Schools are another type of building that received the attention of ergonomists and where the contribution of day-lighting could be verifiably demonstrated. The architecture of school buildings can shape the way we teach and learn. In the five years between 2002 and 2007, more than 1000 schools were built each year in order to meet the demand of students in kindergarten and elementary schools in the United States alone. Architects and lighting ergonomists have taken a keen interest in the learning environment, particularly in the way children are affected by the natural and electric lighting conditions under which they study.
As a surrogate for daylighting, researchers explored the benefits of full spectrum fluorescent lighting. Some of the pioneering research in the learning environment came from John Ott, who was known for his work in the cinematic use of time-lapse photography. Ott's experiments with different colored lighting systems and their effects on the health of plants, humans, and later on individual cells using time-lapsed micro-photography set the standard. In 1973, he examined the effect of full spectrum lighting using four first-grade classrooms in Sarasota, Florida (Ott, 1973, 1976). Using two windowless classrooms with full spectrum fluorescent lighting and two identical windowless classrooms with standard fluorescent fixtures, he observed and compared student activities in the four classrooms using time-lapsed concealed cameras. Photographs revealed that students under cool-white standard fluorescent lights exhibited decreased attention and greater hyperactivity, fatigue, and irritability than students under full spectrum lights. Full spectrum lights were able to calm handicapped students who exhibited extreme hyperactivity. This study also found one-third fewer dental cavities in students working under full spectrum fluorescent lights. Previous research studies conducted in 1930 with a large number of children showed that the incidence of dental cavities related to the amount of sunlight that children were exposed to; the higher the exposure, the fewer dental cavities. In all likelihood the effect can be attributed to the presence of vitamin D through skin photosynthesis.
Harry Wohlfarth conducted a five-year study in Canada and confirmed that full spectrum lights lower stress, decrease absenteeism, and improve overall achievement in the classroom (Wohlfarth and Sam, 1982; Wohlfarth, 1984; Wohlfarth and Gates, 1985). He observed that blood pressure dropped an average of 20 points per child and aggressive behavior decreased significantly under full spectrum lights. To further confirm the real effect of full spectrum light, the fixtures were changed back to standard fluorescent fixtures. After the change, behavior deteriorated.
In a study of 90 Swedish elementary school students, cortisol (a stress hormone) levels were measured and followed during the course of a year in four classrooms with varying daylighting levels. The results indicate that classrooms without daylight tend to disturb the basic hormone pattern and this in turn influences student concentration. Researchers concluded that this hormone disturbance could eventually have an impact on annual body growth and absenteeism (Kuller and Lindsten, 1992).
A number of recent studies in the United States claimed a relationship between daylighting and enhanced student performance and incited interest among education officials and advocates of daylighting. One major study analyzed the test scores of more than 21 000 students in three school districts in three states: California, Colorado, and Washington (Heschong Mahone Group, 1999b). This study included a particular focus on skylighting as a way to isolate illumination effects from other qualities associated with daylighting from windows, such as view and ventilation. Student performance data were obtained from three elementary school districts and statistical correlation analyses between performance and the amount of daylight were performed. The results of standardized tests were used as performance indicators and data from second to fifth grades were used. Students in classrooms with the most daylight progressed 20% on math tests and read 26% faster in reading tests. Classrooms with the most window area were associated with a 15-23% faster rate of improvement in math and reading. Classrooms with skylights were associated with 19-20% faster rate of
improvement and classrooms with operable windows were associated with 7-8% faster improvement.
Another study measured the benefits of daylighting in schools in the Johnston County and Wake County School Districts in North Carolina (Nicklas and Bailey, 1996). The study compared the scores of students from newly constructed daylit schools with those from schools that relied primarily on electric lighting. One of the newly constructed schools, the Durant Middle School, was designed with a top lighting system using roof monitors (Figure 5.16). According to the designer of this project, the building was laid out along an elongated east-west axis to take advantage of the southern orientation for natural daylighting and winter passive solar gain through the continuous single-sloped roof monitors. Overhangs and interior baffles shield any direct sunlight, providing better quality diffuse daylighting.
The academic performance of children in the new day-lit classrooms was compared with student performance in other schools in the district that relied heavily on electric lighting. The results of the North Carolina study were similar to those found in the Heschong Mahone Group study. Students in the new daylit schools had higher reading and math achievement scores than students in buildings that relied heavily on electric lighting.
The results of these studies point to the positive effect of daylight in improving student learning. Whether this effect is due to chemical processes or physiological mechanisms remains to be investigated, but indications are clear that daylight influences learning in a very positive manner.
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