Cognitive resources are distributed among the entire auditory landscape in auditory scene analysis

• Published in: Psychophysiology 2020-02, Vol.57 (2), p.e13487-n/a
• Main Authors: Symonds, Renee M., Zhou, Juin W., Cole, Sally L., Brace, Kelin M., Sussman, Elyse S.
• Format: Article
• Language: English
• Subjects: Adult; Attention; Attention - physiology; Auditory Perception - physiology; auditory scene analysis; Cognitive ability; cognitive load; Electroencephalography; Electrooculography; ERPs; Event-related potentials; Event-Related Potentials, P300 - physiology; Evoked Potentials - physiology; Evoked Potentials, Auditory - physiology; Executive Function - physiology; Female; Frequency dependence; Hearing; Humans; Male; Mismatch negativity; mismatch negativity (MMN); P3b component; Sound; Visual Perception - physiology
• ISSN: 0048-5772; 1469-8986; 1540-5958
• DOI: 10.1111/psyp.13487

Although attention has been shown to enhance neural representations of selected inputs, the fate of unselected background sounds is still debated. The goal of the current study was to understand how processing resources are distributed among attended and unattended sounds during auditory scene analysis. We used a three‐stream paradigm with four acoustic features uniquely defining each sound stream (frequency, envelope shape, spatial location, tone quality). We manipulated task load by having participants perform a difficult auditory task and an easy movie‐viewing task with the same set of sounds in separate conditions. The mismatch negativity (MMN) component of event‐related brain potentials (ERPs) was measured to evaluate sound processing in both conditions. We found no effect of task demands on unattended sound processing: MMNs were elicited by unattended deviants during both low‐ and high‐load task conditions. A key factor of this result was the use of unique tone feature combinations to distinguish each of the three sound streams, strengthening the segregation of streams. In the auditory task, the P3b component demonstrates a two‐stage process of target evaluation. Thus, these results, in conjunction with results of previous studies, suggest that stimulus‐driven factors that strengthen stream segregation can free up processing capacity for higher‐level analyses. The results illustrate the interactive nature of top‐down and stimulus‐driven processes in stream formation, supporting a distributive theory of attention that balances the strength of the bottom‐up input with perceptual goals in analyzing the auditory scene. Attentional resources are generally thought of as preferentially distributed to the task at hand. We demonstrated complex sound processing within unattended and attended sound streams in parallel and irrespective of the task load demand. Results thus demonstrate that the task load is not necessarily a defining factor in limiting attentional resources. Our results support a distributive theory of attention that balances the strength of the bottom‐up input with perceptual goals in analyzing the auditory scene.