Linguistic structure across time: ERP responses to coordinated and uncoordinated noun phrases

Relatively little is known about how linguistic structure is neurally encoded. The current study examines a relatively subtle structural manipulation: the difference between reading a list of two noun phrases (“sunlit ponds ### green umbrellas”) and their syntactic coordination (“sunlit ponds and green umbrellas”). In two ERP experiments, the presence of the coordinator resulted in an increased anterior negativity across the entire second noun phrase, even though coordination had no direct relevance for the memory recognition task. These findings demonstrate that structural connectedness exerts strong, ongoing neural processing differences even when structured and unstructured materials are very tightly matched in sequence and content. More specifically, the results are consistent with the hypothesis that linguistic structure is automatically and actively maintained in memory across the course of a sentence; alternatively, the sustained anterior negativity may reflect computation of the more complex semantic or discourse representation associated with a longer connected structure.