THE INTERACTION OF REFERENTIAL AMBIGUITY AND ARGUMENT STRUCTURE IN THE PARSING OF PREPOSITIONAL PHRASES

This research addresses the question of whether the initial interpretation of structurally ambiguous sentences (such as He dropped the book on the chair) is made purely on the basis of syntactic principles or whether semantic processes also exert an influence. Two factors, referential ambiguity (e.g., whether there is more than one referent for the book), and verb argument structure (e.g., whether the verb takes on the chair as an optional or obligatory argument) were manipulated in two experiments using a subject-paced moving-window technique. These experiments found that the need to resolve an ambiguous noun phrase referent interacted with the obligatory/optional nature of verb arguments. Discourse information affected initial syntactic assignment of the prepositional phrase, but only for verbs taking optional goal arguments. For verbs taking obligatory goal arguments, the attachment decision was independent of whether the noun phrase was referentially ambiguous. A third experiment found that prepositional phrases are not initially interpreted as modifiers if a disambiguating adjective immediately precedes the noun, clearly implicating referential ambiguity as the mechanism affecting the interpretation of the prepositional phrase. These results support a limited influence of discourse semantics on the parsing of prepositional phrases and are inconsistent with models that propose no influence of semantics on syntax and models that propose complete interaction. (C) 1994 Academic Press, Inc.