Working memory, short-term memory, and speech rate as predictors of children's reading performance at different ages.

This study explored the contribution of 2 working memory (WM) systems (the phonological loop and the central executive) to reading performance in younger (9-year-old) and older (14-year-old) children. The results showed that (a) significant age-related differences in verbal and visual-spatial WM performance were maintained when articulation speed and short-term memory (the phonological system) were partialed from the analysis and (b) WM predicted age-related differences in word recognition and comprehension performance independent of the contribution of a short-term memory and articulatory rate. The results were interpreted as support for the notion that both the phonological and the executive systems are important predictors of age-related changes in reading but that these processes operate independent of each other in predicting fluent reading. Several implications of the results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory and intelligence in children: What develops?

This study explored the contribution of the phonological and executive working memory (WM) systems to 205 (102 girls, 103 boys, 6 to 9 years old) elementary school children's fluid and crystallized intelligence. The results show that (a) a 3-factor structure (phonological short-term memory [STM], visual-spatial WM, and verbal WM) was comparable between age groups, (b) controlled attention and STM storage accounted for 67% of the age-related variance in WM, (c) effect sizes for direct paths from WM were substantially larger when predicting fluid intelligence than crystallized intelligence, and (d) the contribution of STM to intelligence was isolated to reading. The results suggest that the development of WM is distinct from STM, controlled attention plus storage accounted for age-related WM changes, and WM underlies age-related changes in both fluid and crystallized intelligence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive processing deficits in poor readers with symptoms of reading disabilities and ADHD: More alike than different?

The cognitive differences among poor-reading children with characteristics of reading disabilities (RD) and attention deficit-hyperactivity disorder (ADHD) when compared with children with comorbid symptoms (RD + ADHD) and slow learners (SL) on measures of phonological and executive processing were investigated. No significant differences in performance emerged between the ability groups in phonological processing. The SL + ADHD & slow learners performed better than RD groups (RD alone and RD + ADHD) on the visual-spatial working memory (WM) factor score and the RD-alone group was inferior to RD + ADHD, SL + ADHD, and SL-alone groups on the verbal WM factor score. The results support the notion that poor readers, whether suffering from RD or ADHD symptoms, share a common phonological core deficit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Generality of Working Memory Capacity: A Latent-Variable Approach to Verbal and Visuospatial Memory Span and Reasoning.

A latent-variable study examined whether verbal and visuospatial working memory (WM) capacity measures reflect a primarily domain-general construct by testing 236 participants in 3 span tests each of verbal WM. visuospatial WM, verbal short-term memory (STM), and visuospatial STM. as well as in tests of verbal and spatial reasoning and general fluid intelligence (Gf). Confirmatory' factor analyses and structural equation models indicated that the WM tasks largely reflected a domain-general factor, whereas STM tasks, based on the same stimuli as the WM tasks, were much more domain specific. The WM construct was a strong predictor of Gf and a weaker predictor of domain-specific reasoning, and the reverse was true for the STM construct. The findings support a domain-general view of WM capacity, in which executive-attention processes drive the broad predictive utility of WM span measures, and domain-specific storage and rehearsal processes relate more strongly to domain-specific aspects of complex cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Text comprehension in Chinese children: Relative contribution of verbal working memory, pseudoword reading, rapid automated naming, and onset-rime phonological segmentation.

The present study examined the role of verbal working memory (memory span, tongue twister), 2-character Chinese pseudoword reading, rapid automatized naming (letters, numbers), and phonological segmentation (deletion of rimes and onsets) in inferential text comprehension in Chinese in 518 Chinese children in Hong Kong in Grades 3 to 5. It was hypothesized that verbal working memory, together with a small contribution from the other constructs, would explain individual variation in the children's text comprehension. Structural equation modeling and hierarchical multiple regression analyses generally upheld the hypotheses. Though Chinese pseudoword reading did not play an important mediating role in the effect of verbal working memory on text comprehension, verbal working memory had strong effects on pseudoword reading and text comprehension. The findings on the Chinese language support current Western literature as well as display the differential role of the constructs in Chinese reading comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Growth in literacy and cognition in bilingual children at risk or not at risk for reading disabilities.

