The interpretation of reading difficulties can be wrapped up by presenting examples of studies that integrate Luria’s notion, as we discussed earlier, with contemporary views. Here is a scientific report, written in the style of an article in an academic journal. So, I hope that psychologists and other academics will find it worth reading. Is it of interest to teachers? For every one of them! Why not?
The inability to engage in phonological coding has been suggested as the major cause of reading disability for children (Stanovich, 1988; Torgesen et al, 1994). Researchers generally agree that phonological processing plays an important role in early reading. One of the most frequently cited articles in the field (Torgesen et al, 1994) argues that phonological processing abilities are causally related to normal acquisition of reading skills. Support for this claim can also be found in the relationship between pre-readers’ phonological processing scores and their reading development after one to three years (for example, Bradley and Bryant, 1985). A review by Share and Stanovich (1995) concluded that there is virtually unassailable evidence that poor readers, as a group, are impaired in a very wide range of basic cognitive tasks in the phonological domain (1995: 9).
The belief that phonological coding is a “bottleneck” process deficit in dyslexia has been reiterated by Frith (1999). She reflects the emerging consensus that dyslexia is a condition marked by a phonological deficit. She suggests that dyslexia should be defined in conjunction with three levels of manifestation—-biological, cognitive, and behavioral. Each of these levels interacts with the cultural environment. According to her, dyslexia is a neurodevelopmental disorder with a biological origin. Brain activation studies, in which Frith is a coauthor, have recently shown that dyslexics have significantly lower levels of activation, localized in parts of the temporal-occipital region (Paulesu et al., 2001).
A distinction has been made between the true dyslexic, with specific cognitive difficulties, and the so-called garden-variety poor reader (Stanovich, 1988). The general poor reader should not be included within the broad category of dyslexics, as poor performance in reading does not necessarily imply a neurodevelopmental disorder. Poor reading can result from a variety of reasons, such as poor instruction, lack of motivation, health and emotional problems, and/or lack of cultural literacy, as well as environmental disadvantages, such as inadequate and low general intelligence. Some of these deficiencies can be removed through tutoring and remedial reading programs.
With regard to a strict application of the category dyslexia, there is an apparent heterogeneity. Surface and deep dyslexia, delayed speed in word reading, are different from the inaccurate reading of words and pseudo-words (phonological dyslexia), and have been discussed in the literature. A recent theoretical review, proposing how one transforms the printed word to speech (Colt heart el al., 2001), discusses some of these different kinds of dyslexia and attempts to integrate them by using the familiar concepts in reading—orthographic analysis, grapheme-phoneme correspondence, semantic coding, and phonological output lexicon.
But the question is—can we assume that both word-reading difficulty and phonological coding deficits among children can be related to fundamental problems in cognitive processing, as measured by tasks that do not require reading? Or, is reading perhaps a module separate from general cognitive processing? The literature on reading is vast and varied, and, therefore, we will answer these concerns within the context of PASS theory.
Children with specific reading difficulties in decoding written words (in English) are distinguished from generally poor readers. Specific deficiencies are detected by a limited number of tests. These include immediate sequential recall of word or digit series (order rather than item memory), rapid naming of letters, simple familiar words, familiar colors and objects, speed repetition of words and pseudo-words (speech rate), and also phonological awareness tests (Kirby, Booth and Das, 1996). Frith (1985) depicts these as the watershed measures that characterize individuals with specific reading disabilities or dyslexia.
Does the source of dyslexia lie in cognitive skills that are found only in reading-related tasks, in tasks related to phonology, or in a more fundamental process identifiable in nonreading tasks as well (Das, 1995a)? The latter are sometimes referred to as distal processes, in contrast to the former, which are referred to as proximal processes. Torgesen et al. (1987) identified three subprocesses of the proximal kind—knowledge of letters and letter combinations, a spoken lexicon that is necessary for recognizing the words after they are spoken, and phonetic recoding in working memory that is helpful in maintaining the spoken word in working memory.
Coltheart et al. (2001) explain the visual recognition of words and pseudo-words, but do not concern themselves with speech inputs and the phonological recoding of speech. How does a spoken word get analyzed and produce a speech response, as when we are asked to repeat a word we have just heard? Dyslexics and poor readers are sometimes unable to repeat an unfamiliar or a pseudo-word, perhaps because that too involves a phonological conversion (Patterson and Shewell’s model cited in Coltheart et al., 2001).
Phonological processing, then, appears to be required in both speech repetition and in reading aloud from print. Poor reading and its restricted variation, dyslexia, are characterized, essentially, by a deficit in phonological recoding. It is reasonable to regard both as speech-related deficits. “The processing of speech sounds has been targeted as the critical link between spoken and written languages,” writes Frith (1999: 202), supporting the early research of Bradley and Bryant (1985). She continues, “There is robust evidence that difficulties in the acquisition of reading are related to difficulties in the ability to segment the stream of speech” (ibid.).
In view of the preceding discussion, there are strong grounds for believing that the distal processes that influence reading and speech repetition must have a common requirement for phonological recoding. In our view, the distal processes may include working memory and knowledge base, but, additionally, one or all of the four PASS processes. These contribute to the acquisition of phonological and orthographic skills (important for spelling) as well as to strategies for appropriate application (Das, 1995a; Das, Parrila and Papadopoulus, 2000).