A cross-modal framework for evaluating the mental health benefits of urban and natural landscapes in sustainable cities: an empirical study based on undergraduate students

Rapid urbanization has heightened the need for evidence-based healthy city planning. To resolve the methodological limitations of parallel biometric data stacking, this study developed a synchronized cross-modal framework to evaluate the restorative potential of a 9-typology urban-to-natural landscape continuum. A laboratory experiment was conducted with 42 healthy undergraduate students (21 males, 21 females; mean age = 21.4 ± 1.8 years). Brain activity (EEG), visual attention (eye-tracking), and peripheral autonomic signals (EDA, HRV, respiration) were synchronously recorded alongside the Profile of Mood States (POMS) scale. To integrate these multi-scale data streams, we formulated the Cross-Modal Restorative Index (CMRI). The empirical findings reveal a distinct, non-linear hierarchy of environmental restoration. Pristine natural environments, especially Mountainous and Field landscapes, elicited complete "Integrated Restoration," characterized by significant systemic convergence: central cognitive relaxation via posterior α power activation (Field: 7.35; Water: 7.03), robust parasympathetic upregulation (Field HF: 12518.77), and profound down-regulations in subjective tension (Mountainous: 18.6 → 12.3) and fatigue. Conversely, built landscapes demonstrated "Fragmented Restoration." Notably, Road scenes exhibited a localized dissociation where physiological calming (sharp increase in posterior α wave SD from 15.11 to 20.54) was decoupled from visual and psychological domains, with over 74% of visual dwell time remaining locked on artificial elements and subjective fatigue rising (15.3 → 16.2). These findings provide quantitative, systems-level evidence for integrating ecologically authentic blue-green infrastructure into resilient urban design.