With National Science Foundation support, Ms. Hart and her advisor Dr. Perfetti will conduct a year long investigation of the hypothesis that reading comprehension problems are caused by poor quality lexical representations. Much research has been undertaken to find the causes of reading comprehension problems. For example, it is well known that college age readers who have trouble comprehending what they read have smaller vocabularies, more trouble making inferences, finding main ideas, and maintaining motivation. While all of these factors are correlated with reading comprehension, it is plausible that they are manifestations of a deeper source - that of poor quality lexical representations. A single word in the mental lexicon is composed of phonological, orthographic, and semantic information. In order to support good reading comprehension, these representations must be reliable (one input connects to one lexical entry) and coherent (e.g. phonology and orthography code for the same lexical entry). When reliability and coherence break down, comprehension suffers. In the present project, Hart and Perfetti aim to describe the lexical basis of comprehension skill by equating skilled and less skilled comprehenders on reading experience. Subjects learn an artificial language under conditions where experimenters have control over subjects' experience with the language and over properties such as word frequency and homophony. At early and late stages of mastering this language, subjects receive language tests and have the electrical potentials at the scalp measured (using ERP methods) while reading the artificial language. The hypothesis being tested predicts that when tested after little experience, all subjects will behave like less-skilled comprehenders do in other experiments, and after extensive experience, all subjects will behave like skilled comprehenders.
The findings from this study are expected to clarify the nature of reading comprehension problems. Explaining comprehension difficulties at a lexical level has implications for interventions designed to improve reading comprehension.
