Habit-based interventions for maintaining reduction in disposable cutlery usage: A longitudinal experiment

Adherence to long-term environmental behaviors is challenging, with unclear mechanisms for success. To address this, the presented study advances environmental behavior research by applying habit formation strategies, previously used in health interventions, to the issue of disposable cutlery usage—a major source of plastic waste. Unlike traditional incentives or nudges, it tests the effectiveness of contextual cues (e.g., reusable cutlery provision) combined with reinforcement techniques like reminders and goal-setting. Utilizing a comprehensive dataset from a three-month longitudinal experiment, comprising 20,763 panel observations and employing a marginalized two-part model, we found that both the ‘context & fixed reminder’ and ‘context & random reminder’ interventions significantly reduced disposable cutlery usage by nearly 50%. Implementing this framework across Chinese universities could potentially reduce disposable cutlery usage by 1.22 billion sets and prevent 18.2 million tons of waste per year. In comparison, the ‘context only’ was less effective, highlighting the significance of reinforcement. Notably, the ‘context & goal’ intervention proved more effective in the later stages of the experiment, suggesting that recalling goals can significantly impact behavior over time. Furthermore, we found that the effectiveness of the ‘context & fixed reminder’ intervention was significantly moderated by perceived complexity, whereas the moderation effect was insignificant for the ’context & random reminder’ intervention, emphasizing that reminder frequency should match task complexity to enhance individuals’ engagement—a critical insight previously missing from the literature. Overall, these findings enhance both theoretical understanding and practical applications in habit-based interventions for environmental behavior change and maintenance. © 2025 Published by Elsevier Ltd.