Materiality and Mind: The Psychological Effects of Natural vs Synthetic Building Materials in Interior Spaces

This study examines the psychological effects of natural versus synthetic building materials in interior environments, with a particular focus on emotional regulation, stress response, and perceived spatial comfort. As contemporary interior design increasingly incorporates engineered polymers, composite panels, and artificial surface finishes, questions have emerged regarding how material composition influences human cognitive and affective responses. Drawing upon theories of biophilic design, environmental psychology, and neuroarchitecture, this research investigates whether natural materials such as wood and stone elicit measurably different psychological and physiological reactions compared to synthetic materials including PVC, epoxy, and laminated composites.An experimental mixed-method design was employed. Participants were exposed to controlled interior simulations featuring identical spatial configurations differentiated only by material composition. Psychological responses were assessed using validated affective scales, while physiological indicators including heart rate variability and salivary cortisol were recorded to measure stress activation. The results indicate that interiors dominated by natural materials significantly reduced reported stress levels, increased perceived warmth and safety, and improved attentional stability. In contrast, synthetic-dominated environments were associated with higher arousal levels and reduced emotional comfort, particularly in prolonged exposure scenarios.The findings suggest that material selection in interior architecture extends beyond aesthetic and functional considerations, exerting measurable influence on human well-being. By integrating material science with environmental psychology, this study contributes empirical evidence to support biologically informed design strategies in contemporary architectural practice.