Coupling micro-behaviours with macro-systems: A Double Black Box modulation model for sustainable design

Uncertainty in user behaviour remains a bottleneck for sustainable design. This study presents a User-System Double Black Box Model, grounded in cybernetics, to organize relationships among design inputs, behavioural outputs and system-level feedback. Using an explanatory sequential mixed-methods design, it integrates system logs, questionnaires and interviews across three exploratory prototypes in China: packaging recycling, waste sorting and furniture upcycling. The findings suggest that functional, informational and emotional inputs, when configured together, are associated with improved or more stable behavioural outcomes. Feedback temporality may also be relevant: immediate feedback is associated with high-frequency routines, whereas slower narrative feedback may be relevant to low-frequency, emotionally involved practices. In the Chinese community case, face-related concerns may function as a visibility-sensitive feedback factor. Rather than proposing a universal theory, the model provides a middle-range operational framework and input modulation matrix for organizing sustainable behaviour interventions within specific socio-technical systems.