Evaluating current deficit theories of poor reading: role of phonological processing, naming speed, balance automaticity, rapid verbal perception and working memory

To clarify the nature of cognitive deficits experienced by poor readers, 9-10-yr.-old poor readers were matched against 9 chronological age and 9 younger reading age-matched controls screened and selected from regular classrooms. Poor readers performed significantly more poorly than chronological age-matched peers on digit naming speed, spoonerisms, and nonsense word reading. Poor readers were also significantly poorer than reading age-matched controls on nonword reading but were significantly better than reading age-matched controls on postural stability. Analyses of effect sizes were consistent with these findings, showing strong effects for digit naming speed, spoonerisms, and nonword reading. However, effect size analysis also suggested that poor readers experienced moderate difficulties with balance automatisation but did not show verbal speech perception deficits relative to either control     

Picture Naming Deficits in Developmental Dyslexia: The Phonological Representations Hypothesis

The picture and word naming performance of developmental dyslexics was compared to the picture and word naming performance of non-dyslexic (“garden variety”) poor readers, reading age, and chronological age-matched controls. The stimulus list used for both tasks was systematically manipulated for word length and word frequency. In order to examine picture naming errors in more depth, an object name recognition test assessed each subject's vocabulary knowledge of those names which they were unable to spontaneously label in the picture naming task. Findings indicated that the dyslexic and the garden variety poor readers exhibited a picture naming deficit relative to both chronological and reading age-matched controls. Findings also indicated that both groups of impaired readers obtained superior scores in the word naming task than in the picture naming task, while both groups of controls showed no difference in performance across tasks. The dyslexics' picture naming errors, but not those of the garden variety poor readers, were particularly marked on polysyllabic and/or low frequency words, indicating a possible phonological basis to the picture naming deficit of the dyslexic children. These children also recognized significantly more unnamed target words than all comparison groups, suggesting a particular difficulty inretrievingthe phonological codes of known picture names rather than a vocabulary deficit. Results are discussed in terms of dyslexics' difficulty in encoding full segmental phonological representations of names in long-term memory and/or in processing these representations in order to generate required names on demand.     

Word length,phonemic, and visual similarity effects in poor and normal readers

Serial order recall for visually and auditorily presented stimuli was examined in a group of 12-year-old poor readers and 7-year-old reading-age controls. With pictorial presentation, the poor readers showed a visual similarity effect, no word length effect, and a smaller phonemic similarity effect than that of controls. However, with visual presentation of printed words and with auditory presentation, poor readers showed word length and phonemic similarity effects of similar magnitude to that of controls. It is concluded that poor readers rely on visual information in tasks where the presented images are highly codable, and where verbal recoding is not obligatory, but that they will make use of phonological coding when the stimuli are not as easily codable visually in memory.     

The use of phonological information by good and poor readers in memory and reading tasks

There has been a recent debate about the utilization of phonological information by poor readers in both working memory and reading tasks. The purpose of the first experiment in this study was to examine whether the absence of phonological similarity effects in working memory reported in previous studies was due to inappropriate levels of task difficulty. Poor readers and their reading age controls were found to show a normal effect when the memory task was at an appropriate level of difficulty, but no effect when a large number of items had to be recalled. However, in a recognition memory task, the poor readers chose orthographically similar pairs, whereas the reading-age and chronological age controls chose phonologically similar pairs. The purpose of a final experiment was to determine whether or not the good and poor readers could be differentiated in terms of their reading strategies; both groups showed regularity effects in a naming task and pseudohomophone effects in a lexical decision task. However, although poor readers could read three-letter nonwords as well as their controls, they were significantly impaired in reading more complex one-syllable nonwords. It was concluded that poor readers may have a phonological dysfunction in some aspects of reading that is unrelated to whether or not they show phonological similarity effects in working memory. Impaired segmentation skills may underly their difficulties in both reading and nonreading tasks.     

Visual rapid naming and phonological abilities: different subtypes in dyslexic children

One implication of the double-deficit hypothesis for dyslexia is that there should be subtypes of dyslexic readers that exhibit rapid naming deficits with or without concomitant phonological processing problems. In the current study, we investigated the validity of this hypothesis for Portuguese orthography, which is more consistent than English orthography, by exploring different cognitive profiles in a sample of dyslexic children. In particular, we were interested in identifying readers characterized by a pure rapid automatized naming deficit. We also examined whether rapid naming and phonological awareness independently account for individual differences in reading performance. We characterized the performance of dyslexic readers and a control group of normal readers matched for age on reading, visual rapid naming and phonological processing tasks. Our results suggest that there is a subgroup of dyslexic readers with intact phonological processing capacity (in terms of both accuracy and speed measures) but poor rapid naming skills. We also provide evidence for an independent association between rapid naming and reading competence in the dyslexic sample, when the effect of phonological skills was controlled. Altogether, the results are more consistent with the view that rapid naming problems in dyslexia represent a second core deficit rather than an exclusive phonological explanation for the rapid naming deficits. Furthermore, additional non-phonological processes, which subserve rapid naming performance, contribute independently to reading development.     

