Processing Presupposed Content Florian Schwarz University of Massachusetts Amherst December 2006 Abstract This paper presents three experimental studies investigating the processing of presupposed content. The first two experiments employ the German additive particle auch (too ), and the third uses Eng- lish also. In experiment 1, participants were given a questionnaire containing bi-clausal, ambiguous sentences with auch in the second clause. The presupposition introduced by auch was only satisfied on one of the two readings of the sentence, and this reading corresponded to a syntactically dispreferred parse of the sentence. The prospect of having the auch -presupposition satisfied made participants choose this syntactically dispreferred reading more frequently than in a con- trol condition. Experiment 2 used the self-paced-reading paradigm and compared the reading times on clauses containing auch, which differed in whether the presupposition of auch was satisfied or not. Participants read the clause more slowly when the presupposition was not satisfied. Experiment 3 followed up a number of issues that arose from experiment 2 and confirmed the results found there. Further- more, it made an attempt at determining the level of representation relevant for the processes under investigation. It is argued that these studies show that presuppositions play an important role in online sen- tence comprehension and affect the choice of syntactic analysis. Some theoretical implications of these findings for semantic theory and dy- namic accounts of presuppositions as well as for theories of semantic processing are discussed. 1