工作记忆与学习能力的关系

工作记忆是一种对信息进行暂时加工和贮存的能量有限的记忆系统,工作记忆通过阅读理解、写作和数学问题解决而影响学生的学习能力。语音回路对阅读的影响更多地体现在复杂句子结构的理解上,中央执行功能在语言意义的加工过程中起着更大的作用,写作能力的逐步完善与工作记忆能力的增长密不可分,工作记忆的三个成分对简单和复杂数学问题解决都产生重要影响。     

Specific impairment in developmental reading disabilities: a working memory approach

Children with developmental reading disabilities (RD) frequently display impaired working memory functioning. However, research has been divergent regarding the characteristics of the deficit. Our investigation addressed this controversy by assessing Baddeley's working memory model as a whole rather than focusing on particular aspects of it, as has been done by much of the research to date. Participants included 20 children with RD and 20 typical readers between the ages of 9 and 13. The phonological loop, visual-spatial sketchpad, and central executive were assessed according to Baddeley's model. The results demonstrated that children with RD have an impaired phonological loop but intact visual-spatial sketchpad and central executive functioning as compared to controls. In terms of the phonological loop, the deficit appears to be specific to the phonological store. Furthermore, our research supports a relationship between phonological processing and phonological loop functioning.     

Modeling Phonological Core Deficits Within a Working Memory Architecture in Children and Adults With Developmental Dyslexia

Recent theoretical advances in working memory guided analyses of cognitive measures in 122 children with dyslexia and their 200 affected biological parents in families with a multigenerational history of dyslexia. Both children and adults were most severely impaired, on average, in three working memory components— phonological word-form storage, time-sensitive phonological loop, and executive functions involving phonology. Structural equation modeling showed that, for children, first-order factors from the phonological, orthographic, and/or morphological word forms uniquely predicted 11 reading and writing outcomes but, for adults, a second-order factor (reflecting interrelationships among the three first-order word-form factors) was more likely to be significant in predicting the same reading and writing outcomes. Structural equation modeling of the three working memory component factors showed that the most consistent predictor of text-level reading and writing for both children and adults was the second-order word-form factor. Phonological loop and executive support could be modeled as separate factors in children but only as combined factors in adults. Executive support in children and combined phonological loop and executive support in adults contributed uniquely to oral reading but did not contribute uniquely to reading comprehension or written expression. For both children and adults, individual differences occurred as to which of the three working memory components or three word forms fell outside the normal range.     

Working memory deficits in children with specific learning disorders

This article examines working memory functioning in children with specific developmental disorders of scholastic skills as defined by ICD-10. Ninety-seven second to fourth graders with a minimum IQ of 80 are compared using a 2 x 2 factorial (dyscalculia vs. no dyscalculia; dyslexia vs. no dyslexia) design. An extensive test battery assesses the three subcomponents of working memory described by Baddeley (1986): phonological loop, visual-spatial sketchpad, and central executive. Children with dyscalculia show deficits in visual-spatial memory; children with dyslexia show deficits in phonological and central executive functioning. When controlling for the influence of the phonological loop on the performance of the central executive, however, the effect is no longer significant. Although children with both reading and arithmetic disorders are consistently outperformed by all other groups, there is no significant interaction between the factors dyscalculia and dyslexia.     

Reading ability and short-term memory: The role of phonological processing

The aim of the current study was to further explore the connection between verbal short-term recall and phonological processing for two purposes: (a) To investigate the basis of short-term memory deficits for children with reading disability, and (b) To further explore the origin of developmental verbal memory span increases.Using a variety of memory and phonological tasks, reading group comparisons were conducted testing third-grade good readers and poor readers, and developmental changes were studied with pre-kindergarten, first-grade and third-grade children. The main finding was that a strong relationship was observed between efficiency of phonological processes and capacity of verbal memory supporting the hypothesis that reducing phonological processing requirements in verbal short-term memory increases available resources for storage. No such relationship was found between phonological processing and nonverbal memory. This conclusion was supported by two findings: (a) The verbal short-term memory deficits in poor readers significantly correspond with less accurate phonological processing, and (b) Developmental increases in verbal STM are accompanied by more accurate and rapid execution of phonological tasks.     