The effect of word length on lexical decision in dyslexic and normal reading children

In the present study, the effect of word length on lexical decision in dyslexic and normal reading children was investigated. Dyslexics of 10-years old, chronological age controls, and reading age controls read words and pseudowords consisting of 3 to 6 letters in a lexical decision task. Length effects were much stronger in dyslexics and reading age controls than in chronological age controls. These results support the contention that dyslexics continue to rely on a predominantly sub-lexical reading procedure, whereas for normal readers the contribution of a lexical reading procedure increases. The relevance of the findings for current computational models of reading is discussed.     

Default spacing is the optimal spacing for word reading

Increased interletter spacing is thought to reduce crowding effects and to enhance fluent reading. Several studies have shown beneficial effects of increased interletter spacing on reading speed and accuracy, especially in poor readers. Therefore, increased interletter spacing appears to be a relatively easy way to enhance reading performance. However, in adult readers reading speed was shown to be impeded with increased interletter spacing. Thus, findings on interletter spacing are still inconclusive. In the current study we examined the effect of a range of interletter spacings (?0.5, default, 0.5, 1, 1.5, 2) on naming fluency of monosyllabic and bisyllabic words in beginning (Grade 2) and more advanced (Grade 4) readers. Additionally we tested the effects of spacing in a subsample of poor readers. In contrast to previous findings, neither beginning nor advanced readers benefited from an increase in interletter spacing. However, they did show reduced reading fluency when letter spacing was smaller than the default spacing, which may be indicative of a crowding effect. Poor readers showed a similar pattern. We conclude that an increase in interletter spacing has no effect on word naming fluency.     

Naming speed deficits in reading disability: multiple measures of a singular process

Speed of word identification is important in the theories of reading proposed by La Berge and Samuels (1974) and Perfetti (1985), and is substantially correlated with reading skill. However, there is controversy about whether disabled readers have a speed deficit that is restricted to the identification of printed words, or if instead, they have a more general speed deficit in retrieving names of even single digits. To investigate this issue, poor and average readers (N = 43) in grade 2 were assessed on several indices of speed of digit and letter naming, using both continuous-list and discrete-trial methodologies. MANCOVA indicated clear effects of reader group on discrete-trial latencies, as well as an interaction between reader group and the speed with which to-be-named items were presented. A series of hierarchical regression analyses explored the amount of shared variance between various measures of digit naming speed and five indices of reading skill. Latency for word identification shares considerable variance with latency for digit naming, and, in general, accounts for the shared variance of naming speed and several other measures of reading skill. Naming speed contributed variance in reading skill. Naming speed contributed variance in reading skill independently of measures of phonological awareness.     

Toward a comprehensive view of the skills involved in word reading in Grades 4, 6, and 8

Research to date has proposed four main variables involved in reading development: phonological awareness, naming speed, orthographic knowledge, and morphological awareness. Although each of these variables has been examined in the context of one or two of the other variables, this study examines all four factors together to assess their unique contribution to reading. A sample of children in Grades 4, 6, and 8 (ages 10, 12, and 14 years) completed a battery of tests that included at least one measure of each of the four variables and two measures of reading accuracy. Phonological awareness, orthographic knowledge, and morphological awareness each contributed uniquely to real word and pseudoword reading beyond the other variables, whereas naming speed did not survive these stringent controls. The results support the sustained importance of these three skills in reading by older readers.     

Word identification in isolation and in context by college dyslexic students

College dyslexic students (DYS) were compared to chronological age (CA)-matched and to reading age (RA)-matched control groups on tasks assessing naming of words and nonwords, regular and irregular words, and the use of context in word identification. The DYS group had the slowest naming latency for words in all tasks. In addition, they had extreme difficulty in naming nonwords, which in terms of the dual-route model for word recognition indicates impairment in the indirect route to the lexicon. However, they displayed a regularity effect in reading regular and irregular words and thus apparently utilized the indirect route in reading words. Correlational data supported the conclusion that the data are in conflict with the traditional dual-route model, and an alternative conceptualization is suggested. The use of context is discussed in terms of the interactive-compensatory model (Stanovich, 1980) and findings were generally supportive of the model. The DYS subjects of the present study appeared to be different from the RA controls and their performance did not support a developmental-lag model for explaining their reading problems.     

