The structure of working memory and how it relates to intelligence in children

Longitudinal Relations Among Executive Function, Theory of Mind, and Japanese Language Skills Achievement in Elementary School: A 4-year Longitudinal Study

This longitudinal study investigated the roles of elementary schoolers' executive function (EF) and theory of mind (ToM) as predictors in their academic achievements in Japanese language skills (e.g., speaking and listening ability, writing ability, reading ability, and linguistic knowledge) from first through fifth grade. We assessed the EF, ToM, and academic achievements of 85 Japanese elementary schoolers, when they were grade 1 (M = 90.19 months) and grade 3 (M = 114.34 months). Moreover, academic achievements of same children tested in grade 5 (M = 137.92 months). A path analysis revealed that EF abilities in Grades 1 and 3 predicted Japanese language achievement via ToM ability, and EF and ToM in Grade 1 had an indirect effect on achievements in Grades 3 and 5. Further, Japanese language skills achievement in Grade 1 predicted EF ability in Grade 3 and EF predicted achievement in Grade 5. These findings indicate the vital role of elementary schoolers' EF on academic achievement in Japan.

Sex differences in brain-behavior relationships in the first two years of life

Background

Evidence for sex differences in cognition in childhood is established, but less is known about the underlying neural mechanisms for these differences. Recent findings suggest the existence of brain-behavior relationship heterogeneities during infancy; however, it remains unclear whether sex underlies these heterogeneities during this critical period when sex-related behavioral differences arise.

Methods

A sample of 316 infants was included with resting-state functional magnetic resonance imaging scans at neonate (3 weeks), 1, and 2 years of age. We used multiple linear regression to test interactions between sex and resting-state functional connectivity on behavioral scores of working memory, inhibitory self-control, intelligence, and anxiety collected at 4 years of age.

Results

We found six age-specific, intra-hemispheric connections showing significant and robust sex differences in functional connectivity-behavior relationships. All connections are either with the prefrontal cortex or the temporal pole, which has direct anatomical pathways to the prefrontal cortex. Sex differences in functional connectivity only emerge when associated with behavior, and not in functional connectivity alone. Furthermore, at neonate and 2 years of age, these age-specific connections displayed greater connectivity in males and lower connectivity in females in association with better behavioral scores.

Conclusions

Taken together, we critically capture robust and conserved brain mechanisms that are distinct to sex and are defined by their relationship to behavioral outcomes. Our results establish brain-behavior mechanisms as an important feature in the search for sex differences during development.

Comprehension of irony in autistic children: The role of theory of mind and executive function

Although previous studies have examined irony comprehension in autistic children and potential impact factors, the relationship between theory of mind (ToM), executive function (EF), symptoms of autism, and comprehension of irony in this population remains largely unknown. This study explored irony comprehension in autistic children and examined the roles of ToM and EF in linking autism symptoms to deficits in irony comprehension. Twenty autistic children were compared with 25 typically developing (TD) children in an irony story picture task, ToM task, and EF task. The results showed that autistic children had impaired comprehension of irony compared with TD children, and performance on ironic stories showed a significant moderate discriminatory effect in predicting autistic children. A ToM deficit has also been proposed for autistic children. Comprehension of irony was significantly correlated with second-order ToM (2nd ToM) but was not significantly correlated with any components of EF. Moreover, 2nd ToM can predict the level of irony comprehension and mediate the relationship between symptoms of autism and irony comprehension. Taken together, these findings suggest that irony comprehension may offer a potential cognitive marker for quantifying syndrome manifestations in autistic children, and 2nd ToM may provide insight into the theoretical mechanism underlying the deficit in irony comprehension in this population.

Case Report: A playful digital-analogical rehabilitative intervention to enhance working memory capacity and executive functions in a pre-school child with autism

Background

Autism Spectrum Disorder (ASD) is often associated with deficits in Working Memory Capacity (WMC) and Executive Functions (EFs), as early as the first years of life. Research has shown that, even young children with ASD, WMC and EF deficits can be effectively addressed through interventions employing digital and/or analogical tools. Early intervention is important because executive dysfunction can negatively impact on the quality of life, both of children and their families. However, very few studies have been carried out involving intervention with pre-schoolers with ASD. To fill this gap, we developed an intervention that promotes pre-schoolers' WMC and EFs by employing both digital apps and analogical playful activities. This study reports on the feasibility of this intervention, which was carried out in a rehabilitative context.

Methods

A male pre-schooler diagnosed with ASD was engaged in a total of 17 intervention sessions, all held in a clinical context, over a nine-week period. Outcomes were measured using a battery of pre- and post-treatment tasks focusing on WMC, EFs and receptive language. The clinician who administered the intervention made written observations and noted any improvements in the child's performance emerging from the digital and analogical activities.

Results

The pre- and post-test scores for the cognitive tasks revealed qualitative improvements in the following cognitive domains: (a) WMC in the language receptive domain; (b) updating in WMC; (c) inhibition, specifically concerning control of motor response; (d) receptive vocabulary. Furthermore, when monitoring the child's performance, the clinician noted improvement in almost all the playful activities. Particularly notable improvements were observed in interaction with the apps, which the child appeared to find very motivating.

