Psychological well-being benefits of urban greenness: A mixed methods approach using psycho-physiological indicators and interviews

Urban green spaces are beneficial for residents’ psychological well-being. Recent studies based on neural experiments have identified correlations between physiological responses and varying urban green environments. However, there is limited research exploring the precise quantitative relationship, leaving uncertainty about the optimal amount of greenery for positive associations on psychological well-being. Moreover, the underpinning interpretations of physiological and psychological indicators are lacking. This study recruited 94 university students in Nanjing, China to conduct a neural-based experiment and investigate the quantitative relationship between different levels of urban greenness and well-being benefits. A mixed methods approach incorporated two physiological measures (electroencephalogram (EEG) and electrodermal activity (EDA)), a self-reported questionnaire (Semantic Differential (SD) scale), and interviews exploring perceptions of street view images with varying levels of greenness. Physiological results showed that mood responses varied when exposed to different levels of greenery, findings which were also reflected in the interview data. Participants preferred urban natural areas with moderate greenery (50–55 %) and high green density spaces (65–70 %) with sufficient sunlight. Environments with better openness, fewer built elements, and straight avenues were also favored. Personal preferences and environmental familiarity influenced responses. This multimethod study demonstrates that the psychological benefits of urban greenery arise from a combination of visual greenness and broader environmental factors, calling for more holistic strategies in urban green planning and design. • Employed mixed methods integrating physiological data, self-reports, and interviews. • EEG responses showed significant relaxation responses peaking at 50–55 % and 65–70 % greenness. • Individual differences emerged as a more significant influencing factor. • Other contextual factors also exerted varying associations.