This study investigated growth in reading, vocabulary, and memory in children (ages 5 to 10) learning English as a second language identified at risk for reading disabilities (RD). A growth curve analysis showed that RD children were significantly below children not at risk in English and Spanish reading, Spanish short-term memory (STM), Spanish comprehension, and English and Spanish working memory (WM). RD children were also inferior on growth measures of English and Spanish WM and Spanish STM. Growth on measures of Spanish vocabulary, reading, STM, and WM accounted for 12% of the variance in predicting growth in English reading. However, only Spanish measures of WM growth contributed unique variance. The results show that growth in WM in the primary language predicts growth in second-language reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relation among error detection, sentence verification, and low-level reading skills of fourth graders.

The author explored the relation among low-level reading skills, sentence verification, and error detection in 4th graders. Literal text comprehension was measured with the Sentence Verification Technique (J. M. Royer, in press) procedure. A higher (strategic) level of text comprehension was assessed with the error detection paradigm. Thus low- and high-level text comprehension were correlated with low-level reading skill: decoding, lexical access, verbal working memory span, and each other. Although literal text comprehension and low-level reading measures were correlated, both were uncorrelated with error detection. A second study deomonstrated that 4th graders' error detection was best predicted by their tendency to generate inferences while reading. These data suggest that although literal text comprehension is dependent on low-level reading processes, strategic reading competence reflects the 4th grader's tendency to go beyond literal information in a text. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cross-sectional and incremental changes in working memory and mathematical problem solving.

Cross-sectional and incremental age effects on cognitive processes that underlie individual differences in components of working memory (WM; phonological loop, visual-spatial sketchpad, executive processing) and mathematical problem-solving accuracy were examined in elementary schoolchildren. A battery of tests was administered that assessed problem solving, achievement, memory, and cognitive processing (inhibition, speed, phonological coding) in children in Grades 1, 2, and 3 (Wave 1) and 1 year later (Wave 2). The results showed that (a) 31% of the explainable within-person changes across testing waves and 42% of the age-related differences in word problem-solving accuracy were related to executive processing and (b) executive processing and reading performance in Year 1 were the only variables that contributed unique variance to Year 2 problem-solving performance. The results support the notion that growth in the executive system is an important predictor of children's problem solving abilities beyond the contribution of reading and calculation skills and that growth in executive processing can operate independently of individual differences in phonological processing, inhibition, and processing speed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Growth in working memory and mathematical problem solving in children at risk and not at risk for serious math difficulties.

The influence of cognitive growth in working memory (WM) on mathematical problem solution accuracy was examined in elementary school children (N = 353) at risk and not at risk for serious math problem solving difficulties. A battery of tests was administered that assessed problem solving, achievement, and cognitive processing (WM, inhibition, naming speed, phonological coding) in children in 1st, 2nd, and 3rd grade across 3 testing waves. The results were that (a) children identified as at risk for serious math problem solving difficulties in Wave 1 showed less growth rate and lower levels of performance on cognitive measures than did children not at risk; (b) fluid intelligence and 2 components of WM (central executive, visual-spatial sketchpad) in Wave 1 (Year 1) predicted Wave 3 word problem solving solution accuracy; and (c) growth in the central executive and phonological storage component of WM was related to growth in solution accuracy. The results support the notion that growth in WM is an important predictor of children's problem solving beyond the contribution of reading, calculation skills, and individual differences in phonological processing, inhibition, and processing speed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reading comprehension and working memory in learning-disabled readers: Is the phonological loop more important than the executive system?

This investigation explores the contribution of two working memory systems (the articulatory loop and the central executive) to the performance differences between learning-disabled (LD) and skilled readers. Performances of LD, chronological age (CA) matched, and reading level-matched children were compared on measures of phonological processing accuracy and speed (articulatory system), long-term memory (LTM) accuracy and speed, and executive processing. The results indicated that (a) LD readers were inferior on measures of articulatory, LTM, and executive processing; (b) LD readers were superior to RL readers on measures of executive processing, but were comparable to RL readers on measures of the articulatory and LTM system; (c) executive processing differences remained significant between LD and CA-matched children when measures of reading comprehension, articulatory processes, and LTM processes were partialed from the analysis; and (d) executive processing contributed significant variance to reading comprehension when measures of the articulatory and LTM systems were entered into a hierarchical regression model. In summary, LD readers experience constraints in the articulatory and LTM system, but constraints mediate only some of the influence of executive processing on reading comprehension. Further, LD readers suffer executive processing problems nonspecific to their reading comprehension problems.     