Conclusion

This study supports feasibility of a playful digital-analogical intervention conducted by a clinician in a rehabilitation context to promote cognitive abilities in pre-schoolers with ASD. Further studies are needed to establish whether the intervention's effectiveness can be generalized to a broad sample of children with ASD.

The Structure of Working Memory and Its Relationship with Intelligence in Japanese Children

There is a host of research on the structure of working memory (WM) and its relationship with intelligence in adults, but only a few studies have involved children. In this paper, several different WM models were tested on 170 Japanese school children (from 7 years and 5 months to 11 years and 6 months). Results showed that a model distinguishing between modalities (i.e., verbal and spatial WM) fitted the data well and was therefore selected. Notably, a bi-factor model distinguishing between modalities, but also including a common WM factor, presented with a very good fit, but was less parsimonious. Subsequently, we tested the predictive power of the verbal and spatial WM factors on fluid and crystallized intelligence. Results indicated that the shared contribution of WM explained the largest portion of variance of fluid intelligence, with verbal and spatial WM independently explaining a residual portion of the variance. Concerning crystallized intelligence, however, verbal WM explained the largest portion of the variance, with the joint contribution of verbal and spatial WM explaining the residual part. The distinction between verbal and spatial WM could be important in clinical settings (e.g., children with atypical development might struggle selectively on some WM components) and in school settings (e.g., verbal and spatial WM might be differently implicated in mathematical achievement).

The Relationship between Executive Functions, Working Memory, and Intelligence in Kindergarten Children

Executive functions (EF), working memory (WM), and intelligence are closely associated, but distinct constructs. What underlies the associations between these constructs, especially in childhood, is not well understood. In this pre-registered study, along with the traditional aggregate accuracy and RT-based measures of EF, we investigated post-error slowing (PES) in EF as a manifestation of metacognitive processes (i.e., monitoring and cognitive control) in relation to WM and intelligence. Thereby, we aimed to elucidate whether these metacognitive processes may be one underlying component to explain the associations between these constructs. We tested kindergarten children (M_age = 6.4 years, SD_age = 0.3) in an EF, WM (verbal and visuospatial), and fluid (non-verbal) intelligence task. We found significant associations of mainly the inhibition component of EF with fluid intelligence and verbal WM, and between verbal WM and intelligence. No significant associations emerged between the PES in EF and intelligence or WM. These results suggest that in the kindergarten age, inhibition rather than monitoring and cognitive control might be the underlying component that explains the associations between EF, WM, and intelligence.

The Contribution of Visual and Auditory Working Memory and Non-Verbal IQ to Motor Multisensory Processing in Elementary School Children

Although cognitive abilities have been shown to facilitate multisensory processing in adults, the development of cognitive abilities such as working memory and intelligence, and their relationship to multisensory motor reaction times (MRTs), has not been well investigated in children. Thus, the aim of the current study was to explore the contribution of age-related cognitive abilities in elementary school-age children (n = 75) aged 5-10 years, to multisensory MRTs in response to auditory, visual, and audiovisual stimuli, and a visuomotor eye-hand co-ordination processing task. Cognitive performance was measured on classical working memory tasks such as forward and backward visual and auditory digit spans, and the Raven's Coloured Progressive Matrices (RCPM test of nonverbal intelligence). Bayesian Analysis revealed decisive evidence for age-group differences across grades on visual digit span tasks and RCPM scores but not on auditory digit span tasks. The results also showed decisive evidence for the relationship between performance on more complex visually based tasks, such as difficult items of the RCPM and visual digit span, and multisensory MRT tasks. Bayesian regression analysis demonstrated that visual WM digit span tasks together with nonverbal IQ were the strongest unique predictors of multisensory processing. This suggests that the capacity of visual memory rather than auditory processing abilities becomes the most important cognitive predictor of multisensory MRTs, and potentially contributes to the expected age-related increase in cognitive abilities and multisensory motor processing.

Effects of working memory training on cognitive and academic abilities in typically developing school-age children

Process-based working memory (WM) training in typically developing children usually leads to short- and long-term improvements on untrained WM tasks. However, results are mixed regarding far transfer to academic and cognitive abilities. Moreover, there is a lack of studies jointly evaluating the different types of transfer, using an adequate design and considering motivational factors. In addition, evidence is needed about how pre-training performance is related to individual differences in training-induced transfer. Therefore, this study aimed to implement and evaluate the efficacy of a computerized process-based WM training in typically developing school-age children. Near and far transfer effects were evaluated both immediately after training and after 6 months, as well as individual differences in training-induced transfer. The sample was composed of 89 typically developing children aged 9-10 years (M = 9.52, SD = 0.30), who were randomized to a WM training group or an active control group. They were evaluated at pre-training, post-training, and follow-up phases with measures of visuospatial and verbal WM, reading comprehension, math computation, and fluid intelligence. Results showed that the training group significantly improved performance in verbal WM and fluid intelligence compared to the active control group, immediately after training and after 6 months. Trained children with lower initial performance in verbal WM or fluid intelligence showed greater transfer gains. No group differences were found in motivational factors. Findings of this study suggest that process-based WM training may promote transfer to cognitive abilities and lead to compensation effects of individual differences in typically developing school-age children.

