Processing of short vowels, long vowels, and vowel digraphs by disabled and non-disabled readers

The speed with which disabled and non-disabled readers process short vowels, long vowels, and vowel digraphs was investigated in this study, an exploration of Morrison's 1984 conceptualization of reading disability as the failure to master the complex irregular system of rules governing sound-symbol correspondence in English. 7 disabled and 7 non-disabled readers, all of average intelligence, were presented pseudoword pairs on slides and asked to identify a pronounced target word by identifying its position ("top" or "bottom"). Reaction time was measured with voice-operated relay and digital millisecond clock counter. The pseudoword pairs were formed such that each pseudoword was paired with another that was identical except for one or two vowels in the medial position. No effects of type of reader (disabled or non-disabled) and type of letters in the medial position (long vowel, short vowel, vowel digraph) on reaction time were noted. Analysis of reaction times for individual words gave significant differences. The need for an empirically supported "complexity scale" is discussed.