Cortical Tracking of Continuous Speech Under Bimodal Divided Attention

Zilong Xie*, Christian Brodbeck, Bharath Chandrasekaran*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Speech processing often occurs amid competing inputs from other modalities, for example, listening to the radio while driving. We examined the extent to which dividing attention between auditory and visual modalities (bimodal divided attention) impacts neural processing of natural continuous speech from acoustic to linguistic levels of representation. We recorded electroencephalographic (EEG) responses when human participants performed a challenging primary visual task, imposing low or high cognitive load while listening to audiobook stories as a secondary task. The two dual-task conditions were contrasted with an auditory single-task condition in which participants attended to stories while ignoring visual stimuli. Behaviorally, the high load dual-task condition was associated with lower speech comprehension accuracy relative to the other two conditions. We fitted multivariate temporal response function encoding models to predict EEG responses from acoustic and linguistic speech features at different representation levels, including auditory spectrograms and information-theoretic models of sublexical-, word-form-, and sentence-level representations. Neural tracking of most acoustic and linguistic features remained unchanged with increasing dual-task load, despite unambiguous behavioral and neural evidence of the high load dual-task condition being more demanding. Compared to the auditory single-task condition, dual-task conditions selectively reduced neural tracking of only some acoustic and linguistic features, mainly at latencies >200 ms, while earlier latencies were surprisingly unaffected. These findings indicate that behavioral effects of bimodal divided attention on continuous speech processing occur not because of impaired early sensory representations but likely at later cognitive processing stages. Crossmodal attention-related mechanisms may not be uniform across different speech processing levels.

Original languageEnglish (US)
Pages (from-to)318-343
Number of pages26
JournalNeurobiology of Language
Volume4
Issue number2
DOIs
StatePublished - 2023

Keywords

  • acoustic processing
  • continuous speech
  • crossmodal
  • divided attention
  • EEG
  • linguistic processing

ASJC Scopus subject areas

  • Linguistics and Language
  • Neurology

Fingerprint

Dive into the research topics of 'Cortical Tracking of Continuous Speech Under Bimodal Divided Attention'. Together they form a unique fingerprint.

Cite this