Effects of Personalized Lighting on Subjective Ratings, Cognitive Performance, and Physiological Stress Response in a Simulated Office Environment

Abstract

LEDs simplify the personalization of lighting. However, research on the effects of personalizable lighting is in its infancy. The present study investigates the impact of personalizable workplace lighting on subjective parameters, cognition, and physiological stress while performing cognitive tests. In a cross-over design, 22 participants were randomly assigned to standard workplace lighting and lighting with adjustable illuminance and color temperature for two hours on two separate days. Subjective outcome measures were sleepiness, affect, and asthenopic complaints. We further assessed vigilance and three cognitive domains (task switching, working memory, and information processing) and derived heart rate variability parameters from an electrocardiogram. Some beneficial effects of personalizable lighting on cognitive performance were observed, although the overall results remain inconclusive. Standard and personalizable lighting did not differ in subjective ratings and physiological stress responses. Exploratory analysis of personalizable lighting revealed significant variation in self-selected workplace illuminances and limited variation in self-selected correlated color temperatures. Despite the preference for increased workplace illuminance under personalizable lighting, no visual impairment was observed compared to standard lighting. Personalizable workplace lighting is a promising new design feature to support individual visual and nonvisual lighting needs in daylight-deprived environments.