Processing of Derived Forms in High- Functioning Dyslexics S. Hélène Deacon 1 , Rauno Parrila 2 , & John R. Kirby 3 1 Dalhousie University, Halifax, Nova Scotia, Canada 2 University of Alberta, Edmonton, Alberta, Canada & 3 Queen’s University at Kingston, Ontario, Canada We report on an experiment designed to evaluate processing of derived forms in high-functioning dyslexics, defined as university students with a history of reading difficulties who have age-appropriate reading comprehension skills. We compared high-functioning dyslexics with a group of normal adult readers in their performance on a lexical deci- sion task with derived items (such as cloudy and ably) and pseudo- derived items (such as belly and gravy). Some items contained an orthographic change (such as able-ably and gravy) and others did not (such as cloud - cloudy). The results indicated that although con- trol participants’ response times varied systematically as a function of morphological complexity, those of high-functioning dyslexics did not. Further, there was some evidence of a relationship between deriva- tional processing and reading. It seems that high-functioning dyslex- ics have persistent difficulties in processing one particular aspect of morphology; that of derived forms. Key Words: Derivational processing, high-functioning dyslexics, morphology, orthographic complexity, reading difficulties A long line of research has demonstrated that phonological awareness is a key and causal factor in literacy development Annals of Dyslexia, Vol. 56, No. 1, 2006 Copyright ©2006 by The International Dyslexia Association ® ISSN 0736-9387 103