Ronft Steffen

• Light is an essential aspect of daily life, exerting a profound influence on various physiological and behavioral processes, including circadian rhythms, alertness, cognition, mood, and behavior. Technological advances, particularly the widespread adoption of light-emitting diodes (LEDs), have significantly accelerated the impact of lighting on the human experience. With the increasing global accessibility to electric and modern lighting systems, there is a pressing need to scientifically investigate the human-centered effects of lighting for the billions of people worldwide who encounter natural and electric lighting in their daily lives. Extensive interdisciplinary research across fields such as physics, engineering, psychology, medicine, business administration, and architecture has explored the biological and psychological effects of lighting, underscoring the immense potential for further advancements in this domain. Notably, innovative lighting technologies and strategies hold tremendous promise in enhancing human health, performance, and overall well-being. Beyond physical spaces, three-dimensional virtual environments, including metaverse platforms, are becoming increasingly important. Simulated lighting in virtual spaces can have visual and non-visual effects on users. As technological progress and digitalization extend globally, more individuals will be exposed to virtual lighting scenarios. Consequently, exploring the human-centered lighting effects in virtual environments offers a compelling opportunity to improve the quality of user experiences. This thesis demonstrates the adaptability of established measurement methods from physical illumination and perception research for virtual environments. This thesis comprises three parts. The first part reviews the current state of research on lighting and its influences on humans, examines research methods in lighting research, and identifies research gaps. The second part investigates the effects of lighting on complex emotional and behavioral constructs, specifically conflict handling. Elaborate laboratory experiments explore lighting as an independent variable, including realistic correlated color temperature (CCT) levels and enhanced CCT changes. Statistical analyses provide in-depth examination and critical discussion of the effects. The third part explores lighting in virtual spaces, considering literature, methodological approaches, and challenges. Two studies investigate visual and non-visual effects, and preferences in virtual environment design. Comparative analysis of the data yields implications for research and practice, including the interdisciplinary perspective of a novel approach called human-centric virtual lighting (HCVL). In conclusion, this thesis comprehensively explores the impact of lighting on the human experience in both physical spaces and virtual environments. By addressing research gaps and employing contemporary methodologies, the findings contribute to our understanding of the effects of lighting on humans. Furthermore, the implications for research and practice offer valuable insights for the development of innovative lighting technologies and strategies aimed at enhancing the well-being and experiences of individuals worldwide. This work highlights the relevance of interdisciplinary research involving fields such as architecture, business management, event management, computer science, design, engineering, ergonomics, lighting research, medicine, physics, and psychology in advancing our understanding of visual and non-visual lighting effects.