Short-term memory,phonological processing,and reading ability

Verbal short-term memory deficits are a common characteristic of children with reading problems and may markedly increase the difficulty of learning to read. Previous work suggests that the basis of the short-term memory deficit may involve limitations in phonetic coding. In the present paper, a series of experiments are reviewed which examined the role of phonological processes in short-term memory. First, a developmental study is described in which a significant relationship was found between phonetic processes and verbal memory span, but not between phonetic processes and nonverbal memory. Second, additional studies are reviewed which collectively found that children with reading problems are less accurate at phonetic encoding than are good readers, and that performance on phonetic processing corresponds with verbal memory span. No reading group differences were obtained on nonverbal perception or memory tasks. These findings suggest that both developmental and individual differences in verbal memory span are related to the efficiency of phonological processes. Practical implications of current cognitive research are discussed. The research was supported by NIH Grant HD-01994 to Haskins Laboratories.     

State anxiety and working memory in children: A test of processing efficiency theory

This study investigated the effect of individual differences in state anxiety on tasks tapping the central executive, phonological, and visuo‐spatial components of working memory (WM). It was designed to test Eysenck and Calvo’s processing efficiency theory (PET) which suggests that the phonological and executive components of WM may be important in understanding learning outcomes in anxiety. Typically‐developing children aged 9–10 years were split into high and low state anxiety groups. They performed three WM tasks – forward and backward digit span (assumed to measure phonological and central executive components of WM respectively) and a spatial working memory task (measuring the visuo‐spatial component of WM). Measurements of task accuracy were taken as an indicator of performance outcome or effectiveness. Time taken to complete tasks and a subjective rating of mental effort were taken as measurements of performance efficiency. No differences were found between high and low state anxiety groups in task accuracy for any measure. Children in the high state anxiety group, however, took longer to complete the backward digit span task and reported increased mental effort in the forward digit span task, indicating some effect of anxiety on measures of performance efficiency.     

Differential contribution of specific working memory components to mathematics achievement in 2nd and 3rd graders

The contribution of the three core components of working memory (WM) to the development of mathematical skills in young children is poorly understood. The relation between specific WM components and Numerical Operations, which emphasize computation and fact retrieval, and Mathematical Reasoning, which emphasizes verbal problem solving abilities in 48 2nd and 50 3rd graders was assessed using standardized WM and mathematical achievement measures. For 2nd graders, the central executive and phonological components predicted Mathematical Reasoning skills; whereas the visuo-spatial component predicted both Mathematical Reasoning and Numerical Operations skills in 3rd graders. This pattern suggests that the central executive and phonological loop facilitate performance during early stages of mathematical learning whereas visuo-spatial representations play an increasingly important role during later stages. We propose that these changes reflect a shift from prefrontal to parietal cortical functions during mathematical skill acquisition. Implications for learning and individual differences are discussed.     

Theory of mind,directly and indirectly,facilitates kindergarten adjustment via verbal ability,executive function,and emotion knowledge

Theory of mind describes the ability to engage in perspective‐taking, understand intentions, and predict actions and emotions. Theory of mind typically achieves major developmental milestones around age of 5, coinciding with the transition to kindergarten, and is associated with a verbal ability (receptive and expressive vocabulary), executive function (inhibitory control and working memory), and emotion knowledge. Less is known about how the theory of mind operates in low‐income samples, where foundational skills (i.e., verbal ability, executive function, and emotion knowledge) tend to be delayed. Applied to classrooms, the theory of mind may support the transition to kindergarten by facilitating relationships, learning‐related behaviors, and socioemotional skills that require perspective‐taking. In a low‐income sample of 140 kindergarteners across 21 classrooms, the theory of mind was directly associated with teacher‐ratings of social and emotional skills, behavioral and academic adjustment, and closeness within the teacher–child relationship, beyond the contribution of foundational skills. Moreover, verbal ability, executive function, and emotion knowledge were indirectly associated with outcomes through the theory of mind. Findings suggest the theory of mind facilitates the transition to kindergarten and is built upon a complex set of foundational skills.     

