Examination stress and components of working memory

Previous research suggests that stress can influence a broad range of memory functions. In this study we investigated the effect of a naturalistic stressor, examination stress, on working memory in young adults. In order to accomplish this aim, participants were tested on psychological and hormonal measures of stress and on Digit Span, once during a low stress period and once during a high stress period. The high examination stress condition was associated with an increase in cortisol and subjective impressions of stress. Although Digits Forward performance did not vary with examination stress, Digits Backward performance improved. These findings suggest that mild increases in stress are associated with improvement in the manipulation component of working memory. However, no correlations were found between working memory and either cortisol or psychological stress. Thus the mechanism by which mild naturalistic stressors improve the manipulation component of working memory needs further investigation.     

Working memory training and transfer in older adults

There has been a great deal of interest, both privately and commercially, in using working memory training exercises to improve general cognitive function. However, many of the laboratory findings for older adults, a group in which this training is of utmost interest, are discouraging due to the lack of transfer to other tasks and skills. Importantly, improvements in everyday functioning remain largely unexamined in relation to WM training. We trained working memory in older adults using a task that encourages transfer in young adults (Chein & Morrison, 2010). We tested transfer to measures of working memory (e.g., Reading Span), everyday cognitive functioning [the Test of Everyday Attention (TEA) and the California Verbal Learning Test (CVLT)], and other tasks of interest. Relative to controls, trained participants showed transfer improvements in Reading Span and the number of repetitions on the CVLT. Training group participants were also significantly more likely to self-report improvements in everyday attention. Our findings support the use of ecological tasks as a measure of transfer in an older adult population.     

工作记忆在归纳推理能力老化中的作用

目的：考查工作记忆系统中与目标保持密切相关的成分——工作记忆容量、转换和抑制功能在归纳推理能力老化中的作用。方法：招募年轻和老年被试共117名,接受图形推理测验、数字工作记忆广度测验、任务转换和Stroop测验。结果：工作记忆容量在归纳推理能力老化中起到显著的中介作用,而转换功能的中介作用则未达到显著。结论：增龄导致了工作记忆容量的衰退,进而造成了归纳推理能力的老化。     

The backward span of the Corsi Block-Tapping Task and its association with the WAIS-III Digit Span

The Corsi Block-Tapping Task measures visuospatial short-term and working memory, but a standardized backward condition is lacking. The authors present a standardized backward procedure that was examined in 246 healthy older adults (ages 50 to 92), comparing the results with the Digit Span subtest of the Wechsler Adult Intelligence Scale--Third Edition. Principal component analysis resulted in a two-factor model, dissociating a verbal and a spatial working-memory factor. Also the Corsi backward is not more difficult than the Corsi forward, in contrast to the Digit Span backward that is more difficult than the Digit Span forward. This may suggest that the Corsi Block-Tapping Task backward task relies on processing within working-memory's slave systems, whereas the Digit Span backward also relies on the central executive component of working memory. Finally, regression-based normative data and cutoff scores for older adults are presented for use in clinical practice.     

Effects of Age,Domain, and Processing Demands on Memory Span: Evidence for Differential Decline

Analysis of cross-sectional data from the normative sample of the Wechsler Memory Scale - Third Edition (WMS-III) revealed different patterns of age-related differences in memory span measures depending on the type of memory item, processing demands, and the age of the older adult group. Regression of memory span on age revealed that the slope for Spatial Span raw scores was significantly more negative than the slope for Digit Span raw scores. There was no significant difference, however, either between the slopes for forward and backward Digit Span or between the slopes for forward and backward Spatial Span. Regression of Letter-Number Sequencing raw scores on age showed a distinctive, curvilinear pattern. Taken together, the present findings suggest that at least two mechanisms are involved in age-related differences in memory span. One mechanism, associated with a relatively linear decrease in memory span as a function of age, may differentially affect the storage of different types of information (e.g., sequences of digits vs. spatial locations). The other mechanism, evidenced by the curvilinear trend in Letter-Number Sequencing scores, may be tentatively attributed to a decline in executive aspects of working memory that becomes increasingly pronounced with age.     

工作记忆容量的差异对第二语言句法歧义句加工的影响

采用眼动技术, 以句子阅读过程中, 句子不同区段的首次注视时间作为句子即时性加工的指标, 回扫次数和总的注视时间作为句子非即时加工的指标, 考察了非熟练的汉-英双语者, 工作记忆容量的差异对第二语言(英语)暂时句法歧义句加工的影响。结果显示: 高工作记忆容量的被试, 在句子不同区段的首次注视时间和总的注视时间均短于低工作记忆容量的被试; 高、低工作记忆容量被试的回扫模式相似。研究结果表明, 对于非熟练的汉-英双语者, 工作记忆容量的差异既影响英语句法歧义句即时性的加工, 也影响非即时性的加工, 即工作记忆容量的差异既影响英语句法歧义句初始的句法加工过程, 也影响句法的重新分析过程。研究结果在一定程度上支持工作记忆容量限制的理论。     

L’Empan de lecture comme épreuve mesurant la capacité de mémoire de travail : normes basées sur une population francophone de 775 adultes jeunes et âgés

The present article describes the development, administration, scoring procedure and sampling of a Reading Span Task assessing the controlled attention component of working memory. This task was standardized on a French speaking population of 775 young and older adults. The task holds satisfactory reliability, validity and sensibility and thus appears to be a reliable tool to measure working memory capacity. The norms were established as a function of participants’ age, gender and socio-cultural level.     

