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Development and bilingual influences of neural systems for syntactic ambiguity resolution
Poster Session C, Thursday, October 1, 10:45 am - 12:45 pm, Wangari Maathai
Noelani Kong-Johnson1,2, Kamil Deen1; 1University of Hawaii at Manoa, 2Georgetown University
Syntactic ambiguity resolution requires coordination between language and cognitive control systems to resolve competition between alternative interpretations. Although these abilities continue to develop throughout childhood, it remains unclear whether different forms of ambiguity rely on overlapping but distinct developmental trajectories, and how bilingual experience shapes the neural organization of these processes. The present study investigated developmental and bilingual influences on the neural systems supporting syntactic ambiguity resolution using fMRI. English-Hawaiian bilinguals and English monolinguals (children 5-10 years-old and adults) completed two auditory syntactic ambiguity tasks during fMRI scanning: (1) an action verification task requiring revision of an initially preferred interpretation during garden-path sentence processing, and (2) a picture selection task requiring selection between competing interpretations that can be maintained in parallel during prepositional phrase attachment ambiguities. Functional analyses examined ambiguity-related activation and developmental effects associated with revision-specific processing (post-critical > pre-critical word activation during garden-path processing) and global ambiguity resolution across language groups. Across tasks, ambiguity resolution recruited overlapping regions within a shared language-control network, including inferior frontal, temporal, parietal, medial frontal, and subcortical regions. However, the two ambiguity types differed in how this network reorganized over development. In the action verification task, age-related increases emerged in inferior frontal gyrus (IFG), anterior cingulate cortex (ACC), medial frontal, parietal, and subcortical regions during revision-specific processing, consistent with increasing engagement of control-related systems supporting reanalysis and conflict resolution. Although both groups showed developmental increases, bilinguals exhibited stronger age-related recruitment of medial frontal and ACC regions, whereas monolinguals showed greater increases in temporo-parietal regions, suggesting partially distinct developmental routes toward successful revision. The picture selection task showed a different developmental pattern. Bilinguals demonstrated age-related decreases in activation across frontal, temporal, medial frontal, and subcortical regions, whereas monolinguals showed limited age-related effects. Unlike the revision demands of the action verification task, the picture selection task allowed competing interpretations to be maintained and resolved without reanalysis. Reduced activation in bilinguals may therefore reflect decreased reliance on distributed control-related systems as parallel maintenance and selection processes become more efficient over development. Despite broadly comparable behavioral performance across language groups, bilingualism modulated the recruitment of control-related systems depending on task demands. Increased engagement emerged in contexts requiring revision, whereas reduced distributed recruitment emerged when competition could be maintained and resolved without reanalysis. This pattern suggests that bilingual experience may reorganize the language-control system toward more efficient maintenance and selection among competing interpretations when revision is unnecessary, while preserving the engagement of control-related systems when controlled reanalysis is required. Together, these findings support a model in which syntactic ambiguity resolution emerges from multiple, developmentally distinct mechanisms within a shared language-control architecture that is shaped by experience.
Topic Areas: Language Development/Acquisition, Multilingualism