Processing references in context: when the polar bear does not meet a polar bear.

Discourse understanding is hampered when missing or conflicting context information is given. In four experiments, we investigated what happens (a) when the definite determiner "the," which presupposes existence and uniqueness, does not find a unique referent in the context or (b) when the appropriate use of the indefinite determiner is violated by the presence of a unique referent (Experiment 1 and Experiment 2). To focus on the time-course of processing the uniqueness presupposition of the definite determiner, we embedded the determiner in different sentence structures and varied the context (Experiment 3 and Experiment 4).

Context-dependent impact of presuppositions on early magnetic brain responses during speech perception.

Discourse structure enables us to generate expectations based upon linguistic material that has already been introduced. The present magnetoencephalography (MEG) study addresses auditory perception of test sentences in which discourse coherence was manipulated by using presuppositions (PSP) that either correspond or fail to correspond to items in preceding context sentences with respect to uniqueness and existence. Context violations yielded delayed auditory M50 and enhanced auditory M200 cross-correlation responses to syllable onsets within an analysis window of 1.