What components of working memory are associated with children's reading skills?

Working memory (WM) is a potentially important factor related to the development of and performance in reading skills. This study examined the differential relations between two components of the WM system (i.e., storage, processing) and reading. Latent variables were created based on data from 1900 children (1146 children in preschool-second grade and 754 children in third-fifth grade) recruited for a larger study concerning the development of reading comprehension. Results indicated that a general-specific model of WM was a good fit to the data and effectively isolated the variance unique to WM-processing from that of WM-storage. Using the general-specific model, relations between the components of WM and reading (e.g., reading comprehension, decoding) and reading-related (e.g., oral language, phonological awareness, nonverbal IQ) outcomes were examined. In contrast with previous studies that have suggested WM is consistently associated with reading comprehension, our findings indicate that both aspects of WM (i.e., storage, processing) operate primarily indirectly through foundational reading-related skills. In sum, the WM system is not specifically associated with reading comprehension as most of the effects of WM-processing are indirect via the effects on foundational reading-related skills.

The contributions of working memory domains and processes to early mathematical knowledge between preschool and first grade

Working Memory (WM) plays a crucial role in supporting children's mathematical learning. However, there is no consensus on the relative contributions of different WM domains (i.e., verbal, visuo-spatial, and numerical-verbal) and processes (i.e., low-control and high-control) to mathematical performance, specifically before and after the onset of formal education. This cross-sectional study examined the relations between WM domains and processes and early mathematical knowledge, comparing a group of children in the second year of preschool (N = 66) to a group of first graders (N = 110). Results of multigroup path analysis showed that whereas visuo-spatial low-control WM significantly predicted early mathematical knowledge only among preschoolers, verbal low-control WM was a significant predictor only among first graders. Instead, the contribution of visuo-spatial high-control WM emerged as significant for both age groups, as well as that of numerical-verbal WM, although the latter to a greater extent among preschoolers. These findings provide new insights into the WM domains and processes most involved in early mathematical knowledge at different developmental stages, with potential implications for the implementation of age-appropriate training interventions targeting specific WM skills before and after the onset of formal education.

Phonological working memory and central executive function differ in children with typical development and dyslexia

The primary purpose of this study was to compare the working memory performance of monolingual English-speaking second^- grade children with dyslexia (N = 82) to second-grade children with typical development (N = 167). Prior to making group comparisons, it is important to demonstrate invariance between working memory models in both groups or between-group comparisons would not be valid. Thus, we completed invariance testing using a model of working memory that had been validated for children with typical development (Gray et al., 2017) to see if it was valid for children with dyslexia. We tested three types of invariance: configural (does the model test the same constructs?), metric (are the factor loadings equivalent?), and scalar (are the item intercepts the same?). Group comparisons favoured the children with typical development across all three working memory factors. However, differences in the Focus-of-Attention/Visuospatial factor could be explained by group differences in non-verbal intelligence and language skills. In contrast, differences in the Phonological and Central Executive working memory factors remained, even after accounting for non-verbal intelligence and language. Results highlight the need for researchers and educators to attend not only to the phonological aspects of working memory in children with dyslexia, but also to central executive function.

Explaining the high working memory capacity of gifted children: Contributions of processing skills and executive control

Intellectually gifted children tend to demonstrate especially high working memory capacity, an ability that holds a critical role in intellectual functioning. What could explain the differences in working memory performance between intellectually gifted and nongifted children? We investigated this issue by measuring working memory capacity with complex spans in a sample of 55 gifted and 55 nongifted children. Based on prior studies, we expected the higher working memory capacity of intellectually gifted children to be driven by more effective executive control, as measured using the Attention Network Test. The findings confirmed that intellectually gifted children had higher working memory capacity than typical children, as well as more effective executive attention. Surprisingly, however, working memory differences between groups were not mediated by differences in executive attention. Instead, it appears that gifted children resolve problems faster in the processing phase of the working memory task, which leaves them more time to refresh to-be-remembered items. This faster problem solving speed mediated their advantage in working memory capacity. Importantly, this effect was specific to speed on complex problems: low-level processing speed, as measured with the Attention Network Test, did not contribute to the higher working memory capacity of gifted children.

No evidence for a core deficit in developmental dyscalculia or mathematical learning disabilities

BACKGROUND

Two hypotheses were tested regarding the characteristics of children with mathematical learning disabilities (MLD): (a) that children with MLD would have a 'core deficit' in basic number processing skills; and (b) that children with MLD would be at the end of a developmental continuum and have impairments in many cognitive skills.

METHODS

From a large sample (N = 1,303) of typically developing children, we selected a group definable as having MLD. The children were given measures of basic number processing and domain-general constructs. Differences between the observed sample and a simulated population were estimated using Cohen's d and Bayes factors. Receiver operating characteristic curves were plotted, and the area under the curve was computed to ascertain the diagnostic power of measures.

RESULTS

Results suggest that the differences between the MLD and control group can be defined along with general characteristics of the population rather than assuming single or multiple 'core deficits'. None of the measures of interest exceeded the diagnostic power that could be derived via simulation from the dimensional characteristics of the general population.

