Robust Effects of Working Memory Demand during Naturalistic Language Comprehension in Language-Selective Cortex

Area of Science:

• Neuroscience
• Cognitive Science
• Psycholinguistics

Background:

• Understanding language requires inferring meaning from real-time signals.
• Working memory (WM) and surprisal (word predictability) are debated mechanisms in language processing.
• Previous studies controlling for surprisal showed mixed results regarding WM's role.

Purpose of the Study:

• Investigate WM demand during naturalistic language comprehension, controlling for surprisal.
• Determine if WM mechanisms in language are language-specialized or domain-general.
• Examine neural correlates of WM demand in language processing.

Main Methods:

• Functional magnetic resonance imaging (fMRI) study.
• Naturalistic language comprehension task (story listening).
• Controlled for word surprisal and localized language and multiple-demand networks.

Main Results:

• Found significant WM demand effects in the language network, independent of surprisal.
• Observed no WM demand effects in the multiple-demand network.
• WM demand during language comprehension is associated with language-selective brain regions.

Conclusions:

• Language comprehension involves computationally demanding structure building in WM.
• WM operations in language processing are primarily handled by language-specialized neural resources.
• Findings support a core role for WM in incremental language processing, distinct from domain-general WM systems.