The resolution of case conflicts from a neurophysiological perspective.

We present two ERP experiments examining the resolution of language processing conflicts involving the multidimensional linguistic feature case, which determines processing in both syntactic and interpretive respects. Ungrammatical German structures with two identically case-marked arguments (double subject or double object constructions) were tested. In earlier studies, double subject constructions have been shown to elicit a biphasic pattern consisting of an N400 effect (a marker of thematic integration problems) followed by a P600 effect (a marker of syntactic ill-formedness). Here, we compare double nominative (subject case) constructions with double datives (indirect object case; Experiment 1) and double accusatives (direct object case; Experiment 2). All types of double case ungrammaticalities elicited a biphasic N400-P600 response. However, double datives differed from double nominatives in that they elicited a larger P600, suggesting that the ill-formedness is more salient in structures with two dative arguments. Double accusatives, by contrast, elicited a stronger N400 in comparison to double nominatives, suggesting that they induce more severe semantic-thematic integration problems. The results demonstrate that the human language comprehension system is sensitive to fine grained linguistic distinctions between different cases and utilizes these in its attempts to solve processing conflicts.