CONCLUSIONS

There is no evidence for core deficit(s) in MLD. We suggest that future research should focus on representative samples of typical populations and on carefully tested clinical samples confirming to the criteria of international diagnostic manuals. Clinical diagnoses require that MLD is persistent and resistant to intervention, so studies would deliver results less exposed to measurement fluctuations. Uniform diagnostic criteria would also allow for the easy cross-study comparison of samples overcoming a serious limitation of the current literature.

Pragmatic Language in Children and Adolescents With Autism Spectrum Disorder: Do Theory of Mind and Executive Functions Have a Mediating Role?

Pragmatic language (PL) is defined as the ability to use language effectively in communicative exchanges. Previous findings showed that deficits in PL are a core characteristic of the communicative profile of individuals with autism spectrum disorder (ASD). While different lines of research have revealed a close link between PL and theory of mind (ToM), and between PL and executive functions (EFs), to our knowledge, few studies have explored the relationship between these three domains in children with ASD, and their results have been contradictory. The present study thus aimed to contribute to our understanding of PL in children with ASD and to analyze the underlying mediating role of ToM and EFs. PL is a complex and multifaceted construct. In the present study, we focused on two specific aspects, such as the comprehension of nonliteral language, and the ability to make inferences. After testing 143 participants (73 with ASD), our results confirmed that impairments in PL are a crucial feature of the ASD profile. Children with ASD were also more impaired than their typically developing peers in both ToM and EFs. When the mediating role of ToM and EFs on PL was considered, it emerged that only ToM contributed significantly to the relationship between group and PL. We discussed the potential importance of interventions not focused exclusively on PL, but also involving ToM. LAY SUMMARY: In everyday life, we use pragmatic language to interact successfully with others. Individuals with autism experience significant difficulty in pragmatic language, showing consequent impairments in communication. This study compared the comprehension of nonliteral language, and the ability to make inferences of children with autism and children with typical development, focusing on the role of social and cognitive abilities. Children with autism had difficulties in pragmatic language compared to children with typical development. In addition, the capacity to consider the perspective, intentions and beliefs of other people contributed significantly to the pragmatic language. Autism Res 2021, 14: 932-945. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

Electrophysiological correlates of the Categorization Working Memory Span task in older adults

Older adults typically show poor performance in tasks assessing working memory (WM), a crucial cognitive mechanism. The present study examined the electrophysiological correlates of a classic complex WM task often used in studies involving older adults, the Categorization Working Memory Span task (CWMS), by means of event-related potentials. Thirty-five healthy, right-handed older adults (64-75 years) were presented the CWMS task while a 38-channel EEG was measured, and the N1, P1, and word recognition potential (RP) were analyzed on four regions of interest (ROIs) of 5 electrodes each. Additionally, late positive components (P200 and P300) were analyzed in midline ROIs of 3 electrodes each. Participants also executed an n-back task (2-back condition) and an objective performance-based task (the Ability to solve Problems in Everyday life [APE]). At a behavioral level, significant correlations were found between the CWMS, the 2-back, and the APE tests. At a physiological level, N1 and word RP showed greater bilateral amplitude in posterior electrodes, but the better the CWMS and the 2-back performance, the greater the RP amplitude on posterior left sites. The CWMS task induced a clear P200 component, but its amplitude was not correlated with participants' behavioral performance. Altogether, notwithstanding that the bilateral RP pattern elicited by the CWMS is a clear marker of WM processing in older adults, better elderly performers on this complex WM test showed greater left hemisphere dominance to the automatic word RP.

Working memory predictors of mathematics across the middle primary school years

BACKGROUND

Work surrounding the relationship between visuospatial working memory (WM) and mathematics performance is gaining significant traction as a result of a focus on improving academic attainment.

AIMS

This study examined the relative contributions of verbal and visuospatial simple and complex WM measures to mathematics in primary school children aged 6-10 years.

SAMPLE

A sample of 111 children in years 2-5 were assessed (M_age  = 100.06 months, SD = 14.47).

METHOD

Children were tested individually on all memory measures, followed by a separate mathematics testing session as a class group in the same assessment wave.

RESULTS AND CONCLUSIONS

Results revealed an age-dependent relationship, with a move towards visuospatial influence in older children. Further analyses demonstrated that backward word span and backward matrices contributed unique portions of variance of mathematics, regardless of the regression model specified. We discuss possible explanations for our preliminary findings in relation to the existing literature alongside their implications for educators and further research.

Executive functions and drawing in young children with cerebral palsy: Comparisons with typical development

There is evidence that school-aged children with cerebral palsy (CP) may present deficits in executive functions (EF) greater than would be expected considering their intellectual ability. However, no studies have focused on characterizing EF in this group at an earlier critical period - the preschool years. Furthermore, and given evidence from typically-developing (TD) children, deficits in EF are associated with potential detrimental effects on social and educational development - which can include drawing. Our aim was to compare preschool children with CP, matched in chronological age and intellectual ability with a group of TD children, regarding their executive functioning and drawing abilities. In addition, we examined the relationships between these variables in each of the groups. Twenty-eight children were evaluated in executive functions and drawing tasks. Differences were found in some aspects of cognitive flexibility and inhibitory control, but not in working memory. Additionally, the quality of the drawings was significantly poorer in the CP group. In the TD group, there was an association between greater inhibitory control (but not cognitive flexibility or working memory) and drawing quality. In the CP group, although non-significant, medium-sized correlations were observed between drawing and several aspects of executive functioning. Overall, our results suggest more similarities than differences in the executive functioning of children with CP (and preserved cognitive ability) and TD children. However, there were still important between-group differences in their drawing abilities. There was also a distinct pattern of associations between drawing and executive functions in the clinical group.

