Tutorial: Theoretical Considerations When Planning Research on Human Factors in Lighting

Abstract

Research on human functioning is notoriously difficult. This particularly holds for the study of light effects, at least if one wants to go beyond establishing that changes in light "have an effect" and understand why this effect occurs-in other words, if one wants to make causal inferences about the mechanism behind it. The latter is, of course, crucial for generalizing insights and being able to use them effectively in other contexts. The culmination of many decades of research has taught us that light affects psychological functioning in numerous ways and through various pathways. This implies that, regardless of the investigator's particular interests in either of those mechanisms, generally all will be at play, simultaneously, for participants in any lighting study. The present tutorial aims to address this complexity and how to deal with it by concisely describing the most important pathways that we currently are aware of. Such awareness is important both in contemplating the design and methodology of a study and in interpreting results from other studies and generalizing them to a particular application or light design. ARTICLE HISTORY

LED Light Sources and Their Complex Set-Up for Visually and Biologically Effective Illumination for Ornamental Indoor Plants

“…Therefore, the green foliage found in nature seems to be associated with a peak in photopic luminosity function at 555 nm (green) [37]. [38].…”

“…11, x FOR PEER REVIEW 9 of Two types of human vision based on different levels of visible light. Source: authors' own figure based on de Kort (2019)[38].…”

“…Three types of cones in the human eye (S, M and L) which are sensitive to different wavelengths of visible light. Source: authors' own figure based on de Kort (2019)[38].…”

How to Report Light Exposure in Human Chronobiology and Sleep Research Experiments

“…This article is also not a standard in the regulatory sense, and does not arbitrate between different models of circadian phototransduction (e.g., [10,11]). For readers wishing to expand their knowledge of ancillary topics, we recommend consulting recent reviews on the effects of light on circadian rhythms, sleep and cognition [12,13], colour vision and colorimetry [14,15], lighting and human factors [16], field studies of light exposure [17], and photometry [18]. We have written this article for human chronobiology and sleep research experiments, but similar principles apply for experiments with animal models.…”

Video Analysis of Pedestrian Movement (VAPM) under Different Lighting Conditions—Method Exploration

“…This also applies to the understanding of people's walking habits in urban environments [19]. Therefore, the evaluation of lighting applications is challenging, considering the complexity of human interaction with lighting and the lit environment; for an overview of this issue, see [20]. Drawing on a user perspective on the built environment, researchers have proposed that outdoor lighting applications should include three overarching categories of human responses, which involve different but interlinked psychological processes: pedestrian perception, evaluation and behaviour in the lit environment [21].…”