Summary: Hunger significantly alters a person’s decision-making ability, making them more impatient and more likely to settle for a small reward now than wait for a bigger reward in the future.
Source: University of Dundee
We all know that food shopping when hungry is a bad idea but new research from the University of Dundee suggests that people might want to avoid making any important decisions about the future on an empty stomach.
The study, carried out by Dr Benjamin Vincent from the University’s Psychology department, 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.
Participants in an experiment designed by Dr Vincent were asked questions relating to food, money and other rewards when satiated and again when they had skipped a meal.
While it was perhaps unsurprising that hungry people were more likely to settle for smaller food incentives that arrived sooner, the researchers found that being hungry actually changes preferences for rewards entirely unrelated to food.
This indicates that a reluctance to defer gratification may carry over into other kinds of decisions, such as financial and interpersonal ones. Dr Vincent believes it is important 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 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.
“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 forsee 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.
For three different types of rewards, when hungry, people expressed a stronger preference for smaller hypothetical rewards to be given immediately rather than larger ones that would arrive later.
The 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 only 3 days.
The work builds on a well-known psychological study where children were offered one marshmallow immediately or two if they were willing to wait 15 minutes.
Those children who accepted the initial offering were classed as more impulsive than those who could delay gratification and wait for the larger reward. In the context of the Dundee study, this indicates that hunger makes people more impulsive even when the decisions they are asked to make will do nothing to relieve their hunger.
“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.”
University of Dundee
Dominic Glasgow – University of Dundee
The image is in the public domain.
Original Research: Open access
“Hunger increases delay discounting of food and non-food rewards”. Jordan Skrynka, Benjamin T. Vincent.
Psychonomic Bulletin & Review doi:doi:10.3758/s13423-019-01655-0.
Hunger increases delay discounting of food and non-food rewards
How do our valuation systems change to homeostatically correct undesirable psychological or physiological states, such as those caused by hunger? There is evidence that hunger increases discounting for food rewards, biasing choices towards smaller but sooner food reward over larger but later reward. However, it is not understood how hunger modulates delay discounting for non-food items. We outline and quantitatively evaluate six possible models of how our valuation systems modulate discounting of various commodities in the face of the undesirable state of being hungry. With a repeated-measures design, an experimental hunger manipulation, and quantitative modeling, we find strong evidence that hunger causes large increases in delay discounting for food, with an approximately 25% spillover effect to non-food commodities. The results provide evidence that in the face of hunger, our valuation systems increase discounting for commodities, which cannot achieve a desired state change as well as for those commodities that can. Given that strong delay discounting can cause negative outcomes in many non-food (consumer, investment, medical, or inter-personal) domains, the present findings suggest caution may be necessary when making decisions involving non-food outcomes while hungry.