Response suppression, strategy application, and working memory in the prediction of academic performance and classroom misbehavior: A neuropsychological approach

BACKGROUND

Neurological illness can produce a disorganization of behavior, including verbal disinhibition, despite apparent preserved intelligence. Neuropsychological tests of such behavioral control mechanisms may predict real-world performance of healthy people, such as success or misbehavior in educational contexts.

METHOD

In two separate studies, we examined how the Hayling Test of verbal response suppression predicts grades and classroom misbehavior.

RESULTS

Verbal suppression errors and spontaneous strategy use were significant predictors of undergraduate grades. Using a modified version of the Hayling Test designed to reduce strategic responding with high school students (mean age 16), higher grades were predicted by shorter response suppression latencies and better working memory scores, and classroom misbehavior was predicted by lower working memory scores.

CONCLUSION

Verbal response suppression and spontaneous strategy use, both closely linked to disorganized behavior in neuropsychological patients, predict academic achievement but seem unrelated to classroom misbehavior, which is associated with weakness in working memory.

Are children with developmental dyslexia all the same? A cluster analysis with more than 300 cases

Reading is vital to every aspect of modern life, exacerbated by reliance of the internet, email, and social media on the written medium. Developmental dyslexia (DD) characterizes a disorder in which the core deficit involves reading. Traditionally, DD is thought to be associated with a phonological impairment. However, recent evidence has begun to suggest that the reading impairment in some individuals is provoked by a visual processing deficit. In this paper, we present WISC-IV data from more than 300 Italian children with a diagnosis of DD to investigate the manifestation of phonological and visual subtypes. Our results indicate the existence of two clusters of children with DD. In one cluster, the deficit was more pronounced in the phonological component, while both clusters were impaired in visual processing. These data indicate that DD may be an umbrella term that encompasses different profiles. From a theoretical perspective, our results demonstrate that dyslexia cannot be explained in terms of an isolated phonological deficit alone; visual impairment plays a crucial role. Moreover, general rather than specific accounts of DD are discussed.

Working memory, negative affect and personal assets: How do they relate to mathematics and reading literacy?

Introduction

Research has recently focused on the relationships between working memory, negative affect (e.g., general anxiety, depressive symptoms) and personal assets (e.g., self-concept, academic and competence dimensions, and ego-resiliency), and their influence on mathematics and reading literacy. Although these variables have been amply explored, previous research has usually considered each of these aspects in isolation.

Method

In the present study, 143 schoolchildren in sixth to eighth grade were tested on general anxiety, depressive symptoms, working memory, self-concept (academic and competence scales), ego-resiliency, and mathematics and reading literacy.

Results

Variance partitioning showed that all predictors, i.e., working memory, negative affect (i.e., general anxiety and depressive symptoms), and personal assets (i.e., self-concept, academic and competence dimensions, and ego-resiliency) explained a unique and shared portion of the variance in mathematics and reading literacy.

Conclusions

Our findings point to the importance of investigating the relationship between these factors. Underlying implications and directions for future research are discussed.

Working Memory Structure in Atypical Development: HIV-infected and HIV-exposed, Uninfected School Beginners

Not much is known about the structure of working memory in atypical development. We undertook a detailed comparison of the functional organization of working memory in HIV-infected (n = 95; M_age = 7.42 years), and HIV-exposed (n = 86; M_age = 7.36 years) children, together with an uninfected, unexposed typically developing comparison group (n = 92; M_age = 7.05 years). Participants were in their first year of formal education. Within-group comparisons of five models showed that a four-factor model with separate verbal and visuospatial storage and processing accounted for the typically developing group, while working memory was structurally undifferentiated in the HIV-affected groups.

Variability in the Precision of Children's Spatial Working Memory

Cognitive modeling studies in adults have established that visual working memory (WM) capacity depends on the representational precision, as well as its variability from moment to moment. By contrast, visuospatial WM performance in children has been typically indexed by response accuracy—a binary measure that provides less information about precision with which items are stored. Here, we aimed at identifying whether and how children’s WM performance depends on the spatial precision and its variability over time in real-world contexts. Using smartphones, 110 Grade 3 and Grade 4 students performed a spatial WM updating task three times a day in school and at home for four weeks. Measures of spatial precision (i.e., Euclidean distance between presented and reported location) were used for hierarchical modeling to estimate variability of spatial precision across different time scales. Results demonstrated considerable within-person variability in spatial precision across items within trials, from trial to trial and from occasion to occasion within days and from day to day. In particular, item-to-item variability was systematically increased with memory load and lowered with higher grade. Further, children with higher precision variability across items scored lower in measures of fluid intelligence. These findings emphasize the important role of transient changes in spatial precision for the development of WM.

