Natural dynamics without nature? Effects of motion type in light patterns on stress recovery

While nature’s restorative effects on humans are well established, the role of its temporal dynamics remains underexplored. This study investigates whether the type of motion (natural vs. non-natural) influences stress recovery, using projected light patterns on a wall as a medium. We introduce an image-processing approach that extracts motion from a real dappled light video and applies this natural motion to abstract shapes, thereby controlling for confounding spatial characteristics. In a between-subjects laboratory experiment (N=67), participants experienced one of three experimental conditions during recovery following a stressor task: a static pattern (control, n=21), a dynamic pattern with natural motion (n=22), and a dynamic pattern with non-natural motion (n=24). Stress was assessed by physiological measures of skin conductance level (SCL), heart rate variability (HRV), and heart rate (HR), as well as subjective arousal. Natural motion led to significantly greater recovery (after outlier removal) than the non-natural one, as indicated by HRV. No differences were found on SCL, HR, or subjective arousal. Unexpectedly, the natural motion condition was not appraised as more natural than the non-natural one. Both dynamic conditions were perceived as more stressful and distracting than the static control, and only the non-natural condition was further rated as less relaxing and less pleasant, underscoring its more negative appraisal. While HRV results provided limited evidence that natural temporal dynamics may support physiological stress recovery compared to non-natural ones, neither dynamic condition differed significantly from the static control condition, and further research is needed to confirm whether this effect reflects a genuine restorative benefit of natural motion or an adverse impact of non-natural motion. • Using image processing, natural motion was isolated from a real dappled light. • Natural motion enhanced stress recovery (based on HRV) compared to non-natural motion. • Both dynamic light conditions were appraised less positively than the static one. • Natural dynamics aided recovery without conscious recognition of naturalness. • Effects may reflect harm from non-natural motion rather than the benefit of natural motion.