also did not obtain in response to just any language-related violation: there were no N400 effects to simple grammatical (morphosyntactic) violations as in “All turtles have four leg” (versus legs). Other studies confirmed that the ERPs to all sentence final words – even congruent ones – are characterized by some degree of N400 activity, and further demonstrated that N400 amplitude is highly correlated (r = .9) with an offline measure of the eliciting word’s expectancy – i.e., cloze probability, the percentage of individuals who would continue a sentence fragment with that word. This sensitivity to cloze probability obtains irrespective of contextual constraint (negating a core prediction of any view that the N400 indexes inhibition, as in Debruille 2007): N400s to the sensible and equally low cloze probability completions of strongly constraining sentences (e.g., The bill was due at the end of the hour.), and of weakly constraining sentences (He was soothed by the gentle wind.) were statistically indistinguishable, and much larger than those to high cloze probability endings (The bill was due at the end of the month.).
