Why We Should Consider the Hawthorne Effect Before We Decide to Fortify the Physical School Environment

What is often overlooked, or greatly under-estimated, when planning to fortify the physical environment of a school is the impact those changes will have upon students – and ultimately student learning and student performance.  As communities demand steel doors and fewer windows in schools it is important to weigh those changes against the potential impact on students.

What is the Hawthorne Effect?

From 1924-1932, there were a number of experiments at the Hawthorne Works factory outside Chicago.  Hawthorne Works had commissioned a study to see if its workers would become more productive in higher or lower levels of light.  The workers’ productivity seemed to improve when changes were made and slumped when the study was concluded.  It was suggested that the productivity gain occurred due to the impact of the motivational effect on the workers as a result of the interest being shown in them.  Although the Hawthorne experiments are largely recalled for the impact on light on productivity, there were other experiments conducted which included changing break times and frequencies, providing food during breaks and shortening the school work day.  A flaw in the Hawthorne studies was that very few workers were included in the experiments, often fewer than 10.  Therefore, reliability and validity are obviously suspect and at best the researchers can state observations and possible relations between variables (although this wasn’t a completely controlled environment – not all variables accounted for…).

Nevertheless, from the Hawthorne studies, and other studies, it is known that subjects modify their behavior in response to changes in their environment, including an awareness that they are being studied.

The Impact of Natural Light on Learning – Key Findings of a 1999 Study of the Impact of Daylight in Schools

The following excerpts were taken directly from the article Study says natural light boosts learning by Kenneth J. Cooper, Washington Post, 11/26/1999 and from the report Daylighting in School – An Investigation in the Relationship Between Daylighting and Human Performance (139-page detailed report submitted by the Heschong Mahone Group to the California Board for Energy Efficiency Third Party Program, August 20, 1999)

The purpose of the Heschong Malone Group study was to look for a clear relationship between human performance in buildings and the presence of daylight.  This study analyzed test scores of 21,000 students from three districts, located in Orange County, California; Seattle, Washington and Fort Collins, Colorado.  The researchers analyzed daylighting conditions in over 2000 classrooms.

The study found that students who took their lessons in classrooms with more natural light scored up to 25 percent higher on standardized tests than other students in the same school district. The study, billed as the first rigorous one of its kind, appears to confirm what some school designers have asserted based on anecdotal evidence: children learn better under illumination from skylights or windows, rather than light bulbs. The main theories for why this might be the case are that ”daylighting” enhances learning by boosting the eyesight, mood and/or health of students and their teachers.

The study’s central finding runs counter to a theory of school design popular in the 1970s – eliminating classroom windows so that students would not be distracted.  Facility managers also contended that windows and skylights were a maintenance and security risks.  Since the 1970s, many classrooms have little daylighting and some have no windows at all.


The Swedish researchers followed the health, behavior, and hormone levels of 88 eight year old students in four classrooms over the course of one year. The four classrooms had very different daylight and electric light conditions: two had daylight, two had none; two had warm white (3000K) fluorescent lamps, two had very cool (5500K) fluorescent lamps. The researchers found significant correlation between patterns of daylight levels, hormone levels, and student behavior, and concluded that windowless classrooms should be avoided

Kuller, R and Lindsten, C “Health and Behavior of Children in Classrooms with and without Windows”, Journal of Environmental Psychology, (1992) 12, 305-317. Further discussed in Section 5.1.4.

Before we replace windows with bricks and glass doors with steel doors – let’s carefully consider the full consequences of those actions.