Mechanisms of Pro-Environmental Behavioural Spillover

If one pro-environmental behaviour (PEB) influences subsequent behaviours, this spillover effect holds significant implications for environmental policies. This paper systematically examines the psychological mechanisms underpinning PEB spillover by testing a comprehensive set of mediators within the same empirical framework. Studies were conducted in Norway ( N = 1,574) and Germany ( N = 1,938), using correlational and experimental designs. The studies did not detect any significant spillover effects. However, correlational patterns of PEB were detected, revealing consistency between prior behaviours and policy support on the one hand and intentions to engage in other PEBs and supporting other policies on the other hand. Among a comprehensive set of mediators tested, environmental concern, pro-environmental self-identity, and global warming worry were identified as significant. Experimental interventions had limited effects on the initial behaviour. We recommend longitudinal studies to better capture the dynamics of behavioural change over time and preregistration protocols to address biases in research.