How are visuospatial working memory, executive functioning, and spatial abilities related? A latent-variable analysis.

This study examined the relationships among visuospatial working memory (WM) executive functioning, and spatial abilities. One hundred sixty-seven participants performed visuospatial short-term memory (STM) and WM span tasks, executive functioning tasks, and a set of paper-and-pencil tests of spatial abilities that load on 3 correlated but distinguishable factors (Spatial Visualization, Spatial Relations, and Perceptual Speed). Confirmatory factor analysis results indicated that, in the visuospatial domain, processing-and-storage WM tasks and storage-oriented STM tasks equally implicate executive functioning and are not clearly distinguishable. These results provide a contrast with existing evidence from the verbal domain and support the proposal that the visuospatial sketchpad may be closely tied to the central executive. Further, structural equation modeling results supported the prediction that, whereas they all implicate some degree of visuospatial storage, the 3 spatial ability factors differ in the degree of executive involvement (highest for Spatial Visualization and lowest for Perceptual Speed). Such results highlight the usefulness of a WM perspective in characterizing the nature of cognitive abilities and, more generally, human intelligence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive processes as predictors of word recognition and reading comprehension in learning-disabled and skilled readers: Revisiting the specificity hypothesis.

Examines how cognitive processes interrelate as well as predict learning-disabled (LD) readers' word recognition and reading comprehension performance. Correlations between phonological, orthographic, semantic, metacognitive, and working memory measures with reading performance were examined in LD and skilled readers (aged 8–12 yrs). LD Ss were deficient on all cognitive processes compared with skilled Ss, but these differences do not reflect IQ scores. Reading ability group differences emerged on a component composed primarily of working memory measures (referred to as "g") as well as unique components, suggesting that these differences emerge on both general and specific (modular) processes. G best predicts reading comprehension for both groups, and phonological awareness best predicts skilled Ss' pseudoword reading, whereas g best predicts LD Ss' pseudoword performance. Overall, LD Ss' information processing difficulties were described within a general working memory model that views such children as having difficulty accessing and coordinating both general and specific processes. Results suggest that the cognitive processes that contribute to reading deficits are best understood in the context of their combination with other operations rather than in isolation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Children's Reading Comprehension Ability: Concurrent Prediction by Working Memory, Verbal Ability, and Component Skills.

The authors report data from a longitudinal study that addresses the relations between working memory capacity and reading comprehension skills in children aged 8, 9, and 11 years. At each time point, the authors assessed children's reading ability, vocabulary and verbal skills, performance on 2 working memory assessments (sentence-span and digit working memory), and component skills of comprehension. At each time point, working memory and component skills of comprehension (inference making, comprehension monitoring, story structure knowledge) predicted unique variance in reading comprehension after word reading ability and vocabulary and verbal ability controls. Further analyses revealed that the relations between reading comprehension and both inference making and comprehension monitoring were not wholly mediated by working memory. Rather, these component skills explained their own unique variance in reading comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Literacy and Cognitive Functioning in Bilingual and Nonbilingual Children at or Not at Risk for Reading Disabilities.

The authors determined whether the cognitive processes that underlie second-language acquisition difficulties are the same as those that underlie reading difficulties. First-grade (N = 101) bilingual and nonbilingual children were administered a battery of measures in Spanish and English. English word identification and vocabulary were predicted by a language-general working-memory (WM) factor, whereas English pseudoword reading was predicted by Spanish pseudoword reading and WM. The results also showed that (a) children proficient in language were better able to access resources from WM and (b) children with reading disabilities (RD) performed poorly on Spanish measures of short-term memory. In general, second-language difficulties are related to accessing a language-independent WM system, whereas language-specific phonological memory deficits underlie RD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory in learning disability subgroups

The purpose of this study was to investigate (a) the degree to which working memory differences between learning-disabled and nondisabled children reflect a specific or generalized deficit, and (b) whether limitations in the enhancement of learning-disabled student's working memory performance are attributable to process or storage functions. To this end, performances of reading-disabled, math-disabled, chronological age (CA)-matched, and achievement-matched children were compared on verbal and visual-spatial working memory measures under initial, gain, and maintenance conditions. The results indicated that: (a) learning-disabled subtypes were not differentiated by their performance on verbal and visual-spatial working memory measures; and (b) learning-disabled children's working memory performance was inferior to CA-matched and superior to achievement-matched counterparts across initial, gain, and maintenance conditions. The results suggest that learning-disabled children suffer generalized working memory deficits, possibly due to storage constraints in the executive system.     