Visuospatial and Verbal Short-Term Memory Correlates of Vocabulary Ability in Preschool Children

BACKGROUND

Recent studies indicate that school-age children's patterns of performance on measures of verbal and visuospatial short-term memory (STM) and working memory (WM) differ across types of neurodevelopmental disorders. Because these disorders are often characterized by early language delay, administering STM and WM tests to toddlers could improve prediction of neurodevelopmental outcomes. Toddler-appropriate verbal, but not visuospatial, STM and WM tasks are available. A toddler-appropriate visuospatial STM test is introduced.

METHOD

Tests of verbal STM, visuospatial STM, expressive vocabulary, and receptive vocabulary were administered to 92 English-speaking children aged 2-5 years.

RESULTS

Mean test scores did not differ for boys and girls. Visuospatial and verbal STM scores were not significantly correlated when age was partialed out. Age, visuospatial STM scores, and verbal STM scores accounted for unique variance in expressive (51%, 3%, and 4%, respectively) and receptive vocabulary scores (53%, 5%, and 2%, respectively) in multiple regression analyses.

CONCLUSION

Replication studies, a fuller test battery comprising visuospatial and verbal STM and WM tests, and a general intelligence test are required before exploring the usefulness of these STM tests for predicting longitudinal outcomes. The lack of an association between the STM tests suggests that the instruments have face validity and test independent STM skills.

Intelligence and Verbal Short-Term Memory/Working Memory: Their Interrelationships from Childhood to Young Adulthood and Their Impact on Academic Achievement

Although recent developmental studies exploring the predictive power of intelligence and working memory (WM) for educational achievement in children have provided evidence for the importance of both variables, findings concerning the relative impact of IQ and WM on achievement have been inconsistent. Whereas IQ has been identified as the major predictor variable in a few studies, results from several other developmental investigations suggest that WM may be the stronger predictor of academic achievement. In the present study, data from the Munich Longitudinal Study on the Genesis of Individual Competencies (LOGIC) were used to explore this issue further. The secondary data analysis included data from about 200 participants whose IQ and WM was first assessed at the age of six and repeatedly measured until the ages of 18 and 23. Measures of reading, spelling, and math were also repeatedly assessed for this age range. Both regression analyses based on observed variables and latent variable structural equation modeling (SEM) were carried out to explore whether the predictive power of IQ and WM would differ as a function of time point of measurement (i.e., early vs. late assessment). As a main result of various regression analyses, IQ and WM turned out to be reliable predictors of academic achievement, both in early and later developmental stages, when previous domain knowledge was not included as additional predictor. The latter variable accounted for most of the variance in more comprehensive regression models, reducing the impact of both IQ and WM considerably. Findings from SEM analyses basically confirmed this outcome, indicating IQ impacts on educational achievement in the early phase, and illustrating the strong additional impact of previous domain knowledge on achievement at later stages of development.

Effect of Working Memory Updating Training on Retrieving Symptoms of Children With Learning Disabilities

Working memory (WM) deficiency is a primary reason for the poor academic performance of children with learning disabilities (LDs). Studies have shown that the WM of typical children could be improved through training, and WM training contributes to improving their fluid intelligence and academic achievement. However, few studies have investigated WM training for children with LDs, and results have been inconsistent. The present study examined the long-term effects of WM updating training and whether it can mitigate LD symptoms. Fifty-four children with LDs were recruited and divided randomly into a training or control group. The training group underwent adaptive running WM training for 20 days. Before and after training, the 2 groups completed a 2-back task, a digit span task (forward and backward), Raven's Standard Progressive Matrices test, and a scholastic attainment test (Chinese and math). The tests were repeated 6 months later. The results showed that, as compared with the controls, the training group exhibited significant improvements in the digit backward span task, 2-back task, and Raven's Standard Progressive Matrices. The math scores of the training group improved significantly by 6 months after the training. The results of this study suggest that WM updating training could mitigate the cognitive deficits of LDs and improve the WM capacity, fluid intelligence, and math scores of children with LDs. Moreover, the training effects could be maintained for at least 6 months.

Short-Term Storage and Executive Working Memory Processing Predict Fluid Intelligence in Primary School Children

Working memory (WM) includes short-term storage and executive processing of information. WM has been suggested to be one of the key concepts to explain individual differences in fluid intelligence (Gf). However, only a few studies have investigated the association of the two different aspects of WM in relation to Gf. Furthermore, even fewer studies have included children. Therefore, we first investigated the inter-relations between the WM aspects (verbal and visual-spatial storage, verbal and visual-spatial executive processing). Second, we explored the relation between a general WM factor and Gf. Third, we analyzed the relations between the different WM aspects and Gf while we controlled for common variance among all WM tasks. Nine- to 11-year olds had to solve simple and complex span tasks. Correlations and structural equation modeling techniques were used to examine these relations. Most inter-relations among simple and complex spans were found to be substantial and positive. The general WM factor was related to Gf. Furthermore, after controlling for common variance among all WM tasks, individual differences in verbal storage, visual-spatial storage and verbal processing still uniquely related to Gf. Visual-spatial processing, however, was not related to Gf. Results are discussed in terms of underlying mechanisms.