学习不良者的工作记忆特点

有关学习不良者的工作记忆特点的研究表明,阅读不良者与数学学习不良者都存在语音回路功能缺陷(如语音表征的效率低)以及中央执行器功能缺陷(如对注意控制的能力不足) ,即学习不良与工作记忆缺陷密切相关。今后的研究应进一步探明学习不良者工作记忆缺陷的深层原因。     

Phonological awareness,verbal working memory and the acquisition of literacy

This paper describes a 2-year longitudinal study of 76 initially prereading children. The study examined the relationships between phonological awareness (measured by tests of onset and rime, phonemic segmentation and phoneme deletion), verbal working memory and the development of reading and spelling. Factor analyses showed that the verbal working memory tests which were administered loaded on two distinct but highly related factors, the first of which,simple repetition, involved the repetition of verbal items exactly as spoken by the experimenter, whereas the second,backwards repetition, involved repetition of items in reverse order. Factor analyses also showed that, whist the phonological awareness variables consistently loaded on the backwards repetition factor at the beginning and end of Grade 1, by Grade 2 the phonological awareness variables loaded on a separate factor which also included sentence repetition. Results of multiple regression analyses, with reading and spelling as a compound criterion variable, indicated that phonological awareness consistently predicted later reading and spelling even when both simple and backwards repetition were controlled. In contrast, verbal working memory did not consistently predict reading and spelling across testing times. Whilst there was some indication that verbal working memory, especially backwards repetition, measured during Grade 1 did predict reading and spelling in Grade 2, these effects were no longer evident when all three phonological variables were controlled. Nevertheless, with 4 individual reading and 2 individual spelling measures as the criterion variables, it was shown that phonological awareness was not quite such a consistent predictor of reading and spelling: it was most highly related to reading pseudowords and spelling real words; but it was not so highly related to spelling pseudowords, apparently because the processing demands of the task for the young children in the study were extremely high. Given the importance of verbal working memory for the completion of phonological awareness, reading and spelling tasks, in particular for spelling pseudowords, the findings are interpreted as providing some support for a theoretical position which posits that both phonological awareness and verbal working memory contribute to the early stages of literacy acquisition. Whilst the findings suggest some support for a general underlying phonological ability, there is also evidence that, as children learn to read and write, verbal working memory and phonological awareness become more differentiated.     

How working memory relates to children’s reading comprehension: the importance of domain-specificity in storage and processing

Working memory is considered a well-established predictor of individual variation in reading comprehension in children and adults. However, how storage and processing capacities of working memory in both the phonological and semantic domain relate to reading comprehension is still unclear. In the current study, we investigated the contribution of phonological and semantic storage, and phonological and semantic processing to reading comprehension in 123 Dutch children in fifth grade. We conducted regression and mediation analyses to find out to what extent variation in reading comprehension could be explained by storage and processing capacities in both the phonological and the semantic domain, while controlling for children’s decoding and vocabulary. The analyses included tasks that reflect storage only, and working memory tasks that assess processing in addition to storage. Regression analysis including only storage tasks as predictor measures, revealed semantic storage to be a better predictor of reading comprehension than phonological storage. Adding phonological and semantic working memory tasks as additional predictors to the model showed that semantic working memory explained individual variation in reading comprehension over and above all other memory measures. Additional mediation analysis made it clear that semantic storage contributed indirectly to reading comprehension via semantic working memory, indicating that semantic storage tapped by working memory, in addition to processing capacities, explains individual variation in reading comprehension. It can thus be concluded that semantic storage plays a more important role in children’s reading comprehension than previously thought.     

