Nudging to inform: Priming and social norms to facilitate waste composting

The combination of social norms and nudges has proven to be a powerful tool for inciting people to adopt pro-environmental behaviors. In this study, we implemented nudges that promote pro-environmental behavior still not explored by behavioral economics: waste composting. In particular, we designed priming and social norm nudges to incite people looking for information about waste composting possibilities. We set up a field experiment with a two-fold purpose. First, remove the barriers towards collective composting in Lyon by using posters related to priming theory with QR Codes that redirect directly to the website of a local association dedicated to environmental actions. Second, these posters created new social norm mechanisms. Since composting is still practiced by only a minority of people in France, the standard way of combining nudges and social norms is insufficient in this context. Here, we focus on descriptive and injunctive norms with local dimensions. These new norms aimed to make the nudge more efficient by increasing the number of scans. We observed that the scans of the posters allowed for a significant increase in the visits to the website over several months, thus improving information about collective waste composting. Although no significant differences were found between social norms treatments, these results show that the QR Code is a promising tool for implementing nudges.