Natural Light Influence on Intellectual Performance. A Case Study on University Students

Natural light in interior spaces has many advantages: the most obvious is energy savings, but also many long term physical and mental health benefits. Published research demonstrates the positive effects of natural light, especially in spaces used in long term periods, such as offices, houses, hospital rooms, etc. However, how would the deprivation of natural light affect users in spaces of more occasional use, such as lecture theatres, surgery rooms, courtrooms…? The present research consists in a case study that adds some data on that question. The experiment processed the data on the performance of 278 university students in one theoretical course, consisting in three-hour weekly lectures. This course was taught six times, in six consecutive years (2013–2018), three in exclusively artificially lit basement classrooms, and the other three in classrooms with windows, mixing natural and artificial light. The data of the exam and attendance scores were compared statistically for both populations (basement vs. windows classrooms). The research found strong evidence of the classrooms with windows having better exam scores than those in the basement, with mean differences between 13.17% and 7.73%. Mann–Whitney U tests supported this result, with p -values ranging between p << 0.001 and p = 0.007. Attendance differences were not significant.