Developmental dyslexia: Related to specific or general deficits?

The present study was designed to examine the question of whether developmental dyslexia in 12-year-old students at the beginning of secondary education in the Netherlands is confined to problems in the domain of reading and spelling or also is related to difficulties in other areas. In particular, hypotheses derived from theories on phonological processing, rapid automatized naming, working memory, and automatization of skills were tested. To overcome the definition and selection problems of many previous studies, we included in our study all students in the first year of secondary special education in a Dutch school district. Participants were classified as either dyslexic, garden-variety, or hyperlexic poor readers, according to the degree of discrepancy between their word recognition and listening comprehension scores. In addition, groups of normal readers were formed, matching the poor readers in either reading age or chronological age. A large test battery was administered to each student, including phonological, naming, working memory, speed of processing, and motor tests. The findings indicate that dyslexia is associated with deficits in (1) phonological recoding, word recognition (both in their native Dutch and in English as a second language), and spelling skills; and (2) naming speed for letters and digits. Dyslexia was not associated with deficits in other areas. The results suggest that developmental dyslexia, at the age of 12, might be (or might have become) a difficulty rather isolated from deficiencies in other cognitive and motor skills.     

Learning novel phonological representations in developmental dyslexia: associations with basic auditory processing of rise time and phonological awareness

Across languages, children with developmental dyslexia are known to have impaired lexical phonological representations. Here, we explore associations between learning new phonological representations, phonological awareness, and sensitivity to amplitude envelope onsets (rise time). We show that individual differences in learning novel phonological representations are related to individual differences in both rise time categorization and rise time discrimination when non-verbal IQ and short-term memory skills are controlled. This is consistent with the developmental claim that difficulties in the basic auditory processing of rise time cause difficulties in setting up the phonological lexicon from infancy, leading to impairments in phonological awareness.     

Young readers' use of phonological information: phonological awareness, memory, and comprehension

In this study, we explored the relationship between beginning readers' phonological awareness and other aspects of phonological processing, specifically as manifested in short-term memory and comprehension tasks. The theoretical questions underlying the study were (a) what roles phonological processes play in children's beginning reading, from word identification through sentence comprehension, and (b) whether those roles are sufficiently related that potential difficulties at one level directly affect processing at other levels. Phonologically induced effects were observed for word-list memory and for sentence judgments for both novice readers (at the end of kindergarten) and relatively more experienced readers (end of Grades 1 and 2). For both age groups, correlational analyses revealed relationships among phonological awareness, phonological processing in list memory, and word reading. However, phonological processing in sentence comprehension was not related to other types of phonological processing. These results indicate that although phonology plays a role during comprehension, phonological processing may not be as limiting a factor in comprehension as in word reading.     

Mixture growth models of RAN and RAS row by row: insight into the reading system at work over time

Children (n = 122) and adults (n = 200) with dyslexia completed rapid automatic naming (RAN) letters, rapid automatic switching (RAS) letters and numbers, executive function (inhibition, verbal fluency), and phonological working memory tasks. Typically developing 3rd (n = 117) and 5th (n = 103) graders completed the RAS task. Instead of analyzing RAN/RAS results the usual way (total time), growth mixture modeling assessed trajectories of successive times for naming 10 symbols in each of five rows. For all three samples and both RAN and RAS, two latent classes were identified. The “faster” class performed slowly on the first row and increased time by small increments on subsequent rows. The “slower” latent class performed more slowly on the first row, and children, but not adults, increased time by larger increments on subsequent rows. For children, both the initial row (automaticity index) and slope (sustained controlled processing index) of the trajectory differentiated the classes. For adults, only the initial row separated the classes. The longest time was on row 3 for RAN and row 4 for RAS. For the typically developing 5th graders, close in age to the children with dyslexia, the trajectories were flatter than for children with dyslexia and only the slower class (4%) showed the peak on row 4. For children with dyslexia, inhibition predicted RAN slope within the slower latent class and phonological working memory predicted RAS slope for both latent classes. For adults with dyslexia, inhibition and phonological working memory differentiated both latent classes on RAN intercept and RAS slope. Taken together, RAN, which may assess the phonological loop of working memory, and RAS, which may assess the central executive in working memory, may explain the timing deficit in dyslexia in sustaining coordinated orthographic-phonological processing over time. This research was supported by Grant Ns. P50 33812 and R01 HD25858 from the National Institute of Child Health and Human Development, Virginia W. Berninger, PI.     

