Do dyslexic and other poor readers differ in reading-related cognitive skills?

The rationale for the study was that if dyslexic and garden-variety poor readers differ in reading-related cognitive skills, there is justification for believing dyslexia to be a distinct entity. Subjects were 110 children aged 6 to 10 years, divided into groups of dyslexic poor readers varying in verbal IQ, garden-variety poor readers, and good readers. Findings suggest that there are valid grounds for believing that dyslexia is a separate entity from garden-variety poor reading, and that it is found among children at all verbal IQ levels. Poor phonological awareness and nonword reading, in relation to normal readers, were shared by dyslexic and garden-variety poor readers. Deficits unique to dyslexic poor readers were problems in both automatic visual recognition and phonological recoding of graphic stimuli. The study supports the phonological-core variable-difference model of Stanovich (1988) in that both dyslexic and garden-variety poor readers showed phonological processing deficits, but they were more extensive in dyslexics.     

Orthographic and phonological coding during visual word matching as related to reading and spelling abilities in college students

College students, scoring average to above-average on WRAT-R subscales for reading and spelling, made match/nonmatch judgments on word pairs either on the basis of phonological similarity (a rhyme match) or orthographic similarity (a visual match). Word pairs rhymed and looked similar, rhymed but looked dissimilar, or looked similar but did not rhyme. Word pairs for which a nonmatch decision had to be made, despite similarity in the irrelevant dimension, produced significantly more errors and longer response latencies. Poorer readers were less vulnerable to phonological interference when making visual discriminations, and poorer readers and spellers were more vulnerable to orthographic interference when making rhyme matches. Results showed that a deficiency in phonological coding and an over-reliance upon orthographic coding, often observed in dyslexic children, can also be seen in relatively poor readers and spellers within a normal adult population.     

Converging evidence for the concept of orthographic processing

Six different measures of orthographic processing (three different letter string choice tasks, two orthographic choice tasks, and a homophone choice task) were administered to thirty-nine children who had also been administered the word recognition subtest of the Metropolitan Achievement Test and a comprehensive battery of tasks assessing phonological processing skill (four measures of phonological sensitivity, nonword repetition, and pseudoword reading). The six orthographic tasks displayed moderate convergence – forming one reasonably coherent factor. Hierarchical regression analyses indicated that a composite measure of orthographic processing skill predicted variance in word recognition after variance accounted for by the phonological processing measures had been partialed out. A measure of print exposure predictedvariance in orthographic processing after the variance in phonologicalprocessing had been partialed out.     

Genetic etiology of spelling deficits in the Colorado and London twin studies of reading disability

The basic multiple regression model for the analysis of selected twin data (DeFries and Fulker 1985, 1988) was fitted to spelling data from 100 pairs of MZ twins and 71 pairs of same-sex DZ twins tested in the Colorado Reading Project (DeFries, Olson, Pennington and Smith 1991), and to data from 12 pairs of MZ twins and 15 pairs of same-sex DZ twins tested in the London twin study of reading disability (Stevenson, Graham, Fredman and McLoughlin 1984, 1987). Estimates of h _g ² obtained from analyses of these data suggest that about 60% of the deficit of probands is due to heritable influences in both samples. When a regression model was fitted separately to data from males and females in the combined Colorado and London samples, resulting estimates of h _g ² were 0.66±0.18 and 0.56±0.19, respectively, a nonsignificant difference. Collaborative analyses of data from additional twin studies of reading disability would facilitate more rigorous tests of hypotheses of differential genetic etiology as a function of group membership.     

Orthographic and Phonological Processes in Reading

Investigations of reading have focussed largely on two component processes, phonological processing and orthographic processing. However, a number of unresolved issues have hampered progress in the investigation of these abilities. Three such issues that formed the focus of the present study were (1) the extent to which tasks used to operationalise orthographic processing measure the same construct, (2) the extent to which tasks from a range of phonological processing domains measure the same construct, and (3) the degree to which orthographic processing tasks reflect orthographic processes independent of extraneous phonological operations, and conversely, phonological processing tasks measure phonological processes independent of orthographic processes. To address these questions, a variety of tasks used to evaluate orthographic processing (orthographic verification, homophone verification, nonlexical choice, irregular word reading, irregular word spelling), phonological processing (phoneme deletion, phonological choice, nonword reading, nonword spelling) and related domains (e.g., word identification, IQ) were administered to 177 children from Grades 3, 4 and 5. Factor analysis conducted using accuracy data revealed that orthographic processing tasks congregate along a single factor, while phonological processing tasks congregate along another, separate factor, viewed as evidence for the construct validity of orthographic processing and phonological processing, respectively. When response-time data were analysed, these same tasks did not differentiate on the basis of their orthographic and phonological demands, but rather in terms of their more general task demands. Additionally, results reveal that some phonological processing and orthographic processing tasks measure their respective construct with a greater degree of purity than do others. It is recommended that these tasks be used in future research.     