Predictive ability of the General Ability Index (GAI) versus the Full Scale IQ among gifted referrals.

The General Ability Index (GAI) is a composite ability score for the Wechsler Intelligence Scale for Children—Fourth Edition (WISC–IV) that minimizes the impact of tasks involving working memory and processing speed. The goal of the current study was to compare the degree to which the Full Scale IQ (FSIQ) and the GAI predict academic achievement in math and reading among a group of 88 children tested for gifted programming. All students had significant variability among their index scores on the WISC–IV. Whereas both the FSIQ and GAI significantly predicted standardized achievement test scores in reading and math, the FSIQ explained more of the variance. In sequential regression analyses, both working memory and verbal comprehension scores explained significant, unique variance in reading and math scores. However, measures of processing speed and perceptual reasoning did not account for significant amounts of variance in achievement scores over and above measures of working memory and verbal comprehension. The inclusion of working memory scores in calculation of the FSIQ appears to account for the difference in prediction between the FSIQ and the GAI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Relationship Between Working Memory and Mathematical Problem Solving in Children at Risk and Not at Risk for Serious Math Difficulties.

This study identified cognitive processes that underlie individual differences in working memory (WM) and mathematical problem-solution accuracy in elementary school children at risk and not at risk for serious math difficulties (SMD). A battery of tests was administered that assessed problem solving, achievement, and cognitive processing in children in first (N = 130), second (N = 92) and third grades (N = 131). The results were that (a) younger children and children at risk for SMD performed poorer on WM and problem-solving tasks, as well as measures of math calculation, reading, semantic processing, phonological processing, and inhibition, than older children and children not at risk for SMD and (b) WM predicted solution accuracy of word problems independent of measures of fluid intelligence, reading skill, math skill, knowledge of algorithms, phonological processing, semantic processing,'speed, shortterm memory, and inhibition. The results support the notion that the executive system is an important predictor of children's problem solving. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory, attention control, and the n-back task: A question of construct validity.

The n-back task requires participants to decide whether each stimulus in a sequence matches the one that appeared n items ago. Although n-back has become a standard "executive" working memory (WM) measure in cognitive neuroscience, it has been subjected to few behavioral tests of construct validity. A combined experimental- correlational study tested the attention-control demands of verbal 2- and 3-back tasks by presenting n = 1 "lure" foils. Lures elicited more false alarms than control foils in both 2- and 3-back tasks, and lures caused more misses to targets that immediately followed them compared with control targets, but only in 3-back tasks. N-back thus challenges control over familiarity-based responding. Participants also completed a verbal WM span task (operation span task) and a marker test of general fluid intelligence (Gf; Ravens Advanced Progressive Matrices Test; J. C. Raven, J. E. Raven, & J. H. Court, 1998). N-back and WM span correlated weakly, suggesting they do not reflect primarily a single construct; moreover, both accounted for independent variance in Gf. N-back has face validity as a WM task, but it does not demonstrate convergent validity with at least 1 established WM measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resilient readers? University students who are poor recoders but sometimes good text comprehenders.

The authors screened 194 university students to determine whether some could comprehend text well despite very poor recoding skills, measured by pseudoword reading. Most of the 17 poorest recoders had never been identified as reading disabled. We classified 6 poor recoders as "resilient readers" because their text comprehension scores were average or above, relative to the sample as a whole. They were indistinguishable from 6 matched typical readers on measures of text comprehension derived from oral-reading think-aloud protocols. There was no evidence that the resilient readers relied on superior verbal ability or working memory to compensate for poor recoding. The resilient readers were poor at spelling, reading isolated words, and reading text rapidly, but they showed adequate phonemic awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)