How do residential open spaces influence the older adults’ emotions: A field experiment using wearable sensors

•The effects of poor, medium and high quality residential open spaces were examined.•The real-time residential outdoor characteristics and emotion data were collected.•The high-quality ROS led to a lower increase in SCL and a higher increase in vigor.•The visual-perception indices of different ROSs have differing effects on emotion.•Greenery, visual crowdedness, and enclosure had mixed effects among three ROSs. Accumulative evidence and knowledge have revealed a close relationship between environments and human emotions. Residential open space (ROS) plays a significant role in shaping the older adults’ health and well-being. However, there is a lack of evidence for the association between various types of ROSs and the older adults’ emotions. The purpose of this study is to examine and compare the effects of ROSs of different qualities on the older adults’ physiological and psychological responses relevant to emotions. Three types of ROS (poor, medium, and high quality) were selected, and data from 69 older adults were collected through a real-world field experiment using multiple wearable sensors. Residential outdoor characteristics were quantified objectively through visual-perception indices and perceived restorativeness subjectively. The emotions were analyzed based on skin conductance level, heart-rate variability, electroencephalogram, and a psychological questionnaire. The results show that compared to exposure to the poor-quality ROS, exposure to the high-quality ROS led to a significantly lower increase in SCL and a higher improvement in vigor. Significant differences in β/α indices were found across the three types of ROS. In addition, the emotional effects of the visual-perception characteristics differed according to ROS type. Blue space and safety were negatively associated with the older adults’ emotional arousal in the high-quality ROS, while safety and walkability were negatively related to the older adults’ emotional arousal in the poor-quality ROS. The effects of greenery, visual crowdedness, and enclosure on the older adults’ emotions produced mixed findings among the different types of ROS. The findings of the research can offer guidance for urban planners to improve the design of ROS to provide more emotionally pleasing and age-friendly experiences.