Natural or balanced? The physiological and psychological benefits of window views with different proportions of sky, green space, and buildings

Window views are an important landscape that affect human health in the urban built environment, but the impacts and health-benefit differences of window view elements have not been studied in depth. Previously, window views have been categorized as only natural or unnatural; in contrast, we propose a more differentiated classification involving three elements (sky, buildings, and green space). A total of 160 subjects were recruited and divided into 8 groups; these groups were shown window views (7 groups with different element ratio combinations and 1 control group), and the effects on 27 physiological and psychological indicators were assessed. This is the first study to provide evidence of the benefits of window views for restoring attention, reducing negative emotions, and lowering stress according to multiple indicators. More importantly, we conducted a comprehensive comparison of the benefits of window views composed of different element ratios using ternary phase diagrams and matrix diagrams. Overall, window views with a higher percentage of sky elements or green space elements, as well as window views with a balance of the three elements, had a better comprehensive effect. The results of this study can inform urban landscape planning and architectural design to improve human health.