Although the N400 is broadly sensitive to factors related to semantic fit, some surprises have been encountered, especially the finding that thematic role (verb argument) violations, which a priori were thought to be semantic in nature and certainly have strong semantic implications, did not necessarily modulate N400 amplitudes (reviewed in Kuperberg 2007). For example, N400s were not different to “eat” in “For breakfast the boys would only eat…” than in the thematically incongruent “For breakfast the eggs would only eat…” Instead, this comparison yielded a P600-like positivity. Importantly, such findings, like those for negation, constraint, and related anomalies, serve to emphasize that the N400 is not simply an index of semantic plausibility. Instead, it seems clear that plausibility judgments are some function of a number of processes that differ in the time course of their availability -- and are usually evaluated as a non-speeded, end-state response. In contrast, the N400 occupies a temporally delimited place within an incremental system (see discussion in Federmeier & Laszlo 2009). Thus, in some cases (e.g., negation in the absence of pragmatic licensing), information that
