Understanding Barriers to Public Recycling Behaviour in Hamburg: A Mixed-Methods Study of Human–Technology Interaction and User-Centred Design

Abstract

This study investigates why individuals disengage from appropriate recycling behaviour at public collection points and examines the interaction-design and behavioural factors underlying this gap. The study employed a Sequential Mixed Methods approach between March and June 2026. Research began with sensory observations of existing recycling environments, followed by semi-structured interviews with residents and stakeholders (Stadtreinigung Hamburg and Starship Technologies), a community focus group, behavioural data collection, and an online survey. A total of 83 survey responses were collected, of which 55 were included in the final analysis. The combination of qualitative and quantitative methods enabled cross-validation of findings and provided a broader understanding of users' needs, expectations, and experiences. Findings triangulated across methods indicate that incorrect disposal is driven less by the willingness to recycle than by difficulties in decision-making at the point of disposal. Most participants generally expressed interest in recycling and a willingness to contribute, but their ability to act on this intention was affected by cognitive load, poor environmental visibility, low trust in system outcomes, and a mismatch between institutional system logic and users' everyday mental models. The study also identifies openness toward robot-assisted waste collection, tempered by concerns regarding data privacy, reliability, and cost. 

These findings inform a set of evidence-based design requirements for human-centered recycling interventions in dense urban environments and provide the empirical foundation for the design developed from these findings, which is beyond the scope of the present study.