Changing relations among cognitive abilities across development: implications for measurement and research

OBJECTIVE

The constructs of intelligence and executive function (EF) are commonly used in neuropsychological, cognitive, and developmental research, and in the context of clinical assessment. Yet, we have a limited understanding of the changing age-related associations among these cognitive constructs and the implications for measurement and research. The objectives of this study were to compare hypothetical models using intellectual abilities (non-age corrected scores of intelligence or IQ) and experimental measures of EF and to better understand the role of age in determining the associations between these cognitive abilities at two different periods of development. We also incorporated prediction of ADHD-related difficulties.

METHOD

We examined intellectual abilities and EF in a typically developing child sample (N = 250) and young-adult sample (N = 329). We used confirmatory factor analysis to estimate models for each developmental period: a one-factor model of general cognitive ability and a two-factor model of intelligence and EF. ADHD-related difficulties were regressed on the factors from each model.

RESULTS

Age was more strongly related to all cognitive abilities in the child sample than in the young-adult sample. In the factor analytic models, higher amounts of cognitive test score variance were explained by both models in the child sample than in the young-adult sample. Further, in the child sample, the general cognitive ability factor (combining intellectual abilities and EF) was a significant predictor of ADHD-related difficulties, but the separate intellectual ability and EF factors were not.

CONCLUSIONS

Variables highly associated with age (such as intellectual ability and EF) should not be statistically controlled when assessing cognitive constructs especially in child samples when there is rapid change in cognitive abilities.

The Structure of Working Memory in Young Children and Its Relation to Intelligence

This study investigated the structure of working memory in young school-age children by testing the fit of three competing theoretical models using a wide variety of tasks. The best fitting models were then used to assess the relationship between working memory and nonverbal measures of fluid reasoning (Gf) and visual processing (Gv) intelligence. One hundred sixty-eight English-speaking 7-9 year olds with typical development, from three states, participated. Results showed that Cowan's three-factor embedded processes model fit the data slightly better than Baddeley and Hitch's (1974) three-factor model (specified according to Baddeley, 1986) and decisively better than Baddeley's (2000) four-factor model that included an episodic buffer. The focus of attention factor in Cowan's model was a significant predictor of Gf and Gv. The results suggest that the focus of attention, rather than storage, drives the relationship between working memory, Gf, and Gv in young school-age children. Our results do not rule out the Baddeley and Hitch model, but they place constraints on both it and Cowan's model. A common attentional component is needed for feature binding, running digit span, and visual short-term memory tasks; phonological storage is separate, as is a component of central executive processing involved in task manipulation. The results contribute to a zeitgeist in which working memory models are coming together on common ground (cf. Cowan, Saults, & Blume, 2014; Hu, Allen, Baddeley, & Hitch, 2016).

Performance on tasks of visuospatial memory and ability: A cross-sectional study in 330 adolescents aged 11 to 20

Cognitive functions mature at different points in time between birth and adulthood. Of these functions, visuospatial skills, such as spatial memory and part-to-whole organization, have often been tested in children and adults but have been less frequently evaluated during adolescence. We studied visuospatial memory and ability during this critical developmental period, as well as the correlation between these abilities, in a large group of 330 participants (aged 11 to 20 years, 55% male). To assess visuospatial memory, the participants were asked to memorize and reproduce sequences of random locations within a grid using a computer. Visuospatial ability was tested using a variation of the Design Organization Test (DOT). In this paper-and-pencil test, the participants had one minute to reproduce as many visual patterns as possible using a numerical code. On the memory task, compared with younger participants, older participants correctly reproduced more locations overall and longer sequences of locations, made fewer mistakes and needed less time to reproduce the sequences. In the visuospatial ability task, the number of correctly reproduced patterns increased with age. We show that both visuospatial memory and ability improve significantly throughout adolescence and that performance on both tasks is significantly correlated.

The Contributions of Memory and Vocabulary to Non-Verbal Ability Scores in Adolescents with Intellectual Disability

It is usually assumed that performance on non-verbal intelligence tests reflects visual cognitive processing and that aspects of working memory (WM) will be involved. However, the unique contribution of memory to non-verbal scores is not clear, nor is the unique contribution of vocabulary. Thus, we aimed to investigate these contributions. Non-verbal test scores for 17 individuals with intellectual disability (ID) and 39 children with typical development (TD) of similar mental age were compared to determine the unique contribution of visual and verbal short-term memory (STM) and WM and the additional variance contributed by vocabulary scores. No significant group differences were found in the non-verbal test scores or receptive vocabulary scores, but there was a significant difference in expressive vocabulary. Regression analyses indicate that for the TD group STM and WM (both visual and verbal) contributed similar variance to the non-verbal scores. For the ID group, visual STM and verbal WM contributed most of the variance to the non-verbal test scores. The addition of vocabulary scores to the model contributed greater variance for both groups. More unique variance was contributed by vocabulary than memory for the TD group, whereas for the ID group memory contributed more than vocabulary. Visual and auditory memory and vocabulary contributed significantly to solving visual non-verbal problems for both the TD group and the ID group. However, for each group, there were different weightings of these variables. Our findings indicate that for individuals with TD, vocabulary is the major factor in solving non-verbal problems, not memory, whereas for adolescents with ID, visual STM, and verbal WM are more influential than vocabulary, suggesting different pathways to achieve solutions to non-verbal problems.

