Abstract
Interventions designed to promote pro-environmental behaviour often yield inconsistent results. The Targeted Interception Theory of Behaviour Change offers a framework for improving effectiveness by aligning intervention strategies with the cognitive characteristics of behaviours, conceptualised along a continuum from habitual to scripted to considered behaviours. Across three studies, we empirically test key assumptions of this theory. Study 1 classified 18 pro-environmental behaviours based on self-reported mental processing, identifying four focal behaviours that span the continuum: purchasing energy-efficient white goods (considered), setting heating sustainably (scripted), choosing vegetarian/vegan meals at restaurants (semi-habitual), and purchasing carbon offsets with flights (highly habitual). Study 2 comprised four survey experiments comparing cognitive interventions (environmental messaging), behavioural-guidance interventions, and choice architecture changes (default change) against a control condition. While Study 1 confirmed that behaviours differ in cognitive demands, results from Study 2 were mixed: default changes increased intentions to purchase energy-efficient white goods and to choose vegetarian/vegan meals, whereas other interventions rarely outperformed the control. Study 3 reanalysed meta-analytic data from 137 field interventions, coding each by behaviour type (habitual or scripted) and intervention strategy (cognitive, behavioural-guidance, or choice architecture). These results supported theoretical predictions: choice architecture interventions were effective across both behaviour types; behavioural-guidance interventions were moderately effective for scripted behaviours but ineffective for habitual behaviours; and cognitive interventions had negligible impact. Together, these findings provide initial empirical support for Targeted Interception Theory, highlighting the importance of tailoring interventions to cognitive demands and underscoring the robustness of choice architecture as a strategy for promoting pro-environmental behaviour.