Syntactic presupposition in sentence comprehension

Two experiments investigated the role of syntactic presupposition in sentence comprehension. In Experiment I subjects verified cleft, pseudocleft and factive complement sentences with respect to preceding context paragraphs, which contradicted either the assertion or the presupposition of the target sentence. Subjects took significantly longer to verify sentences with false presuppositions than sentences with false assertions. In Experiment II subjects verified cleft and pseudocleft sentences with respect to subsequently presented pictures. Once again, verification times for sentences with false presuppositions were significantly longer than verification times for sentences with false assertions. It was argued that these findings are more adequately explained by a “structural” hypothesis, than in terms of strategies designed to locate given and new information.