Heterogeneity in adult dyslexic readers: Relating processing skills to the speed and accuracy of oral text reading

Subgroups of Finnish dyslexic adults (N = 84)displaying, relative to each other, a distinctivecombination of accuracy and speed of oral text readingwere compared in phonological and orthographicprocessing, verbal short-term memory and readinghabits. Inaccurate phonological decoding appeared todetermine the number of errors made in text reading,while inability to utilize effectively rapid lexicalaccess of words manifested as slow text reading speed.Phonological and orthographic word recognitionprocesses were less tightly integrated among dyslexicthan normal readers. Our results indicate thatadvanced orthographic processing skills might help anumber of the dyslexic readers to compensate for theirserious phonological deficits. The subgroups alsodiffered from each other in reading habits. Arelatively fast reading speed, even with numerouserrors, appears to be more rewarding in everydayreading than a slower but more accurate readingstyle.     

Lexical- and sentence-level processes in comprehension of written sentences

Two experiments and three measures of lexical skills (word finding, rapid automatized naming, receptive vocabulary) were administered to 24 third and 24 fifth graders. Each experiment included two between-subject variables (grade and sex) and four within-subject variables (mode of sentence presentation – one word and one-sentence-at-a-time; word type – orthographic, phonological and semantic foils; position of foil in sentence – beginning, middle, and end; and sentence type – meaningful and nonsense). The experiments contrasted on reading comprehension task: receptive sentence acceptability (Experiment 1) or expressive sentence reproduction (Experiment 2). One-word-at-a-time presentation, which highlights the lexical unit, resulted in better accuracy on the expressive task that required verbatim reproduction than on the forced choice receptive task. Word finding and rapid automatized naming that require active production of phonologically-referenced name codes, but not receptive vocabulary, were correlated with measures of word recognition and reading comprehension in the experiments and on the psychometric tests. These results are consistent with Perfetti's contention that a phonologically-based name code is the heart of lexical access.     

Literacy ability and phonological processing skills amongst dyslexic and non-dyslexic speakers of Arabic

This paper investigates the relationship between phonological processing and reading ability amongst grade 4 and grade 5 Arabic speaking children in Egypt. In addition to measuring reading level, the study assessed the children’s ability to identify rhymes, delete individual phonemes from words, retain and manipulate sequences of digit names and rapidly access verbal labels. Further literacy and literacy-related tasks required children to decode novel letter strings, to distinguish similar words, to identify words within letter chains and to correctly spell dictated text. A non-verbal ability measure was also included to allow comparisons to be made between a group of poor readers with good non-verbal skills (dyslexics) with a control group of chronological-age-matched normal readers with equivalent average scores on the non-verbal task. Results indicated relationships between literacy ability, decoding and phonological processing within this cohort, as well as identifying differences between dyslexic and control groups that suggest Arabic dyslexics show signs of poor phonological skills. The study supports the view that Arabic dyslexic children have impairments in the phonological processing domain.     

Early linguistic abilities and reading development: A review and a hypothesis

This article is concerned with aspects of phonological processing and linguistic awareness that may set the stage for initial reading development. The aims are first to provide a current review of phonological processes (both underlying and metaphonological) that have been found to be associated with initial reading achievement, secondly to present a new hypothesis relating differences in the nature of phonological representations in the lexicon to the development of phonological awareness and other phonological processes. The hypothesis is concerned withdistinctness of phonological representations, i.e. the separateness of phonological representations. Phonological representations of high distinctness are distinguished from other representations by many features. The distinctness hypothesis is compared to the lexical restructuring hypothesis which suggests that lexical representations gradually become increasingly segmental between one and eight years of age. Implications of each hypothesis (emphasizing the distinctness hypothesis) for the development of language abilities and reading are presented, along with suggestions regarding future research directions.     

Does task-focused versus task-avoidance behavior matter for literacy development in an orthographically consistent language?

We examined the importance of children’s classroom activity, defined as task-focused versus task-avoidance behavior, on different literacy outcomes in an orthographically consistent language. Greek children (n = 95) were tested in kindergarten, grade 1, and grade 2 on measures of general cognitive ability, phonological awareness, RAN, and short-term memory. The teachers of the children also assessed their task-focused behavior. Nonword decoding, reading fluency, spelling, and reading comprehension measures were administered in grades 2 and 3. The results indicated that task-focused behavior accounted for unique variance in spelling and reading comprehension, even after controlling for the effects of autoregressor, non-verbal IQ, and phonological processing.     

