Developing and testing a protocol to systematically assess social interaction with urban outdoor environment.

Social interaction is significant for individuals' mental and psychological well-being in communities. With the growing demand for outdoor activities in urban settings under the COVID‑19 pandemic, urban parks have become important public resources for human social activities. Researchers have developed numerous instruments to measure park use behaviors, but most are designed for assessing physical activity while ignoring social interactive behaviors. Despite the importance, no single protocol objectively assesses the range of social interactions in urban outdoor environments. To bridge the research gap, we have developed a social interaction scale (SIS) based on Parten's scheme. The innovative protocol, named Systematically Observing Social Interaction in Parks (SOSIP) was developed based on the SIS, allowing systematic evaluation of human's interactive behaviors in outdoor environment both from their levels of social interaction and group size. The psychometric properties of SOSIP were established through the verification of content validity and reliability tests. Additionally, we applied SOSIP to explore relationships between park features and social interaction via hierarchical linear models (HLMs). Statistical comparisons between SOSIP and other forms of social interaction were discussed and indicated strong reliability of applying SOSIP. The results indicated SOSIP is a valid and reliable protocol for objectively assessing social interactive behaviors within urban outdoor environments and informing better understanding of individuals' mental and psychological health benefits.