H. Lee Swanson

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, short-term memory, and inhibition. The results support the notion that the executive system is an important predictor of childrens problem solving.

Experimental Intervention Research on Students with Learning Disabilities: A Meta-Analysis of Treatment Outcomes

This article summarizes a comprehensive synthesis of experimental intervention studies that have included students with learning disabilities. Effect sizes for 180 intervention studies were analyzed across instructional domains, sample characteristics, intervention parameters, methodological procedures, and article characteristics. The overall mean effect size of instructional intervention was positive and of high magnitude (M = 0.79). Effect sizes were more positive for a combined model that included components of direct and strategy instruction than for competing models. Interventions that included instructional components related to controlling task difficulty, small interactive groups, and directed responses and questioning of students were significant predictors of effect size, and interventions that varied from control conditions in terms of setting, teacher, and number of instructional steps yielded larger effect sizes than studies that failed to control for such variations. The results are supportive of the pervasive influence of cognitive strategy and direct instruction models for remediating the academic difficulties for children with learning disabilities.

Math Disabilities: A Selective Meta-Analysis of the Literature:

This article synthesizes published literature comparing the cognitive functioning of children who have math disabilities (MD) with that of (a) average-achieving children; (b) children who have reading disabilities (RD); and (c) children who have comorbid disabilities (MD+RD). Average achievers outperformed children with MD on measures of verbal problem solving, naming speed, verbal working memory (WM), visual-spatial WM, and long-term memory (LTM). Children with MD outperformed comorbid children on measures of literacy, visual-spatial problem solving, LTM, short-term memory (STM) for words, and verbal WM. Children with MD could be differentiated from children with RD only on naming speed and visual-spatial WM. Differences in cognitive functioning between children with MD and average achievers were related primarily to verbal WM when the effects of all other variables (e.g., age, IQ, and other domain categories) were partialed out.

Rapid Naming, Phonological Awareness, and Reading: A Meta-Analysis of the Correlation Evidence

This study provides a meta-analysis of the correlational literature on measures of phonological awareness, rapid naming, reading, and related abilities. Correlations (N = 2,257) were corrected for sample size, restriction in range, and attenuation from 49 independent samples. Correlations between phonological awareness (PA) and rapid naming (RAN) were low (.38) and loaded on different factors. PA and RAN were moderately correlated with real-word reading (.48 and .46, respectively). Other findings were that (a) real-word reading was correlated best (r values were .60 to .80) with spelling and pseudoword reading, but correlations with RAN, PA, vocabulary, orthography, IQ, and memory measures were in the low-to-moderate range (.37 to .43); and (b) correlations between reading and RAN/PA varied minimally across age groups but were weaker in poor readers than in skilled readers. The results suggested that the importance of RAN and PA measures in accounting for reading performance has been overstated.

What develops in working memory? A life span perspective.

This study investigated whether working-memory (WM) span differences across age are attributable to specific or general processing functions. The study compared 9 age groups (6, 8, 10, 13, 16, 24, 35, 45, 57 years) on verbal and visuospatial WM performance under initial (no probes or cues), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). (a) Age-related performance differences in WM were found across all conditions and were not isolated to specific processes, (b) significant performance differences remained among age groups on gain and maintenance conditions, and (c) the gain (accessing new information) and maintenance conditions (maintenance of old information) for verbal and visuospatial WM tasks contributed independent variance to age-related performance. The results support a general capacity explanation of age-related differences. These differences in capacity reflect demands placed on both the accessing of new information and the maintenance of old information.

Developmental skills related to writing and reading acquisition in the intermediate grades

Multiple measures of the fine motor system, the orthographic system, the phonological system, the working memory system, the verbal intelligence system, the writing system, and the reading system were administered to 300 students in grades 4, 5, and 6. Results showed that the writing system and the reading system share many of the same orthographic, phonological, and working memory sub-processes but thepatterns of concurrent relation between these sub-processes and writing and between these subprocesses and reading differ. These results are consistent with the view that writing and reading draw upon the same as well as unique cognitive systems.

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 childrens problem solving beyond the contribution of reading, calculation skills, and individual differences in phonological processing, inhibition, and processing speed.

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.

Individual and age-related differences in children’s working memory

The purpose of this study was to investigate the degree to which age-related and individual differences in children’s working memory (WM) are due to a general or task-specific capacity system. Experiment 1 correlated children’s (N=146; age range 5–19 years) verbal and visual-spatial working memory performance with various intelligence and achievement measures. The results supporting a general system were that (1) visual-spatial and verbal WM measures were significantly intercorrelated with and without age partialed out and (2) both verbal and visual-spatial WM measures were significantly correlated with diverse achievement and intelligence measures. Experiment 2 compared three age groups (N=192; 7-, 10-, and 13-year-olds) on working-memory performance tasks under initial, enhanced (cued), and maintenance conditions. The results supporting a general capacity system were that (1) age-related performance differences in WM were found on all conditions and not isolated to specific processes, (2) the maintenance measures (high-load condition) predicted the variance better in age-related performance than process measures, and (3) although individual differences in WM performance reflected two independent operations, these operations produced similar correlations to achievement within age groups. Overall, the results support a general capacity explanation of age-related and individual differences in children’s WM performance.

COGNITION, METACOGNITION, AND ACHIEVEMENT OF COLLEGE STUDENTS WITH LEARNING DISABILITIES

This study examined the way successful college students with LD compensated for their deficits in phonological processing. Successful was defined as average or above-average grades in college coursework. The study compared the cognitive and metacognitive performance of students with and without LD (N=40). Although achievement levels for both groups were comparable, students with LD scored significantly lower than students without LD in word reading, processing speed, semantic processing, and short-term memory. Differences were also found between groups in self-regulation and number of hours of studying. Results showed that students with LD compensated for their processing deficits by relying on verbal abilities, learning strategies, and help seeking.