Abstract

This thesis investigates the cognitive mechanisms that impede environmentally responsible behaviour, focussing specifically on the Negative Footprint Illusion (NFI) - a systematic judgement error in which the addition of environmentally friendly items to conventional ones paradoxically reduces perceived environmental impact. Across five experiments, this research examined the robustness and boundary conditions of the NFI in the context of recycling. Experiment 1 demonstrated that item type (e.g., bottles vs. houses) did not moderate the illusion, while Experiment 2 showed that the effect persists across both same-category and cross-category pairings. Experiments 3 and 4 tested individual differences, revealing that neither working memory capacity nor actively open-minded thinking predicted the magnitude of the illusion. Experiment 5 explored temporal framing and the potential for corrective nudges, finding that judgments were guided by averaging rather than summation, even when participants were prompted to consider total impact. Taken together, the findings suggest that the NFI arises from an averaging bias applied during intuitive vice–virtue categorisation, rather than from limitations in cognitive capacity or domain knowledge. This work contributes to our understanding of how cognitive biases distort environmental judgment and has important implications for the design of interventions aimed at promoting sustainable behaviour.