Syntactic Adaptation Following Short Term Experience: Neural Correlates and Relationship to Cognitive Control Open Access
Downloadable ContentDownload PDF
How do individuals adapt to linguistic variability? Previous studies have shown improved syntactic processing of infrequent structures following short-term exposure (Fine et al., 2013; Wells et al., 2009). However, the relevant mechanisms and neural substrates are unknown. We hypothesized that if adaptation is driven by detection of a mismatch between the predicted and actual structure, then cognitive control mechanisms for conflict resolution may be involved. If so, adaptation could be sub-served by frontal regions linked to both comprehension and cognitive control - the anterior cingulate cortex (ACC) and the left pars opercularis (ParsOp), and the extent of this adaptation might correlate with individual differences in cognitive control (as indexed by Stroop). This study investigated exposure-based adaptation in garden-path sentence comprehension. Participants (N=28) underwent three runs of functional neuroimaging (fMRI): pre-exposure, exposure to unexpected syntactic structures, and post-exposure. Both neural and behavioral results demonstrate improved processing of infrequent structures over the course of exposure. The pattern of adaptation was modulated by the prediction error between predicted and actual structures, consistent with an error-based learning mechanism. Both neural and behavioral effects suggest some verb-specificity in learning, with more persistent ambiguity effects for unexposed than exposed verbs. These changes were detected in left ParsOp, but not ACC. Finally, correlation between ParsOp adaptation and Stroop suggests that adaptation was related specifically to individual differences in cognitive control.