Working memory constraints on syntactic processing: An electrophysiological investigation

Item does not contain fulltextERPs and RTs were used to study how the processing of sentences with morphosyntactic violations is constrained by working memory (WM) capacity. The available WM capacity was varied by three orthogonal manipulations: 1) syntactic complexity; 2) additional WM load; 3) verbal WM span. The processing of the morphosyntactic violations was reflected in longer RTs in ungrammatical than in grammatical sentences, and in an anterior negativity and a centro-parietal positivity in the ERPs. While the behavioral grammaticality effect was not influenced by the WM manipulations, the ERP effects were. The amplitude of the anterior negativity was modulated by the combination of complexity and load, and by WM span. The onset of the centro-parietal positivity was delayed in the high load condition, and for the low span group. ERPs over the course of the sentences showed a frontal negative slow wave under high WM load, largest for the low span group. The finding that on-line syntactic processing is related to WM span and to additional WM load, does not support the theory that there is a WM capacity specific for syntactic processing