Clear speech adaptations and effortful speaking and listening in background noise across the lifespan

Abstract

Our study investigates strategies speakers use to clarify their speech and compensate for the impact of background noise in everyday settings. We recorded 114 individuals (8-80 years) while they carried out an interactive problem-solving task (diapix) in quiet, background speech and background non-speech noise. A secondary bell-press task was added to increase cognitive load. We measured (i) articulation rate, median fundamental frequency (f0) and intensity which reflect clear speech adaptations and speaking effort; (ii) subjective ratings of listening effort; and iii) secondary task performance reflecting distractibility (d-prime). Regardless of age, speakers increased their f0 and intensity more in non-speech noise than in quiet or background speech. However, they made more errors in the secondary task and reported greater listening effort when the background noise was speech. Older participants (>50 years) increased speaking effort in both noise types, but younger children (<13 years) increased speaking effort only in background speech. These results indicate that, in terms of speaking effort, background speech (more cognitively demanding) is effortful for children and older adults. However, background noise (more peripheral interference) is mostly effortful for older adults. In terms of listening effort and distractibility, we observed greater interference in background speech regardless of participant age.