Effects of digital Just-In-Time nudges on healthy food choice – A field experiment

Novel digital applications enable intervening in health behavior at moments hitherto impossible. Handheld self-scanning solutions in supermarkets allow providing nudges immediately in response to the product choice. While a nudge presented at this moment, in the optimal state of vulnerability/opportunity and receptivity, may serve as a cue to action and trigger healthier choices, post-choice biases instead predict that changing decisions is challenging. We investigated whether visibility nudges (product suggestions) and descriptive and evaluative nutritional labeling nudges provided immediately in response to choice can stimulate healthier food choices. Experimental manipulations were integrated in the self-scanning function of a smartphone application that allowed scanning and purchasing products in the physical supermarket. We compared: 1) a control version without adaptations, 2) a visibility nudge version in which after scanning an unhealthy product a pop-up with a healthier alternative appeared, 3) a version similar to version 2 but with additionally a descriptive nutritional label nudge denoting the healthiness of the alternative, and 4) a version similar to version 2 but with additionally an evaluative nutritional label nudge denoting the healthiness of the alternative. Sales data were collected during a 5-week period. The percentage of healthier products purchased was significantly higher for the visibility nudge version in which the healthier alternative was suggested without any additional nudge (37.7% healthier) compared to the control condition (29.9%), and the versions with an additional descriptive (30.0%) or evaluative nutritional label nudge (28.2%). The findings imply that saliently suggesting a healthier alternative stimulates healthier purchasing behavior but that an additional nudge emphasizing health may cancel this effect out.