Heterogeneity in ADHD: Neurocognitive predictors of peer, family, and academic functioning

Childhood attention-deficit/hyperactivity disorder (ADHD) is associated with impairments in peer, family, and academic functioning. Although impairment is required for diagnosis, children with ADHD vary significantly in the areas in which they demonstrate clinically significant impairment. However, relatively little is known about the mechanisms and processes underlying these individual differences. The current study examined neurocognitive predictors of heterogeneity in peer, family, and academic functioning in a well-defined sample of 44 children with ADHD aged 8-13 years (M = 10.31, SD = 1.42; 31 boys, 13 girls; 81% Caucasian). Reliable change analysis indicated that 98% of the sample demonstrated objectively-defined impairment on at least one assessed outcome measure; 65% were impaired in two or all three areas of functioning. ADHD children with quantifiable deficits in academic success and family functioning performed worse on tests of working memory (d = 0.68 to 1.09), whereas children with impaired parent-reported social functioning demonstrated slower processing speed (d = 0.53). Dimensional analyses identified additional predictors of peer, family, and academic functioning. Working memory abilities were associated with individual differences in all three functional domains, processing speed predicted social functioning, and inhibitory control predicted family functioning. These results add to a growing literature implicating neurocognitive abilities not only in explaining behavioral differences between ADHD and non-ADHD groups, but also in the substantial heterogeneity in ecologically-valid functional outcomes associated with the disorder.

Math anxiety and developmental dyscalculia: A study on working memory processes

INTRODUCTION

Although many children encounter difficulties in arithmetic, the underlying cognitive and emotive factors are still not fully understood. This study examined verbal and visuospatial short-term memory (STM) and working memory (WM) performance in children with developmental dyscalculia (DD) and high mathematics anxiety (MA) compared with typically developing (TD) children.

METHOD

Groups were matched on reading comprehension performance and IQ as well as on general anxiety. We aimed to test whether children with DD and MA were differently impaired in verbal and visuospatial STM and WM. Children were individually tested with four computerized tasks: two STM tasks (forward verbal and visuospatial recall) and two WM tasks (backward verbal and visuospatial recall).

RESULTS

Relative to children with TD, those with DD did not show impairments on the forward or backward verbal tasks, but showed specific impairments in the visuospatial WM task. In contrast, children with MA were particularly impaired in the verbal WM task.

CONCLUSIONS

Knowing the underlying cognitive processes that differentiate why children with DD and MA fail in math could have both educational and clinical implications.

Magnitude Representation and Working Memory Updating in Children With Arithmetic and Reading Comprehension Disabilities

It has been argued that children with learning disabilities (LD) encounter severe problems in working memory (WM) tasks, especially when they need to update information stored in their WM. It is not clear, however, to what extent this is due to a generally poor updating ability or to a difficulty specific to the domain to be processed. To examine this issue, two groups of children with arithmetic or reading comprehension LD and a group of typically developing children (9 to 10 years old) were assessed using two updating tasks requiring to select the smallest numbers or objects presented. The results showed that children with an arithmetic disability failed in a number updating task, but not in the object updating task. The opposite was true for the group with poor reading comprehension, whose performance was worse in the object than in the number updating task. It may be concluded that the problem of WM updating in children with LD is also due to a poor representation of the material to be updated. In addition, our findings suggest that the mental representation of the size of objects relates to the semantic representation of the objects' properties and differs from the quantitative representation of numbers.

Cognitive benefits of last night's sleep: daily variations in children's sleep behavior are related to working memory fluctuations

BACKGROUND

Recent studies have suggested substantial fluctuations of cognitive performance in adults both across and within days, but very little is known about such fluctuations in children. Children's sleep behavior might have an important influence on their daily cognitive resources, but so far this has not been investigated in terms of naturally occurring within-person variations in children's everyday lives.

METHODS

In an ambulatory assessment study, 110 elementary school children (8-11 years old) completed sleep items and working memory tasks on smartphones several times per day in school and at home for 4 weeks. Parents provided general information about the children and their sleep habits.

RESULTS

We identified substantial fluctuations in the children's daily cognitive performance, self-reported nightly sleep quality, time in bed, and daytime tiredness. All three facets were predictive of performance fluctuations in children's school and daily life. Sleep quality and time in bed were predictive of performance in the morning, and afternoon performance was related to current tiredness. The children with a lower average performance level showed a higher within-person coupling between morning performance and sleep quality.

CONCLUSIONS

Our findings contribute important insights regarding a potential source of performance fluctuations in children. The effect of varying cognitive resources should be investigated further because it might impact children's daily social, emotional, and learning-related functioning. Theories about children's cognitive and educational development should consider fluctuations on micro-longitudinal scales (e.g., day-to-day) to identify possible mechanisms behind long-term changes.