Opinion: Should lighting education consider more than people?

Sustainability is central in higher education, including lighting education, yet it is often treated as an optional addition rather than a foundation. Orr ¹ argued that all education is implicitly environmental education because its inclusions and exclusions signal to students which aspects of the natural world they are expected to consider. Lighting education is typically described as a multidisciplinary field that spans physics, design, engineering and environmental considerations. ² However, lighting programmes in practice tend to approach sustainability largely from a human-centred perspective, for example, visual comfort, indoor environmental quality, energy efficiency and lifecycle analyses. Ecological impacts of lighting design on other species or ecosystems are rarely addressed, despite being well documented in the scientific literature. Environmental content may appear in course descriptions but say little about the teaching staff’s ecological expertise. When teachers have little or no ecological training, students may gain some awareness of the problems but not the skills to act on them.

Lighting practitioners often seem to assume that lighting which looks dim, measures low in illuminance or is perceived as comfortable by humans is also ecologically harmless. This misconception is not simply a consequence of a lack of knowledge. Because human perception is our everyday reference point, the assumption that light which appears dim to us is also ecologically harmless easily becomes an unconscious default. Humans are a diurnal species whose vision is primarily adapted to photopic conditions, but many other organisms perceive and respond to light in fundamentally different ways, which means our own perception is not a reliable reference for understanding theirs. Nocturnal insects, for example, have highly sensitive visual systems and can discriminate colours at light levels where human colour vision ceases entirely. ³ The nocturnal elephant hawkmoth Deilephila elpenor can do so even in dim starlight (0.0001 cd m⁻²), where humans are fully colour-blind. ⁴ Differences in photopigment peak sensitivities and visual spectral responses across taxa ⁵ mean that lighting can disrupt navigation, reproduction and activity patterns in a wide range of species, ⁶ even when the spectrum or light level seems unproblematic to humans. Using human perception as the reference for judging ecological relevance is a clear example of anthropocentric bias. This perspective has not, to my knowledge, ever been examined in lighting practice, yet the consequence is a systematic failure to recognise and address ecological impacts.

This kind of anthropocentric bias is also rooted in automatic, intuitive cognitive processes operating as System 1 judgement, ⁷ functioning without deliberate reflection and captured in the assumption that what is not seen does not exist. This is particularly relevant for ecological impacts that occur at light levels below those humans can perceive (or while humans are asleep), and these impacts are therefore invisible to the very heuristic that judges what matters. Using human perception as a reference is rarely reflected upon because it feels self-evident and logical. Imagining how other species perceive light lies beyond the limits of human perception. Together, these cognitive predispositions result in a heuristic that leads professionals to underestimate ecological impacts. The issue is not ignorance or a lack of care, but a heuristic that feels intuitively correct and therefore rarely becomes questioned, even by experts.

However, the ecological impacts from outdoor lighting can have legal implications since outdoor lighting may negatively affect both protected species and habitats and thereby conflict with current environmental legislation, such as the Habitats Directive, ⁸ and international guidelines.^9,10 The cognitive predisposition that makes humans overlook ecological impacts does not free professionals from their legal responsibilities. Therefore, ecological competence needs to be a part of lighting education and should not be treated as an optional add-on or something that can be entirely outsourced to ecologists. Calls for transdisciplinary collaboration ¹¹ also assume that lighting professionals can identify and recognise when ecological expertise is needed, a competence that current education does not necessarily provide in enough depth.

Ecological content needs to be a substantial part of lighting education and extend beyond brief theory or simple basics. Understanding that other species perceive light fundamentally differently conflicts with everyday human experience and is therefore difficult to fully internalise. Meyer and Land ¹² would describe this as troublesome knowledge because it conflicts with students’ existing understanding of light and perception. This learning process is transformative ¹³ because students begin to interpret lighting and environmental impact differently. Recognising that organisms respond to light levels far below human perception can function as a threshold concept. ¹² Once the threshold is crossed, students begin to understand lighting as an ecological factor rather than only a human-centred one. Before that insight, students continue using human perception as their primary reference and may overlook ecological effects of lighting.

The solution is not to turn lighting students into ecologists. However, it is reasonable to expect that future lighting professionals should be able to recognise when and where environmental impacts are significant, to know that certain groups of organisms are particularly photosensitive (e.g. bats, nocturnal birds, moths, amphibians) and to know when specialist expertise is required. This also requires enough understanding to critically evaluate new scientific findings independently. Without this knowledge, lighting professionals become dependent on others to identify what is ecologically relevant and may lack the ability to apply ecologically respectful lighting independently.

One way to support this threshold crossing is to build ecological considerations directly into assessment. In a lighting science course I taught, students built on earlier coursework and read scientific ecological literature on the effects of outdoor lighting. They were then given a scenario involving a genuine conflict between human needs for outdoor lighting and photosensitive organisms, including protected species. The task required them to evaluate trade-offs and justify their design decisions in relation to ecological impact. The assignment was designed to make students question the use of human visual perception as the main reference for lighting quality. It was a difficult assignment with no straightforward solution. Several students initially approached the task entirely from a human-centred perspective before recognising ecological constraints they had not previously considered. Most students engaged seriously and arrived at reasoned proposals, with some concluding that the most responsible choice was not to introduce lighting at all, judging that even carefully designed solutions could pose unacceptable risks to protected species. These decisions reflected a high level of professional integrity, where students were willing to question assumptions, weigh competing priorities and accept that not all situations call for a technical solution. When environmental impact was integrated into the judgement of lighting design quality, ecological reasoning shifted from a peripheral concern to a central part of professional competence. Students moved from an intuitive, anthropocentric view to a biologically informed understanding of light as an ecological factor.

If lighting education continues to prioritise a human-centred curriculum without adequately addressing ecological consequences, future professionals may remain highly skilled in technical and design aspects while still creating unintended ecological harm or having to rely on ecologists to determine important aspects of the lighting design.

The question, therefore, is whether lighting education should consider more than people by making ecological knowledge a mandatory part of the curriculum, not an elective or marginal addition, but a requirement on the same level as human-centred design. Lighting that works well from a human-centred perspective is not automatically ecologically respectful. Recognising this, and being able to act on it, should be considered a core competence in lighting education.