Light enriched with a blue component accelerated thinking, improved concentration, and increased perceived alertness in students, as demonstrated by German scientists.

About study

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Title:	Influence of blue-enriched classroom lighting on students׳ cognitive performance
Author:	Oliver Keis, Hannah Helbig, Judith Streb, Katrin Hille ZNL Transfer Center for Neuroscience and Learning, University of Ulm, Germany
Date:	10. September 2025
Source:	http://dx.doi.org/10.1016/j.tine.2014.09.001

Brief summary

Results of the German study showed that students exposed to blue-enriched light achieved better attention test scores, faster cognitive processing, and also felt more alert. The research was conducted in two schools: one classroom was equipped with LED lighting with a higher proportion of blue, closer to daylight, while the control classroom remained under standard warm white fluorescent lighting. The study’s findings confirm that circadian-optimized lighting can be an effective means of alleviating so-called social jet lag, which students often experience. This condition occurs when the biological need for sleep is out of sync with societal demands, leading to accumulated sleep debt, fatigue, and decreased cognitive performance. Light appears to be a significant factor capable of supporting cognitive function.

Light Enriched with Blue Component Enhanced Cognitive Speed and Concentration in Students

The study demonstrated significant positive effects of white light with a higher proportion of blue on adolescents’ cognitive performance. Compared to standard lighting conditions, students showed faster cognitive processing, higher levels of concentration, and simultaneously lower error rates. Analysis of differences between pre-test and post-test confirmed that exposure to blue-enriched light led to a more pronounced improvement in performance than exposure to standard warm white lighting.

Students Exposed to Blue-Enriched Light Felt More Alert

Participants were asked to complete questionnaires evaluating lighting comfort, brightness, and color. Standard fluorescent light was generally rated more favorably in terms of comfort. However, approximately half of the students indicated that they would prefer blue-enriched light because it made them feel more alert.

Our note: A higher correlated color temperature can support cognitive functions, but the spectral composition and sufficient intensity are crucial. Light synchronizes our internal clocks through photosensitive retinal ganglion cells, which detect day and night phases based on the azure region of the spectrum around 480 nm. The red component should not be neglected either, as it protects the eyes and improves visual comfort and mood in the space.

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