Testing the effects of health-benefit, environmental-benefit and co-benefit priming for promoting sustainable food choice and their psychological mechanisms: A randomized controlled trial combined with eye tracking

Promoting sustainable diets is consistently documented to be beneficial to health, the environment, and long-term food security. There remains limited understanding of the effects of activating the goal of sustainable diets for achieving co-benefits on sustainable food choices and the potential mechanisms. This study was a pre-registered online randomized controlled trial combined with eye tracking to compare the effects of three priming interventions: health-benefit priming (HP), environment-benefit priming (EP), and combined-benefit priming (CoP), on sustainable food choice. Sustainable food choices were assessed by a simulated online shopping task. Participants' eye movement data were tracked while they were choosing foods during simulated online shopping. Participants' executive function (EF), environmental values, health values, and social orientation values were also measured. The results showed a significant difference in sustainable food choices among the four groups, with CoP showing a significant increase compared to the control. The eye-tracking data revealed that the attention to sustainable foods with an eco-friendly logo mediated the association between priming and participants’ sustainable food choices. Furthermore, priming with the co-benefits of sustainable diets can be more effective for participants with greater delay discounting to increase their sustainable food choices. These findings suggest that priming with co-benefits of sustainable diets can be a promising strategy to support more sustainable food choices particularly for consumers with more difficulty in delaying their immediate awards.