The Impact of Temporal Light Modulation on Psychological Responses Assessed by the Stroboscopic Visibility Measure

With the advent of LED lighting systems, short-term psychological responses to temporal light modulation (TLM) in offices have attracted considerable research attention in recent years. The stroboscopic visibility measure (SVM) is a leading metric for predicting the visibility of stroboscopic effects, one of visual perception effects of TLM. However, research is lacking to link TLM with potential psychological responses using the SVM metric. In this study, 10 participants joined in the experiments under 6 SVM levels (SVM: ~0.060; ~0.500; ~1.000; ~1.500; ~2.500; ~3.868) finishing tasks of subjective general rating, moving objects observation, sustained attention visual task, visual fatigue scale and PANAS (Positive and Negative Affect Scales). This study found that the SVM metric significantly evaluated the impact of TLM on psychological responses related to lighting ambiance and the moving objects observation. As expected, the stroboscopic visibility and motion dispersion scores increased with increasing SVM levels in the observation of rotating disc, and detectable stroboscopic effects were found to have negative effects on visual and work performances. However, the results of sustained attention visual task indicated that the SVM metric performed poorly in predicting the effects of TLM related to the eye saccades. High SVM levels were associated with negative experiences of lighting coziness, cognition performance and stroboscopic perception during moving objects observation. The scores were close to the expected at ~ 1.000 but exhibited a non-linearly increase with higher SVM levels. This study contributes valuable data to the ongoing discussions on setting limits for allowable modulation in practical lighting applications.