Dyslexia, dysnomia, and lexical retrieval: a longitudinal investigation

Results from a 3-year longitudinal investigation of confrontation naming in 98 children (75 average readers, 14 severely impaired readers, 9 bilingual readers) indicate: kindergarten performance on confrontation naming predicts Grade 2 reading performance, particularly reading comprehension; confrontation naming differentiates average from severely impaired readers; and lexical retrieval, not vocabulary knowledge, is the major source of difference between reading groups. Findings on lexical retrieval are integrated with research on naming access speed. The implications of these results for specification of dyslexia subgroups are discussed.     

USING A DICTIONARY: ITS INFLUENCE ON CHILDREN'S READING,SPELLING, AND PHONOLOGY

The developing use of a dictionary has the potential to provide self-teaching opportunities to improve reading, spelling and general phonological skills. Children's dictionary use was examined in two studies to find out patterns of use, skill and frequency of use and the relationships between these and reading, spelling and phonological development. In the first study 39 poor readers were compared with two groups of average readers, one consisting of 39 younger average readers of the same reading age and the other group of 31 average readers matched by age. In the second study 241 children (7–11 years) were divided on the basis of being above or below 9 years in age to examine developmental change. In both studies levels of non-verbal IQ were controlled between groups. Tests of reading vocabulary, spelling, non-word reading and speed and accuracy in looking up words in a dictionary were given. Examining dictionary skills in poor readers showed that they were significantly slower and less accurate in looking up words in a dictionary than their age peers who were average readers. Patterns of dictionary use varied with age with younger readers being three times more likely to give first preference to using a dictionary to look up spellings, whereas older reader expressed a preference that was much more evenly divided between checking spelling and looking up for meaning. Poor readers were much closer to their age peers in pattern of use. Self-rated frequency of dictionary use correlated significantly with spelling skill only in the younger readers. Persuading younger children to use a dictionary more could develop their spelling skills, possibly by encouraging them to be more proactive.     

Correlates of Canadian native children's reading performance: From cognitive styles to cognitive processes

Individual differences in reading and cognitive processing among a sample of generally poor readers were studied in order to answer two major questions: Do they have a specific cognitive style that favors global-simultaneous strategies and a weak sequential strategy? If they do not have a distinct cognitive style or strategy, but are merely poor in using sequential (Successive) strategies, then, would the same processes that influence reading performance in the general population determine their performance as well? A sample of 84 Canadian First Nations (FN) children were assessed in word and pseudoword reading, rapid naming speed, and ability to process information using the Planning, Attention, Successive, and Simultaneous (PASS) theory of intelligence. Results confirmed that this sample of children did not exhibit a specific cognitive style. Rather, there was evidence of a weakness in Successive processing only in the subgroup of poor readers. The importance of understanding the role of Successive processing and rapid naming speed relative to reading is further discussed.     

Not all phonological awareness deficits are created equal: evidence from a comparison between children with Otitis Media and poor readers

Children with reading difficulties and children with a history of repeated ear infections (Otitis Media, OM) are both thought to have phonological impairments, but for quite different reasons. This paper examines the profile of phonological and morphological awareness in poor readers and children with OM. Thirty‐three poor readers were compared to individually matched chronological age and reading age controls. Their phonological awareness and morphological awareness skills were consistently at the level of reading age matched controls. Unexpectedly, a significant minority (25%) of the poor readers had some degree of undiagnosed mild or very mild hearing loss. Twenty‐nine children with a history of OM and their matched controls completed the same battery of tasks. They showed relatively small delays in their literacy and showed no impairment in morphological awareness but had phonological awareness scores below the level of reading age matched controls. Further analysis suggested that this weakness in phonological awareness was carried by a specific weakness in segmenting and blending phonemes, with relatively good performance on phoneme manipulation tasks. Results suggest that children with OM show a circumscribed deficit in phoneme segmentation and blending, while poor readers show a broader metalinguistic impairment which is more closely associated with reading difficulties.     

Poor readers’ use of orthographic information in learning to read new words: A visual bias or a phonological deficit?

In this study, we examined the ability of 11-year-old poor readers and reading age controls to learn new print vocabulary. It was found that the poor readers were slower than the controls to learn to read a set of nonwords accurately but that, when asked to pick out the nonwords in a visual recognition memory task, they reached criterion much more quickly than did the controls. However, when the groups were compared on auditory recall of the items being learned, the poor readers were at a disadvantage. Thus, the poor readers developed a visual store for the nonwords more quickly than did the controls but were slower to establish phonological representations for the nonwords. It was concluded that the poor readers were slower to establish a form of sight word reading that was well underpinned in memory by connections between the letters in the spelling and the phonemes in the pronunciation, suggesting that they had a greater reliance on an orthographic-semantic pathway in word recognition than did the controls.     

Onsets and rimes in a phonologically transparent orthography: differences between good and poor beginning readers of Dutch.

