The Environmental Policy Stringency Index and Public Attention - Verification of the Inverted U-shaped Model

Conventional environmental governance presumes that stricter policies enhance public participation, yet Cognitive Load Theory (CLT) challenges this linear assumption based on the psychological fact that excessive policy signals exceed public cognitive capacity, triggering disengagement. This study resolves this theoretical conflict through empirical verification, by analysing Baidu search volumes for three major eco-friendly brands and changes in the Environmental Policy Stringency Index (EPSI). This paper reveals that public responsiveness to environmental policies follows a nonlinear pattern relative to EPSI intensity - a verification of the inverted U-shaped model. This finding is the first to provide empirical validation for the signal overload model in the area of policy research, advocating replacing more-is-better dogma with a more efficient policy design, especially in developing economies pursuing ambitious environmental agendas.