Publications

Abstract

In 3 ERP experiments, we investigated how experienced L2 speakers process natural and correct syntactic input that deviates from their own, sometimes incorrect, syntactic representations. Our previous study (Lemhöfer, Schriefers, & Indefrey, 2014) had shown that L2 speakers do engage in native-like syntactic processing of gender agreement but base this processing on their own idiosyncratic (and sometimes incorrect) grammars. However, as in other standard ERP studies, but different from realistic L2 input, the materials in that study contained a large proportion of incorrect sentences. In the present study, German speakers of Dutch read exclusively objectively correct Dutch sentences that did or did not contain subjective determiner “errors” (e.g., de boot “the boat,” which conflicts with the intuition of many German speakers that the correct phrase should be het boot). During reading for comprehension (Experiment 1), no syntax-related ERP responses for subjectively incorrect compared to correct phrases were observed. The same was true even when participants explicitly attended to and learned from the determiners in the sentences (Experiment 2). Only when participants judged the correctness of determiners in each sentence (Experiment 3) did a clear P600 appear. These results suggest that the full and native-like use of subjective grammars, as reflected in the P600 to subjective violations, occurs only when speakers have reason to mistrust the grammaticality of the input, either because of the nature of the task (grammaticality judgments) or because of the salient presence of incorrect sentences.

Abstract

Motor cortex activation observed during body-related verb processing hints at simulation accompanying linguistic understanding. By exploiting the up- and down-regulation that anodal and cathodal transcranial direct current stimulation (tDCS) exert on motor cortical excitability, we aimed at further characterizing the functional contribution of the motor system to linguistic processing. In a double-blind sham-controlled within-subjects design, online stimulation was applied to the left hemispheric hand-related motor cortex of 20 healthy subjects. A dual, double-dissociation task required participants to semantically discriminate concrete (hand/foot) from abstract verb primes as well as to respond with the hand or with the foot to verb-unrelated geometric targets. Analyses were conducted with linear mixed models. Semantic priming was confirmed by faster and more accurate reactions when the response effector was congruent with the verb’s body part. Cathodal stimulation induced faster responses for hand verb primes thus indicating a somatotopical distribution of cortical activation as induced by body-related verbs. Importantly, this effect depended on performance in semantic discrimination. The current results point to verb processing being selectively modifiable by neuromodulation and at the same time to a dependence of tDCS effects on enhanced simulation. We discuss putative mechanisms operating in this reciprocal dependence of neuromodulation and motor resonance.