Nudging healthier snack choices: a consumer neuroscience study on visual and olfactory interventions in university vending machines

As students begin university, they often experience weight gain, making interventions in the academic environment crucial. Nudging, a subtle way to guide behavior shows promise in promoting healthier food choices; despite its success in school cafeterias, its application to vending machines remains limited. Our study aims to test the effectiveness of visual and olfactory nudges, alone and in combination, on university students' vending machine snack choices. Consumer neuroscience (Electroencephalography -EEG, skin conductance, and Eyetracking) tools were employed to understand the cognitive and emotional effects of these nudges. 88 university students were exposed to different nudging conditions as they observed and selected snacks from a vending machine replica. Results showed that both visual and olfactory nudges significantly increased the selection of healthier snacks, while the combined condition did not. Skin conductance data suggested that the nudges may induce relaxation, which may promote healthier choices, while the EEG Approach-withdrawal Index (AWI) confirmed a lower cognitive orientation toward the snacks in the combined version. Eyetracking data showed that healthy snacks' lower shelf positioning distracted attention from them; interestingly, the combined condition also delayed attention toward healthier products, suggesting this nudge condition's ineffectiveness. In conclusion, our study highlights the effectiveness of visual and olfactory nudges alone in promoting healthier vending machine snack choices among college students. However, combining sensory stimuli may reduce their effectiveness, suggesting the importance of using single sensory nudges. In addition, displaying healthier snacks at eye level may increase their visibility and attract students' attention, further promoting healthier choices. These findings have practical implications for designing interventions in academic settings to prevent weight gain and promote healthier eating behaviors among college students.