Looking at visual cues associated with overweight or obese people can influence a person’s sense of smell, according to a new study. The more a person is turned off by an obese image, the worse he or she will tend to rate a particular scent.
The findings suggest that the extent of negative bias toward overweight and obese people may be greater than previously thought. Surprisingly, people with higher BMIs tended to be more critical of other heavier people, as higher-BMI participants gave scents a lower rating when scent samples were matched with an obese or overweight individual.
“You wouldn’t think that not liking someone’s weight could then be seen in a totally different sensory modality, which makes us think, ‘How else is weight stigma affecting our lives that we don’t even know about?'” said Dr. A. Janet Tomiyama, an assistant professor of psychology at the University of California, Los Angeles (UCLA).
Tomiyama conducted the research with Angela Incollingo-Rodriguez, a UCLA doctoral student in psychology, and Dr. Andrew Ward, a professor of psychology at Swarthmore College.
“This is the first step in proving that the consequences of weight stigma could be very widespread in ways that we don’t even know,” Tomiyama said.
Lead author Incollingo-Rodriguez added that while some people are overtly biased, others are more subtle about it and may not even be aware that they harbor negative feelings toward heavy people.
“There are no checks and balances on weight stigma in the way you would see with racism, sexism, or homophobia,” Tomiyama said.
In two related studies, participants were shown one of two sets of images. Both sets contained photographs of different people — half who were visibly overweight or obese, and half who were normal weight or thin — along with a series of “distractor” objects.
Along with each image, subjects were asked to smell a container of lotion tinted with a different food coloring. Although all of the scent samples were actually fragrance free, the researchers wanted to see whether participants would perceive them to have different smells, and whether their reactions could be associated with the pictures they were viewing at the same time.
With each visual image, a researcher placed the scent sample under the participant’s nose. Participants were asked to rate each scent on a scale from one to 11.
The researchers found that when overweight or obese people were on the screen, participants gave worse ratings to the scent samples, while photos of average-sized or thin people tended to trigger higher ratings.
The link between visual stimuli and sense of smell is well-established: Prior research has connected the perception of negative odors to feelings of disgust.
“Right now, we only have a couple of ways to measure implicit attitudes, such as an implicit-association test measure,” Incollingo-Rodriguez said. “We wanted to see if looking at something you find unappealing or unpleasant could influence how you evaluate a smell that has nothing to do with weight.
“This shows that something is happening implicitly, and we may have tapped into a new methodology for assessing people.”
She said weight bias can affect people’s everyday lives in many different ways, including how they are treated in social situations, the quality of medical care they receive, and hiring and promotion decisions.
“It also undermines people’s motivation to diet and exercise,” Incollingo Rodriguez said. “If anything, stigma is a barrier to these lifestyle changes that people commonly use to lose weight.”
The findings are published by the International Journal of Obesity.