Children's working memory: investigating performance limitations in complex span tasks

Three experiments investigated the roles of resource-sharing and intrinsic memory demands in complex working memory span performance in 7- and 9-year-olds. In Experiment 1, the processing complexity of arithmetic operations was varied under conditions in which processing times were equivalent. Memory span did not differ as a function of processing complexity. In Experiment 2, complex memory span was assessed under three conditions designed to vary both processing and intrinsic storage demands: mental arithmetic (significant attentional demands-requires storage), odd/even judgments (significant attentional demands-no storage required), and articulatory suppression (minimal attentional demands--no storage required). The highest memory spans were found in the articulatory suppression task. Span was at an intermediate level with arithmetic processing and was lowest for processing involving odd/even judgments. This difference in memory span for processing tasks involving arithmetic processing and odd/even judgments was eliminated in Experiment 3 when the pacing requirements of the arithmetic and odd/even processing tasks were equated. The results are consistent with the view that complex memory span performance is disrupted by processing activities that divert attentional resources from storage.     

Working memory, text comprehension, and propositional reasoning: a new Semantic Anaphora WM test

The aim of this study was to present a new working memory test following the line of work started by García-Madruga et al. (2007) and to examine its relation to reading comprehension and propositional reasoning measures. In that study we designed a new working memory span test--based on Daneman & Carpenter's (1980) Reading Span Test (RST)--in which the processing task called for an inferential decision--to resolve a pronominal anaphora based on Morpho-Syntactic cues and had people recall the result of this inference. In the current study, besides the RST and the Morpho-Syntactic Anaphora test, we presented a new Semantic Anaphora measure. In order to check the validity of this new Working Memory (WM) task, we used the same reasoning task used in the previous study as well as a new reading comprehension test. The results show the tight relationship amongst working memory, reading comprehension and reasoning, and confirm the validity of the new WM measure.     

Are sluggish cognitive tempo symptoms associated with executive functioning in preschoolers?

The aim of this study is to investigate whether sluggish cognitive tempo (SCT) symptoms are associated with neurocognitive task performance and ratings of real-world executive functioning (EF) in preschoolers at risk for attention-deficit/hyperactivity disorder (ADHD). The associations between parent- and teacher-rated SCT symptoms and neuropsychological task performance and ratings of EF in 61 4-year-old preschool children (51 boys, 10 girls) with self-regulation difficulties were examined, with regression analyses controlling for the effects of ADHD inattention symptoms. In the study sample, higher teacher-rated SCT symptoms are significantly associated with poorer performance on tasks of visual-perceptual abilities, auditory and visual attention, sustained and selective attention, inhibitory control, pre-numerical/numerical concepts, and slower processing speed, but SCT symptoms are not significantly associated with working memory, attention shifting or cognitive flexibility when controlling for ADHD inattention. Higher parent-rated SCT symptoms are significantly associated with visual-perceptual abilities. ADHD inattention symptoms are more strongly associated than SCT with daily life EF ratings; neither parent- nor teacher-rated SCT symptoms are significantly associated with daily life ratings of inhibition, working memory, or planning/organization after controlling for ADHD inattention. This study suggests that SCT symptoms contribute to EF deficits at least on neurocognitive tasks assessing visual-perceptual/spatial abilities, attention to detail and processing speed, as observed in this sample of young children at risk for ADHD, and may be an important intervention target.     

The contributions of memory and attention processes to cognitive abilities

In two experiments, the contributions of memory and attention processes to the cognitive abilities of reasoning and perceptual speed were investigated. Two measures of speed of information retrieval from long-term and short-term memory (Posner paradigm, Sternberg paradigm) and two attention measures (continuous attention test, attention switching test) were included in the first experiment (N = 220). The memory tests led to correlations with the measures of cognitive abilities, whereas the attention test did not. The same tests as well as one additional memory test and one attention test (working memory test, test of covert orientation) were administered in the second experiment (N = 116). Again, the memory tests led to the larger correlations with the measures of cognitive abilities. Two components were obtained in components analysis, of which the first was characterized by high loadings of the memory tests and the second by high loadings of the attention tests. Only the memory component contributed to the prediction of cognitive abilities.     

