A new study suggests hidden odours can control our food choices
You walk through the sliding doors of the supermarket and, within seconds, your nostrils fill with the smell of freshly baked croissants and bread. Not only do you feel more at ease and happy, but your salivary glands are stimulated and your control over impulse buying slumps.
Smell has more control over our actions than we think. This includes not only strong, detectable smells but also those we cannot even consciously perceive. Can odours that go undetected manipulate our unconscious minds and in turn control our food choices? Researchers based at the Centre for Taste, Food and Nutrition Sciences in France investigated this phenomenon, focussing on healthy food options. With the ever-growing obesity and diabetes epidemic, it is becoming increasingly important to establish different ways our food preferences can be pushed towards more healthy options. So, for now, let’s put the smell of baked goods to the back of our minds.
115 participants were randomly assigned to either a control group, who were exposed to no particular odour, or the condition group, who were exposed to a ‘fruity’ odour such as pear. To ensure the strength of the odour was below the average person’s detection threshold, 10 individuals not involved in the study were exposed to the odour and, until the experimenters directed their attention to it, the individuals did not detect its presence. The study participants, unaware of the real purpose of the study, were made to wait 15 minutes in the waiting room with or without the odour before entering a real-life consumption setting such as lunch. The authors presented the 115 participants with 2 different menu options for each starter, main and dessert course. One starter and one main course option contained fruit and vegetables and one dessert option included fruit whilst the other options included none. The authors predicted that exposure to a pear odour whilst in the waiting room would push the participants’ preference towards the ‘fruity’ dessert, as pear is usually consumed within dessert dishes rather than starters or mains.
Compared to the control group, the condition group showed a significantly higher preference for the apple compote than the brownie for dessert. Moreover, their preferences for the starter and main course options containing fruit and vegetables was unaffected which supports the theory that the pear odour affects the preference of a dish in which it is normally consumed ie. dessert.
There are of course limitations to this study. How can we be sure that the detection threshold for the pear odour is similar between participants? The authors claim all participants reported no problems in odour perception and were also between 18-52 years old thus excluding the older age range within which olfactory sensitivity usually declines. It would also be of interest to explore the effect of exposing individuals to the fruity odour during the menu task as this would be more similar to a restaurant or grocery shopping setting.
Despite these limitations, this study provides insight into the wonders of unconscious processing of stimuli such as odours and how these can be manipulated to promote healthy eating behaviours. The junk food industry already exploits our visual and odour senses but if we are to beat them at their own game we need to counteract these methods.
So, it’s time to wake up and smell the coff- I mean, fruit!
Gaillet-Torrent, M., Sulmont-Rossé, C., Issanchou, S., Chabanet, C., & Chambaron, S. (2014). Impact of a non-attentively perceived odour on subsequent food choices Appetite, 76, 17-22 DOI: 10.1016/j.appet.2014.01.009