The effect of unintelligible speech noise on children's verbal working memory performance

Classroom noise, particularly speech noise from students, appears to disrupt verbal working memory processes essential for learning tasks such as reading and writing. Such negative interference has been alternatively explained as either the effect of phonological intrusion from speech noise into the phonological loop processes of working memory or the diversion of general attentional resources away from working memory processes. These effects have been studied primarily in relation to intelligible speech, while the impact of unintelligible speech, such as multitalker babble-a common source of noise in schools-has received less attention. The present study aimed to examine the effects of unintelligible multitalker babble noise on the performance of 38 students aged 8 to 10 years in low (Digit Span) and high demanding (Reading Span) verbal working memory tasks. We examined whether the effects of multitalker babble noise differed based on children's age and their visual attentional resources. Verbal working memory and visual attentional skills were assessed in quiet and multitalker babble noise across three age groups: 8, 9, and 10 years. Our findings revealed that multitalker babble noise disrupts significantly verbal working memory performance in complex verbal working memory tasks, like the Reading Span task, but has minimal impact on low demanding tasks, like Digit Span Forward and Backward. Although children's visual attentional skills significantly contributed to their verbal working memory performance, they alone cannot explain the negative effect of multitalker babble noise. Interestingly, although children's behavioral performance did not significantly differ across acoustic conditions for most tasks, they reported higher cognitive effort in noisy environments. This highlights a discrepancy between perceived effort and actual performance, emphasizing the importance of integrating multiple measures to assess the impact of noise on cognitive processes.