JMIR Publications

ABSTRACT

Background:

Background noise is common in everyday environments, yet its effects on attention vary according to task demands, individual characteristics, and properties of the noise itself. Previous research has largely focused on music, non-speech noise, or intelligible speech, leaving the effects of paralinguistic components of human speech (e.g., tone, pitch, rhythm) difficult to separate from those linguistic content.

Objective:

This paper presents a structured experimental protocol designed to investigate whether paralinguistic characteristics of semantically inaccessible background speech conditions influence attention and cognitive performance. The goal is to develop a systematic, multimodal experimental framework that examines these effects while accounting for individual differences such as noise sensitivity, sleep quality, and working memory capacity.

Methods:

Adults aged 18 years or older (target N=50) will complete one 120-minute laboratory session. In a counterbalanced within-subject design, participants will perform attention-related tasks under three auditory conditions: silence, focused vocal stimuli, and diffused vocal stimuli. The primary outcome will be the concentration performance score of the d2 Test of Attention, and reading comprehension will be a secondary behavioral outcome. Pupillometry, electrodermal activity, and blood volume pulse will be recorded continuously, with mean pupil diameter, phasic electrodermal response rate, and the root mean square of successive differences designated as prespecified physiological outcomes. Individual differences will be assessed using measures of working memory capacity, noise sensitivity, ADHD symptomatology, sleep quality, and mood. The primary confirmatory analysis will use a linear mixed-effects model with auditory condition as a fixed effect, block position as a covariate, and participant as a random intercept. The prespecified primary contrast will compare focused and diffused vocal conditions at α=.05. Focused versus silence and diffused versus silence will be examined as secondary contrasts with Holm adjustment for multiple comparisons. Physiological outcomes will also be Holm-adjusted within their prespecified outcome family, while moderation analyses will be treated as exploratory. The protocol was refined following a formative pilot with 9 participants using an abbreviated two-block procedure.

Results:

Ethics approval was granted in June 2026. No participants have been recruited for the full study described in this protocol. Recruitment is scheduled to begin in April 2027, with data collection projected to conclude in March 2029 and data analysis expected to be completed by March 2030. Dissemination of the results is anticipated by March 2031.

Conclusions:

This protocol provides a reproducible approach for investigating whether paralinguistic characteristics of semantically inaccessible background speech influence attention and for examining accompanying physiological responses. The study will test whether attentional performance differs between focused and diffused vocal conditions and explore individual characteristics that may moderate these responses. The findings may inform future research on auditory distraction and the design of occupational and educational environments.