This study investigates whether beginning readers of Dutch develop onset-rime units when these units are emphasized in their reading method, even when the orthography is transparent at the grapheme-phoneme level. The speed of naming intact pseudowords (wot) was compared with the speed of naming pseudowords with an onset-rime (w ot) or body-coda (wo t) segmentation. Whereas body-coda items consistently slowed down naming for both good and poor readers, the onset-rime effect covaried with reading skill: it changed from inhibitory for good readers to facilitatory for poor readers. Two alternative explanations are proposed.     

How strongly do word reading times and lexical decision times correlate? Combining data from eye movement corpora and megastudies

We assess the amount of shared variance between three measures of visual word recognition latencies: eye movement latencies, lexical decision times, and naming times. After partialling out the effects of word frequency and word length, two well-documented predictors of word recognition latencies, we see that 7–44% of the variance is uniquely shared between lexical decision times and naming times, depending on the frequency range of the words used. A similar analysis of eye movement latencies shows that the percentage of variance they uniquely share either with lexical decision times or with naming times is much lower. It is 5–17% for gaze durations and lexical decision times in studies with target words presented in neutral sentences, but drops to 0.2% for corpus studies in which eye movements to all words are analysed. Correlations between gaze durations and naming latencies are lower still. These findings suggest that processing times in isolated word processing and continuous text reading are affected by specific task demands and presentation format, and that lexical decision times and naming times are not very informative in predicting eye movement latencies in text reading once the effect of word frequency and word length are taken into account. The difference between controlled experiments and natural reading suggests that reading strategies and stimulus materials may determine the degree to which the immediacy-of-processing assumption and the eye–mind assumption apply. Fixation times are more likely to exclusively reflect the lexical processing of the currently fixated word in controlled studies with unpredictable target words rather than in natural reading of sentences or texts.     

Speech Perception Among School-Aged Skilled and Less Skilled Readers

This study investigated the relationship between speech perception, phonological processing and reading skills among school-aged children classified as ‘skilled’ and ‘less skilled’ readers based on their ability to read words, decode non-words, and comprehend short passages. Three speech perception tasks involving categorization of speech continua differing in voicing, place and manner of articulation were administered and compared to phonological processing skills in phonological awareness, speeded naming and verbal short-term memory. The results obtained suggested that (a) speech categorization among skilled readers differed from that of less skilled readers, (b) speech perception skills were associated with both reading and phonological processing skills among both skilled and less skilled readers, however, (c) a strong association between speeded naming and both word and passage reading skills found among skilled readers was absent among less skilled readers. These results suggested that phonological representations and/or activation may not be as well developed in less skilled readers.     

Symbol-string sensitivity and adult performance in lexical decision

In this study of adult readers, we used a symbol-string task to assess participants' sensitivity to the position of briefly presented, non-alphabetic but letter-like symbols. We found that sensitivity in this task explained a significant proportion of sample variance in visual lexical decision. Based on a number of controls, we show that this relationship cannot be explained by other factors including: chronological age, intelligence, speed of processing and/or concentration, short term memory consolidation, or fixation stability. This approach represents a new way to elucidate how, and to what extent, individual variation in pre-orthographic visual and cognitive processes impinge on reading skills, and the results suggest that limitations set by visuo-spatial processes constrain visual word recognition.     

Reading ability is negatively related to Stroop interference

Stroop interference is often taken as evidence for reading automaticity even though young and poor readers, who presumably lack reading automaticity, present strong interference. Here the relationship between reading skills and Stroop interference was studied in a 7th-grade sample. Greater interference was observed in children diagnosed with reading disability (dyslexia) than in unimpaired children. Moreover, poorer reading skills were found to correlate with greater Stroop interference in the general school population. In correlation and regression analyses, interference was primarily associated with reading speed, with an additional unique contribution of reading accuracy. Color naming errors were few and not comparably related to reading skills. The relation of reading skill to Stroop interference was examined in computational modeling simulations. The production model of Roelofs [Roelofs, A. (2003). Goal-referenced selection of verbal action: modeling attentional control in the Stroop task. Psychological Review, 110, 88-125], in which interference is primarily due to word stimuli having direct access to word form encoding whereas color naming must pass through concept activation and lemma selection, was found to account well for the human data after imposing covariation constraints on parameters controlling word processing and blocking latency, in modifications not affecting the model's previous fit to other data. The connectionist model of Cohen, Dunbar, and McClelland [Cohen, J. D., Dunbar, K., & McClelland, J. L. (1990). On the control of automatic processes: a parallel distributed processing account of the Stroop effect. Psychological Review, 97, 332-361], in which interference is caused by differential route strength, implementing an automaticity account, approximated the observed patterns with network-wide parameter manipulations not specific to reading, such as processing speed and response threshold, likely to affect previously optimized performance. On the basis of the empirical and modeling data we argue for a direct link between reading skill and interference, beyond the effects of executive functioning.