Phonological processes as predictors of specific reading skills in children at risk for reading failure

Children at risk for reading disability were evaluated as kindergartners and again as first graders to determine (1) intercorrelations among phonological processing tasks and (2) the relationship of such tasks to word identification and word attack. With IQ controlled, there were no intercorrelations among measures of phonological awareness, phonetic recoding in working memory, and phonological recoding in lexical access. Thus, these results failed to substantiate the concept of a general phonological processing ability. Partial correlations controlling for IQ revealed no relationship between reading and phonological awareness or phonetic recoding in working memory. In contrast, lexical access measures were significantly, albeit moderately, correlated with word identification but not word attack. Word attack and word identification were predicted by different combinations of variables. These results suggest that lexical access ability is an important factor in reading acquisition and that different combinations of phonological processes may be related to different aspects of reading.This research was supported by PHS grant HD 21887 to Bowman Gray School of Medicine and by PHS Grant NS 19413 to UNC-Greensboro Subcontract to Bowman Gray School of Medicine.     

Orthographic processing is a key predictor of reading fluency in good and poor readers in a transparent orthography

We used structural equation modeling to investigate sources of individual differences in oral reading fluency in a transparent orthography, Russian. Phonological processing, orthographic processing, and rapid automatized naming were used as independent variables, each derived from a combination of two scores: phonological awareness and pseudoword repetition, spelling and orthographic choice, and rapid serial naming of letters and digits, respectively. The contribution of these to oral text-reading fluency was evaluated as a direct relationship and via two mediators, decoding accuracy and unitized reading, measured with a single-word oral reading test. The participants were “good” and “poor” readers, i.e., those with reading skills above the 90th and below the 10th percentiles (n = 1344, grades 2–6, St. Petersburg, Russia). In both groups, orthographic processing skills significantly contributed to fluency and unitized reading, but not to decoding accuracy. Phonological processing skills did not contribute directly to reading fluency in either group, while contributing to decoding accuracy and, to a lesser extent, to unitized reading. With respect to the roles of decoding accuracy and unitized reading, the results for good and poor readers diverged: in good readers, unitized reading, but not decoding accuracy, was significantly related to reading fluency. For poor readers, decoding accuracy (measured as pseudoword decoding) was related to reading fluency, but unitized reading was not. These results underscore the importance of orthographic skills for reading fluency even in an orthography with consistent phonology-to-orthography correspondences. They also point to a qualitative difference in the reading strategies of good and poor readers.     

Links among segmenting,spelling, and reading words in first and second Grades

Twenty first graders and twenty second graders were examined on skills in segmenting, reading, and spelling 50 words with regular and exceptional spelling patterns. By using the same words for each task, it was possible to assess the interrelationships among these skills on a word by word, child by child basis. A multivariate analysis of variance was conducted on difference scores among segmentation, reading, and spelling. Generally, differences favored segmentation and were maximized when final sounds were deleted and minimized when medial sounds were deleted. In addition, graphical analyses showed a greater probability of correct reading and spelling given correct segmentation than incorrect segmentation. Results were interpreted to support a computational notion of phonology as a prerequisite to reading and spelling, with a more reflective notion explaining the reciprocal relation between reading and segmentation of consonant blends and medial sounds.     

Levels of phonological representation in skilled reading and in learning to read

This paper refers to and discusses empiricalevidence supporting the general idea that bothskilled reading and learning to read capitalizeon underlying phonological representations.These representations must be specified interms of degree of abstractness, unitsrepresented and degree of conscious access tothese units. In skilled reading, pre-lexicalrepresentations, at different levels ofphonological structure, are unconsciously,mandatorily and automatically activated, inconnection with correspondent orthographicrepresentations. This process is distinct fromthe intentional and controlled phonologicaldecoding assumed by the classic dual-routemodel. Learning to read may be described as theprogression from conscious phonologicaldecoding, in which phoneme awareness plays acritical role, to the unconscious mapping oforthographic and phonological segments.Phonological dyslexia is related to someanomaly in speech perception capacities, makingit difficult both to develop efficientconscious segmentation abilities andgrapho-phonological decoding. It is suggestedthat this conscious speech segmentation deficitis caused by a lack of appropriate segmentationat the unconscious, perceptual level.     

