Poor Listening Conditions Impair Memory for Intelligible Lectures: Implications for Acoustic Classroom Standards

This paper reports two experiments on the effects of degraded speech signals on memory for spoken lectures. Experiment 1 showed that broadband noise impairs university students' memory for a spoken lecture, even though the participants heard what was said. Experiment 2 showed that reverberation has detrimental effects to school adolescents' memory for spoken lectures, similar to broadband noise. The results suggest that poor listening conditions (resulting from background noise and/or long reverberation time) impair memory and learning, even if the conditions allow the listeners to hear what is said. Since the goal for students and pupils attending to lectures is to remember the lecture rather than just hearing what is said, the results presented here indicate that standards for acceptable signal-to-noise ratios and reverberation times in buildings designed for learning should consider the distinction between speech intelligibility and memory. Standards should be based on memory criteria instead of intelligibility criteria.