Effects of Spatial Type and Scale of Small Urban Open Spaces on Perceived Restoration: An Online Survey-Based Experiment

Small urban open spaces are critical components of high-density urban environments, and could bring multiple health benefits. However, the factors related to the restorative effect of these small urban open spaces are not well studied. This study explored how site type (lawn, water, and plaza) and spatial scales (10 × 10 m, 20 × 20 m, 30 × 30 m, and 40 × 40 m) might be associated with small urban open space’s restorative effects. We created the virtual scene images of the 12 sites and used PRS-11 to measure 1130 participants’ perceived restoration when viewing those images. The results indicated that lawn has the highest restorative effects, and are the most preferred. No significant differences in the restorative effects of sites with different spatial scales were detected, even a 10 × 10 m site has considerable restorative effects. We found high preference contributes to larger differences in the restorative effects of lawns and plazas. Those who prefer the sites may gain more restoration increases when viewing lawn scenes compared to plaza scenes. Moreover, adults over 50 years old have higher perceived restorations, and young adults aged 18–25 have a greater increase in restoration between plaza scenes and natural scenes, indicating young adults could benefit more from the building of small green spaces. These findings have direct implications for design practice. More small urban open spaces of lawn and water should be built to provide more restoration benefits, especially for young people.