Psychological strategies to promote household recycling. A systematic review with meta-analysis of validated field interventions

Recycling urban waste is a priority to preserve natural resources and reduce pollution. However, the entire recycling process is not possible without the cooperation of citizens through primary separation of waste at home. Various psychological intervention strategies have been applied to promote household recycling, such as information, feedback, incentives, commitment, behavior modeling and environmental alterations. The purpose of this article is to systematically review and evaluate through a meta-analysis their effectiveness, investigating also existing connections between intervention-based research and research on recycling determinants. A random-effect meta-analysis with a sample of 36 studies reporting 70 interventions revealed that social modeling and environmental alterations were the most effective techniques. The examination of underlying factors considered in the interventions also showed that some of them are rarely accounted for when designing the interventions. The findings are discussed along with possible future directions for interventions aiming at promoting recycling.