To avoid overeating during the holiday season, picture yourself gorging on piles of food when you arrive at the next party, says a new study.
That visualisation exercise, found a new lab-based study, could help you eat less of the foods you really want to avoid. The new finding suggests that it's OK to think about treats - as long as you think about them the right way.
"People try to avoid thinking about the foods they crave," says Carey Morewedge, an experimental psychologist at Carnegie Mellon University in Pittsburgh. "A lot of research suggests that thought-suppression is a failed strategy. This is really the nail in the coffin for that."
Plenty of studies have shown that, whether you're actually experiencing something or merely thinking about it, the same mental processes are involved.
Singing a song in your head, for example, uses the same brain structures as listening to the song would. Simply imagining a spider crawling across your shoulders can cause sweating and rapid heart thumping. And visualising an athletic feat or musical number before you play can boost your performance.
Visualisation affects eating
To see if the same might be true for eating, Morewedge and colleagues performed a series of experiments with M&Ms and cheese cubes.
First, the researchers enlisted a group of about 50 people, who thought they were taking part in an experiment on size perception. Participants were shown a picture of one M&M at a time for three seconds. Some people saw the picture three times. Others saw it 30 times. All of them were told imagine eating the chocolates when they saw them.
Next, participants were shown a series of M&Ms that varied in size and told to pick the correct one. Finally, they were offered a bowl of M&Ms - presumably for a taste test that would follow.
Secretly, the researchers later weighed the bowls to see how many chocolates each person ate.
Their results, which appear today in the journal Science, showed major difference in chocolate consumption depending on how many M&Ms people had imagined eating.
Those who had visualized swallowing 30 M&Ms ended up eating an average of between two and five chocolates at the end of the experiment - half as many as those who had imagined eating just three M&Ms. That group consumed an average of between five and nine candies.
In a series of follow-up experiments, the researchers found, people who imagined eating 30 cheese cubes ate half as much cheese compared to those who had imagined eating three cubes. That meant the finding wasn't a fluke somehow related to candy-covered chocolates.
Eating is what counts
Other experiments confirmed the finding in different ways.
Visualising M&M-eating, for example, didn't affect how much cheese people ate. Imagining that they were putting M&Ms into a bowl made no difference in how much candy people ate. Neither did imagining that they were putting three or 30 quarters into a laundry machine. And people who imagined eating more chocolate were less motivated to pile up candy-earning points in a click-heavy computer game.
Together, the experiments showed that the mental effort of imagination is not what influences appetite. Rather, it's the act of thinking specifically about eating the food you want to avoid that may help you want less of it. In both the chocolate and the cheese examples, people's level of hunger had no effect on how much they ate.
Future experiments, Moweredge added, will look at whether visualising might work against smoking and other addictive behaviors.
Paul Rozin, a psychologist at the University of Pennsylvania, says because the experiments were done in a controlled laboratory environment, it's not yet clear whether visualising a feast would work as a real-world appetite-suppressing strategy. The study also did not look at dieters, who are known to do things like give up on eating well after consuming something calorie-busting, like a milkshake.
Still, Rozin says, the findings add to a growing field of research on a phenomenon called embodied cognition, which has been revealing blurred boundaries between thinking and doing. Holding a warm cup, for example, makes people act more warmly towards others. And hearing fictional stories affects people's emotions and behaviours, even when they know the stories aren't real.
"We know that many of the same brain areas are involved in visual imaging as in actual seeing," says Rozin. "The reason this is of some significance is that we're trying to reduce food intake as a general public health measure. This suggests there are some possible mental exercises that might do that."