ABSTRACT
The quest to define subtypes of poor readers has been an enticing one for the field of reading. There is enormous face validity to the idea that reading-disabled individuals differ among themselves in the way that they have become poor readers and in the cognitive underpinnings of their disability. Yet the field has made very little progress toward defining separable groups of disabled readers—that is, subgroups who are behav-iorally, genetically, and physiologically different from each other. However, the field has made what might be termed “negative progress.” We are here referring to the early history of the field in which the definition of reading disability or dyslexia was tied to the notion of aptitude/achievement discrepancy (Ceci, 1986; Reynolds, 1985; Shepard, 1980; Siegel, 1989; Stanovich, 1991, 1993b, 1994). From the very beginning of research on reading disability, it was assumed that poor readers who were of high intelligence formed a group who were cognitively and neurologically different. Investigators who pioneered the study of the condition then known as congenital word-blindness (e.g., Hinshelwood, 1917) were at pains to differentiate reading-disabled children with high intelligence from other poor readers.
