When most people think of students’ wellbeing and achievement, thermal comfort, lighting and air quality come to mind. Another, perhaps less obvious, factor affecting student wellbeing is acoustics, and research shows clear correlations between excessive classroom noise and impaired student performance.
“The brain has a hard time focusing on what it needs to when there are poor acoustics, and that causes cognitive dissonance, or mental discomfort,” says Sue Ann Highland, Ph.D., industrial/ organizational psychologist and national education strategist for School Specialty, a Greenville, Wis.-based organization whose mission is to engage and inspire classrooms with everything from crayons to curriculum. “Improving acoustics in the classroom can truly help students achieve.”
Learning is a significant part of the educational experience, but classrooms also offer students the opportunity for personal growth, socialization, creative outlet and emotional relief—all of which affect mental health. Sound can impact these areas of student development, as well, which is increasingly critical in times of trauma.
Noise is distracting, and sounds affecting students originate from two main sources. Environmental sounds are those outside the classroom, such as noise from transportation (cars, trains or airplanes), landscaping equipment, playground commotion, and sounds from school hallways and adjacent classrooms. Other sources of sound are found within the classroom, like the noise from the ventilation system and students’ voices.
Soundwaves reflect off hard surfaces and bounce back, lingering in a space. This process is called reverberation. Schools are commonly built with hard-surface materials able to with- stand wear and tear, like brick, glass, tile, linoleum and gypsum walls. With most hard surfaces, nearly 90 percent of soundwaves bounce back into the space, making for long-lasting reverberations that can be difficult for the brain to interpret. This is especially challenging when the reverberations mix with soundwave reverberations produced by other sources, like environmental noise or speech.
The World Health Organization guidelines for reverberation times in classrooms is 0.6 seconds. On average, the typical classroom of 960 square feet has a reverberation time of 1.9 seconds, three times longer than recommended.
Research reveals excessive noise and reverberation can negatively affect a child’s behavior and students’ ability to learn. Chronic noise exposure affects children’s performance in multiple ways, from deficits in attention and memory for certain tasks to reduced reading ability and performance on standardized tests. For students with speech, hearing or attention problems, or those who are concurrently learning English as a second language, the effects of poor classroom acoustics become even more challenging.
The younger the child, the lower the reverberation time needs to be. Auditory systems of young children aren’t fully developed. When learning a new subject, like math, and trying to grasp unfamiliar terms in a noisy classroom environment, young children tend to disengage and essentially “shut down.”
Reverberating sound or excessive environmental noise can also prevent students from properly understanding the teacher. Distance from the source of sound plays a role too. In noisy classrooms, students seated in the fifth row have 50 percent less speech intelligibility than those who sit in the front row.
“When you’re in a classroom with hard surfaces and students are spread out, some students can’t even hear what the teacher is saying,” Highland says. “Cognitive tasks requiring high levels of concentration are very sensitive to noise, and constant interruption from sound disturbs one’s ability to think. This is something educators don’t even consider because we aren’t taught to recognize the impacts of poor acoustics.”
Students aren’t the only ones affected by this issue. Intuitively, people talk louder over accumulated noise to be heard. Teachers must speak at least 15 decibels over the ambient noise for students to hear and understand them. The result is vocal strain.
“Eighty percent of teachers say they have experienced vocal fatigue because they have to speak up so loud to be heard,” explains Slavi Younger Nightingale, co-founder and vice president of Marketing at Fräsch, a manufacturer of acoustical solutions. “Our hearing developed as a survival tool, and we pay special attention to sound changes in our environment. Unfortunately, our systems aren’t very good at filtering out dynamic sounds or at choosing to focus on one specific human voice.”