New evidence for morphological errors in deep dyslexia

Abstract

Morphological errors in reading aloud (e.g., sexist -> sexy) are a central feature of the syniptom-complex known as deep dyslexia, and have historically been viewed its evidence that representations at some level of the reading system are morphologically structured. However, it has been proposed (Funnell, 1987) that morphological errors in deep dyslexia are not morphological in nature but are actually a type of visual error that arises when a target word that cannot be read aloud (by virtue of its low imageability and/or frequency) is modified to form it visually similar word that can be read aloud (by virtue of its higher imageability and/or frequency). In the work reported here, the deep dyslexic patient DE read aloud lists of genuinely suffixed words (e.g., killer), pseudosuffixed words (e.g., corner), and words with non-morphological embeddings (e.g., cornea). Results revealed that the morphological status of a word had a significant influence oil the production of stein errors (i.e., errors that include the stein or pseudostem of the target): genuinely suffixed words yielded more stem errors than pseudosuffixed words or words with non-morphological embeddings. This effect of morphological status could not be attributed to the relative levels of target and stem imageability and/or frequency. We argue that this pattern of data indicates that apparent morphological errors in deep dyslexic reading are genuinely morphological, and discuss the implications of these errors for theories of deep dyslexia. (c) 2005 Elsevier Inc. All rights reserved.