Human brain potentials to reading syntactic errors in sentences of different complexity

In order to determine if an event-related brain potential (ERP) effect described for syntactic violations (P600/SPS) varies with the amount of reprocessing entailed by a violation, number incongruencies were presented either within simple declarative or within subordinate clauses. ERPs were recorded while 12 German subjects read the stimulus materials presented word by word on a video monitor. The ERPs showed a P600/SPS effect for all sentence types, which was smallest in amplitude and earliest in latency for simple declarative sentences. This effect therefore qualifies as a metric for the amount and timing of syntactic reprocessing entailed by a syntactic error. In addition, a late frontal negativity (1000–1400 ms range) was found for the simple declarative sentences.