"Health Is in the Air": Visual and Olfactory Nudges and Food Choices at University Vending Machines.

Background/

Objectives

Ambient sensory cues can influence food choice, yet their role in everyday environments remains underexplored, with much of the existing evidence derived from laboratory studies. This is particularly relevant in university settings, where students often make rapid, convenience-driven choices that may be nudged toward healthier options by sensory cues (e.g., images or scents).

Methods

A quasi-experimental field study was conducted across three consecutive one-week conditions: control, visual (a nature-themed poster), and olfactory (jasmine fragrance). Snacks were classified according to perceived healthiness ratings from a pre-study questionnaire. After predefined exclusions, purchases were analyzed using binary logistic regression, with condition as the main predictor and price and time of day examined as additional factors.

Results

Among N = 1043 purchases, products classified as healthy were more frequent during the olfactory week than during the control and visual weeks. The visual condition did not differ significantly from control. Higher prices were associated with lower odds of purchasing a product classified as healthy, whereas time of day was not significantly associated with purchasing behavior.

Conclusions

These findings provide field-based evidence suggesting that olfactory cues may be associated with a shift toward food choices perceived as healthier in vending-machine environments, pointing to their potential as a low-cost sensory nudging strategy while highlighting the need for confirmation through randomized or counterbalanced designs and replication across diverse real-world food-choice settings beyond university contexts.