Effects of classroom reverberation time on speech perception and noise ratings in elementary school children

Current results from field and laboratory studies document the negative effects of adverse room acoustics on speech perception and cognitive performance in children. Within this project, the effects of classroom acoustics on noise judgments and mental performance in first- and second-graders were analyzed. The study was carried out as an interdisciplinary cooperation by psychologists and acousticians. The sample consisted of 487 children from 21 classrooms located in the Stuttgart area. During sample recruitment, particular attention was given to classroom reverberation times. Long reverberation times impair speech intelligibility and cause an increase in background noise, since all sounds linger in the room. In each school, one classroom was equipped with sound-absorbing materials in order to achieve favourable reverberation times of about 0.5 s. Acute effects of reverberation on children.s listening performance were assessed by comparing performance in this extra-room with performance in the original classroom. Significant effects of reverberation time were found for the children.s performance in a phoneme discrimination task. Given the task was administered in the extra-room, roughly a 10% increase in performance was discovered for first-graders usually instructed in classrooms with long reverberation. Furthermore, we found significant effects of reverberation times on the classroom noise pupils report to be exposed to. Children instructed in rooms with long reverberation times feel more annoyed by noise than children taught in classrooms with favourable acoustics. The findings underline the importance of good classroom acoustics for efficient and successful learning.