With National Science Foundation support, Dr. Brian McElree will conduct three years of psycholinguistic research on people's interpretation of simple and complex expressions. Language comprehension requires operations ranging from the identification of individual words to the construction of a suitable interpretation for a complete text or utterance. Recent formal analyses suggest that complex operations are needed to derive a contextually suitable interpretation of even common and seemingly simple expressions. These operations appear to modify default interpretations of individual constituents, and they often generate semantic content that is not explicitly represented in the sentence or discourse. This project seeks to identify the processes and knowledge structures used in language comprehension, and to determine whether some compositional processes draw on local lexical properties rather than world knowledge. Experiments will dissociate simple and enriched forms of composition and so identify the properties that distinguish these different forms of composition. On-line measures of sentence processing (eye-movement patterns, self-paced reading times, and time-course functions derived from the speed-accuracy tradeoff procedure) will contrast expressions hypothesized both to depend on different types of information and to engage different kinds of compositional operations. The experiments will examine how local (phrase-internal) and global constraints affect composition, and whether there are aspects of the compositional process that operate in a context-insensitive manner. This project will advance our understanding of the critical interface between lexical and syntactic processing on one hand and discourse and text comprehension on the other. The research should also have implications for formal linguistic theory, as well as for the development of efficient natural language understanding systems. Moreover, as some aphasics show selective deficits in understanding expressions requiring enriched composition, this research may also aid in the characterization of particular language disorders and illuminate the neural structures serving language processing. The project will also provide valuable research experience for undergraduates and advanced training for postdoctoral students.