Do different components of working memory underlie different subgroups of reading disabilities?

The purpose of this study was to determine the components of working memory (WM) that underlie less skilled readers' comprehension and word recognition difficulties. Performance of 3 less skilled reading subgroups---children with reading disabilities (RD) in both word recognition and comprehension; children with comprehension deficits only; and children with low verbal IQ, word recognition, and comprehension (poor readers)--was compared to that of skilled readers on WM, short-term memory (STM), processing speed, executive, and phonological processing measures. Ability group comparisons showed that (a) skilled readers outperformed all less skilled readers on measures of WM, updating, and processing speed; (b) children with comprehension deficits only outperformed children with RD on measures of WM, STM, phonological processing, and processing speed; and (c) children with RD outperformed poor readers on WM and phonological processing measures. A hierarchical regression analysis showed that (a) subgroup differences on WM tasks among less skilled readers were moderated by a storage system not specific to phonological skills, and (b) STM and updating contributed significant variance to WM beyond what was contributed by reading group classification. The latter finding suggested that some differences in storage and executive processing emerged between skilled and less skilled readers that were not specific to reading.     

Phonological Analysis Skills, Verbal Working Memory, and Reading Ability in Second-Grade Children

This study tested the hypothesis that phonological analysis skills make a unique contribution to reading ability against the hypothesis that one latent phonological factor underlies the assocations among analysis skills, verbal working memory skills, and reading achievement. Hierachical multiple regression analyses examined the unique contributions of phonological analysis and verbal working memory measures to the prediction of 3 measures of concurrent reading ability in 68 second-grade children (mean age 7 years 4 months). Phonological analysis and verbal working memory measures each accounted for unique variation in each of the 3 reading measures. In addition, phonological analysis measures, but not verbal working memory measures, were particularly strong predictors of pseudoword reading skills. These results suggest that, although phonological analysis and verbal working memory skills share a substantial amount of common variance, phonological analysis and verbal working memory tasks do tap somewhat different reading-related skills.     

Distinctive working memory profiles in children with special educational needs

The working memory skills of children with four categories of special educational needs (SEN) were investigated: general learning difficulties, language problems, literacy problems, and attentional and behavioural problems. Children with general learning difficulties performed poorly on measures of all three components of the working memory model: the phonological loop, central executive, and the visuo‐spatial sketchpad. Children with problems specific to language had impairments of the phonological loop and the central executive only. The working memory abilities of the groups with literacy and behavioural problems fell within the normal range. These findings are explained in terms of specific roles played by components of working memory in supporting learning activities.     

Development of Working Memory from Grade 3 to 5: Differences between Children With and Without Mathematical Learning Difficulties

Based on the finding that children with mathematical learning difficulties (MLD) have deficits in working memory (WM), the question arises as to whether these children differ from typical learners only in the level or also in the developmental trajectories of WM functioning. To this end, the WM of 80 children with MLD and 71 typical learners was assessed longitudinally from third to fifth grade. Typical learners outperformed children with MLD in the phonological, visuospatial and central executive WM functioning in third grade. Latent change analyses indicated that both phonological and central executive WM functioning developed in a parallel pattern in children with MLD and in typical learners. In contrast, visuospatial WM functioning revealed a different development in children with and without MLD since the gap between both groups decreased over time. Overall, despite starting at a lower level, the WM functioning in children with MLD did not develop more slowly.