Differential effects of saliency: an event-related brain potential study

We present event-related brain potential evidence from language comprehension that the N400-modulation during noun-phrase integration is a function of the type of referential dependency that is established (identity versus inference) and the saliency (in the following understood as the sum of factors that influence the degree of accessibility of an entity in the mental model) of the information unit that serves as an anchor for the dependency. Identity relations revealed a reduced N400 compared to inferential relations, confirming previous findings. More importantly, the investigation provides novel findings concerning the effect of saliency on noun-phrase integration: identity relations did not reveal a difference in the N400 as a function of the saliency manipulation. In contrast, inferential relations showed a more pronounced N400 with less salient anchors compared to inferential relations that involved a highly salient anchor. Moreover, no difference in N400-amplitude obtained between less salient inference-based entities and new information units. These data suggest that inferential processes are blocked in the absence of a highly accessible anchor. The findings generally indicate that the language system is not only sensitive to the kind of dependency that is established, but also to the saliency of the entity that serves as anchor for the dependency. The data further demonstrate that the processing system is responsive to semantic- and discourse-level information during the interpretation of noun-phrases.