Lexical and nonlexical processes in the skilled reading and spelling of Persian

The objective of the present study was to examine the contribution of lexical and nonlexical processes to skilled reading and spelling in Persian. Persian is a mixed orthography that allows one to study within one language characteristics typically found in shallow orthographies as well as those found in deeper orthographies. 61 senior high-school students (mean age = 17; 8, SD = 4 months) attending schools in Iran were tested on reading and spelling of words and nonwords. The word stimuli differed in terms of reading transparency (transparent when all phonemes have corresponding letters vs. opaque when short vowels were not marked with a letter) and spelling polygraphy (nonpolygraphic phonemes vs. polygraphic phonemes). The nonwords were transparent and nonpolygraphic. The reading results showed that both transparent and opaque words were read faster than nonwords, and that transparent words were read faster than opaque words. Moreover, both transparent and opaque words were affected by word frequency. These findings suggest that skilled readers of Persian relied on lexical processes to read words. In contrast, the spelling results failed to show a word-advantage effect suggesting that skilled spellers of Persian rely on nonlexical processes to spell words. Moreover, orthographic complexity also affected spelling. Specifically, nonpolygraphic words were spelled faster than polygraphic words for both transparent and opaque words. Taken together, the findings showed that skilled reading and spelling in Persian rely on different underlying processes.     

The use of phonological, orthographic, and contextual information during reading: a comparison of adults who are learning to read and skilled adult readers

The purpose of this study was to assess the role that phonological, orthographic, and contextual sources of information play in a group of adults who were learning to read compared to adult skilled readers. Participants read short paragraphs that contained a correct homophone, an incorrect homophone, or a spelling control. Target words were orthographically similar or dissimilar, and they appeared in context that predicted the target or was neutral with respect to the target. The pattern of data obtained for skilled readers was consistent with past work (Rayner et al., Journal of Experimental Psychology: Learning, Memory and Cognition 24(2), 476–497, 1998). Skilled readers showed no reading time differences between the correct homophone and the incorrect homophone, as long as the two were orthographically similar, but reading times on these words were faster than the spelling control condition. The pattern of data for the adults who were learning to read was different. These readers were actually better at noticing that an incorrect version of the homophone was present. Importantly, we did find consistent significant differences between the incorrect homophone condition and the spelling control condition. This suggests the adults who were learning to read use phonological codes during word recognition, but they do so less efficiently than skilled readers.     

Longitudinal twin study of early literacy development: Preschool through Grade 1

Grade 1 literacy skills of twin children in Australia (New South Wales) and the United States (Colorado) were explored in a genetically sensitive design (N = 319 pairs). Analyses indicated strong genetic influence on word and nonword identification, reading comprehension, and spelling. Rapid naming showed more modest, though reliable, genetic influence. Phonological awareness was subject to high nonshared environment and no reliable genetic effects, and individual measures of memory and learning were also less affected by genes than nonshared environment. Multivariate analyses showed that the same genes affected word identification, reading comprehension, and spelling. Country comparisons indicated that the patterns of genetic influence on reading and spelling in Grade 1 were similar, though for the U.S. but not the Australian children new genes came on stream in the move from kindergarten to Grade 1. We suggest that this is because the more intensive kindergarten literacy curriculum in New South Wales compared with Colorado, consistent with the mean differences between the two countries, means that more of the genes are “online” sooner in Australia because of accelerated overall reading development.     

Phonological skills and comprehension failure: A test of the phonological processing deficit hypothesis

Shankweiler and colleagues argue that text comprehensionproblems in young children arise from phonological processingdifficulties. Their work has focused on children with poor wordreading ability. We investigated this hypothesis for children whoexperience comprehension difficulties in the presence of age-appropriate word reading skills. We found that good and poorcomprehenders performed comparably on various measures ofphonological processing and differed on a task that made greaterdemands on working memory, Bradley and Bryant's odd-word-outtask. In a final study, hierarchical regression analyses supportedthis distinction: the odd-word-out task was a strong predictor ofreading comprehension performance even after IQ, vocabulary and single word reading had been controlled for, but a lessmemory-dependent phonological task was not. These studiessupport previous work which indicates that poor comprehenders'problems arise from higher-level processing difficulties.     

Contribution of phonological,morphological and orthographic awareness to English word spelling: A comparison of EL1 and EFL models

The purpose of the present study was to examine the contribution of metalinguistic skills—as measured through orthographic awareness, phonological awareness, and morphological awareness—to the English spelling ability of Grade 8 Chinese students who study English as a foreign language (EFL group) and of third graders in the U.S. whose first language is English (EL1 group). The two groups were initially matched through calculating the Flesch-Kincaid reading level of Chinese EFL students' textbooks and then through propensity score matching, taking into consideration various predictors. Using multiple regression and dominance analysis, we compared the models of metalinguistic awareness that predict English word spelling between the two groups. We found that orthographic awareness and morphological awareness were uniquely related to spelling for the EL1 group, whereas morphological awareness, orthographic awareness and phonological awareness were uniquely related to spelling for the EFL group, after accounting for the effect of vocabulary. Further analysis of relative importance of the predictors showed that orthographic choice was the dominant predictor for the EL1 group and inflectional morpheme production was the dominant predictor for the EFL group. The importance of metalinguistic awareness in acquiring English spelling in both EL1 and EFL groups is discussed.