In this thesis we shall investigate the kinds of information which the Human Sentence Processing Mechanism employs during the resolution of local syntactic ambiguity in written texts. The thesis is in three parts. In Part I we consider some current models of syntactic ambiguity resolution. On the one hand, we consider the structural approaches, in which the processor considers only syntactic information when choosing between alternatives. On the other, we consider the interactive approaches, in which different kinds of information are brought to bear during the resolution process. In Part II, we describe a number of experiments which contrast the predictions of these two approaches. In particular, we investigate the processing of sentences which are locally ambiguous between a simple noun phrase analysis and a complex noun phrase analysis. Frazier (1979) predicts that the simple noun phrase analysis is chosen because it utilizes fewest phrasal nodes in its associated phrase marker. Crain and Steedman (1985), however, predict that the interpretation of the noun phrase is determined by referential factors, such as whether or not a unique referent can be identified for the noun phrase. The results support Crain and Steedman's interactive hypothesis. In Part III, we consider some theoretical issues concerning the timing of the processor's decisions. Crain and Steedman's original model is modified in the light of such considerations. We explore the implications of the modification for the status of syntax and semantics within our model of sentence comprehension. In the final chapter, we attempt to explain the existence of parsing preferences in sentences which are presented in isolation, and for which no explicit contextual information has been provided. We conclude that contextual considerations, such as the distinction between what is and what is not already known to the hearer, are of fundamental importance during the resolution of local syntactic ambiguity by the Human Sentence Processing Mechanism.

The primary focus of this thesis was to find out what makes workable topic sentences different from inadequate ones. A group of topic sentences was collected from the author's eight grade students and reviewed.