LEWIS: Lund Everyday Waste Image Set of Naturally Sourced, Normalised, and Evaluated Waste Images

Waste sorting is a cognitively demanding task with high environmental stakes. To support research on the categorisation and decision processes underlying waste sorting behaviour, this paper introduces an evaluated stimulus set of 790 images of naturally occurring waste items. The images were sampled from Danish and Swedish household waste, visually standardised, and evaluated by 526 Swedish participants on real-world frequency, how good an example they are of their waste category, and ease of categorisation. The resulting database offers a valuable resource for experiments in categorisation, judgment and decision-making, and sustainability interventions, enabling researchers to study real-world categorisation with both experimental control and ecological validity.