Lighting in the classroom can be seen as the most influential part of a physical learning environment as it is the “most important environmental input, after food and water, in controlling bodily functions” (Wurtman as cited in Tanner, 2008). This is because lights have an influence on blood pressure, pulse, respiration and brain activity. Specifically, full-spectrum light is crucial in the pineal gland’s production of melatonin, which helps in secretion of the neurotransmitter serotonin – all of which is “critical to a child’s health and development” (Tanner, 2008, p.385). In addition to this, natural daylight is essential to regulating the body’s circadian rhythms. As a result, Tanner (2008) suggests replacing standard fluorescent bulbs with full-spectrum bulbs, which are nearly equivalent to the sun’s wavelengths. Because without this lighting and in windowless classrooms, students will be under a form of fatigue similar to jet lag which consequently affects ability to learn (Tanner, 2008).

A study following students in California, Washington, and Colorado for a year compared student performance on mathematics and reading tests in relation to daylight levels. In consensus with the above discussion, these researchers found that students in classrooms with higher levels of day lighting performed better in both subject areas compared to students in classrooms with less day lighting. The same results were found when comparing performance in the two subjects between students in classrooms with larger windows and classrooms with smaller windows. This positive affect of windows on learning results from both exposure to natural lighting and formation of a connection between the student and the outside. That is, there is an opportunity to view outside of the classroom, an opportunity to “rest the eyes” as doing this enhances the general “well being of students and teachers” (Tanner, p.387, 2008).