunger might tweak their preferences in surprising ways. He also points out, importantly, that people who are hungry due to poverty may make choices that do not help their situation.
"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.