Full-Spectrum Fluorescent Lighting Effects on People: A Critical Review

Full-spectrum fluorescent lighting has been credited with causing dramatic improvements in a wide variety of behaviours, mental health outcomes, and physical health effects. These effects include reduction in dental caries, improved classroom behaviour in schoolchildren, enhanced academic achievement, more efficient visual performance, more attractive appearance of both people and spaces, and improved mood in cases of seasonal depression. Popular media reports have tended to emphasize studies that have demonstrated differences in outcomes as a function of light source spectral power distribution. However, the scientific literature also includes reports with null and contradictory effects. This comprehensive review covers the period 1945-1993 and includes a critical appraisal of the methodology in each study. The studies are grouped according to their dependent variables under the broad headings "Behaviour and Performance", "Mental Well-Being and Affect", and "Physiology and Health". In general, the quality of the research is poor, making it difficult to determine whether or not treatment effects may legitimately be attributed to light source spectral power distribution. A few rigorous investigations of full-spectrum fluorescent lighting have demonstrated small effects; however, few researchers have taken up the challenge to replicate their work. These small effects do not support the claims that full-spectrum fluorescent lighting will produce better performance, mood, or health in the general population. More fruitful avenues for future research include investigations of other lighting parameters including intensity, variability, and flicker and an emphasis on the possibility that individual differences exist in sensitivity to the spectral composition of light sources. The role of mental processes -for example, beliefs, memories, and expectations -in mediating the effects of lighting on behaviour stands out as most promising for future research.