Engaging the public in sustainable actions is essential for reaching local and global sustainability goals. The first two research questions of this dissertation focus on strategies to reduce contamination of waste in private and public areas through active and passive prompts, and immediate feedback on errors. The third research question expands the behavioural analysis to examine willingness to act in several pro-environmental domains: waste, water, food and biodiversity. Together, this thesis aims to contribute to best practices in the field of waste diversion, community engagement and long-term pro-environmental behaviour change.

The first study of this dissertation shows that providing active guidance during a public festival helped people sort waste significantly better than stand-alone prompt interventions of 2D signage and real-life 3D items. The effects were consistent across all waste streams and show the importance of guidance and feedback at the time of sorting to help reduce contamination and achieve zero waste goals. The second study demonstrated that immediate feedback on sorting errors through a computer game also improved sorting accuracy in the lab, and benefits persisted even when feedback was removed in the second trial. The game was additionally tested in a field study in student residence buildings, resulting in the weight of compost materials increasing while bin contamination decreased. The third key finding of this dissertation demonstrates that botanical gardens can help engage local visitors in sustainability topics through team-building activities while immersed in nature. After their visit, participants were more knowledgeable about environmental issues, more connected to nature, and showed greater willingness to engage in sustainability actions.