Effects of human-centric lighting on performance in the attentional network test (ANT) and on perceived stress

The evidence on the short-term effects of light on cognition is inconsistent. Within the framework of the human-centric lighting approach, such effects could be used to enhance well-being and performance. To address this question, we conducted a one hour laboratory study with 789 participants, examining the impact of bright daylight white light (BL; 517.0 lx, 5417 K), warm-white light (WL; 67.5 lx, 2628 K), and neutral light (NL; 160.8 lx, 4133 K) on the scales of the Attention Network Test (ANT). The effects observed were small in magnitude. For your attention, only a small, insignificant effect emerged, with WL yielding the poorest performance. In contrast, the scale alerting showed a significant medium effect, with fastest responses under BL and slowest under WL. For the scale orienting, a small significant effect was found, with WL producing the best performance. BL emerged as the most beneficial condition overall, particularly enhancing the alerting component. In contrast, WL was repeatedly associated with negative effects on both scales alerting and executive attention. Unexpectedly, WL showed advantages in the orienting component, suggesting complex underlying mechanisms that are not yet fully understood. Future studies should examine lighting programs with greater contrast and incorporate physiological measures (e.g., pupillometry, EEG) as well as more differentiated psychological assessments. To explain these findings, the development of integrative models - such as the HCL-effect model proposed by Wessolowski - is essential. Light is more than a visual stimulus; it modulates attention and cognition. This insight should be systematically considered in the design of work, learning, and living environments.