Working memory and inhibitory control across the life span: Intrusion errors in the Reading Span Test

The aim of this study was to examine to what extent inhibitory control and working memory capacity are related across the life span. Intrusion errors committed by children and younger and older adults were investigated in two versions of the Reading Span Test. In Experiment 1, a mixed Reading Span Test with items of various list lengths was administered. Older adults and children recalled fewer correct words and produced more intrusions than did young adults. Also, age-related differences were found in the type of intrusions committed. In Experiment 2, an adaptive Reading Span Test was administered, in which the list length of items was adapted to each individual’s working memory capacity. Age groups differed neither on correct recall nor on the rate of intrusions, but they differed on the type of intrusions. Altogether, these findings indicate that the availability of attentional resources influences the efficiency of inhibition across the life span.     

The Contributions of Memory and Attention Processes to Cognitive Abilities

In two experiments, the contributions of memory and attention processes to the cognitive abilities of reasoning and perceptual speed were investigated. Two measures of speed of information retrieval from long-term and short-term memory (Posner paradigm, Sternberg paradigm) and two attention measures (continuous attention test, attention switching test) were included in the first experiment (N = 220). The memory tests led to correlations with the measures of cognitive abilities, whereas the attention test did not. The same tests as well as one additional memory test and one attention test (working memory test, test of covert orientation) were administered in the second experiment (N = 116). Again, the memory tests led to the larger correlations with the measures of cognitive abilities. Two components were obtained in components analysis, of which the first was characterized by high loadings of the memory tests and the second by high loadings of the attention tests. Only the memory component contributed to the prediction of cognitive abilities.     

The construct validity of the stanford-binet 5 measures of working memory

This study examines the validity of the measures of verbal and nonverbal working memory on the Stanford-Binet Fifth Edition (SB5). The validity evidence included Rasch-based, criterion-referenced item mapping, correlations with other clinical measures of memory, and prediction of reading and mathematics scores. The item mapping clearly demonstrates a parallel between increasing item difficulty and a progression of item characteristics that placed increasing demands on verbal and nonverbal working memory. The higher correlations of the SB5 verbal and nonverbal working memory subtests with other measures of verbal and nonverbal memory, respectively, and lower correlations with nonverbal and verbal memory measures, respectively, clearly show convergent and divergent validity. The higher correlations between SB5 verbal working memory and reading skills and between SB5 nonverbal memory and mathematics skills are consistent with past research.     

Transition to success on the model room task: the importance of improvements in working memory

Previous work has shown that children under age 3 often perform very poorly on the model room task, in which they are asked to find a hidden toy based on its location in a scale model. One prominent theory for their failure is that they lack the ability to understand the model as both a physical object and as a symbolic representation of the larger room. A hypothesized additional component is that they need to overcome weak, competing representations of where the object was on a previous trial, and where it is in the present trial, in order to succeed in their search. Children aged 33–39 months were tested on the model room task, as well as on measures of cognitive inhibitory control, cognitive flexibility, and working memory. Results showed that performance on the model room task was not predicted by measures of inhibitory control or cognitive flexibility, but was predicted by performance on the Delayed Recognition Span Test (DRST), a measure of working memory. These findings lend support to the theory of competing representations and demonstrate the necessity of updating and maintaining strong representations in working memory to succeed in the search task.     

A comparison of laboratory and clinical working memory tests and their prediction of fluid intelligence

The working memory (WM) construct is conceptualized similarly across domains of psychology, yet the methods used to measure WM function vary widely. The present study examined the relationship between WM measures used in the laboratory and those used in applied settings. A large sample of undergraduates completed three laboratory-based WM measures (operation span, listening span, and n-back), as well as the WM subtests from the Wechsler Adult Intelligence Scale-III and the Wechsler Memory Scale-III. Performance on all of the WM subtests of the clinical batteries shared positive correlations with the lab measures; however, the Arithmetic and Spatial Span subtests shared lower correlations than the other WM tests. Factor analyses revealed that a factor comprising scores from the three lab WM measures and the clinical subtest, Letter-Number Sequencing (LNS), provided the best measurement of WM. Additionally, a latent variable approach was taken using fluid intelligence as a criterion construct to further discriminate between the WM tests. The results revealed that the lab measures, along with the LNS task, were the best predictors of fluid abilities.     

Time constraints and resource sharing in adults' working memory spans

This article presents a new model that accounts for working memory spans in adults, the time-based resource-sharing model. The model assumes that both components (i.e., processing and maintenance) of the main working memory tasks require attention and that memory traces decay as soon as attention is switched away. Because memory retrievals are constrained by a central bottleneck and thus totally capture attention, it was predicted that the maintenance of the items to be recalled depends on both the number of memory retrievals required by the intervening treatment and the time allowed to perform them. This number of retrievals:time ratio determines the cognitive load of the processing component. The authors show in 7 experiments that working memory spans vary as a function of this cognitive load.     

Working memory and behavioral inhibition in children with attention-deficit/hyperactivity disorder (ADHD): an examination of varied central executive demands,construct overlap,and task impurity

The stop-signal paradigm is the premier metric of behavioral inhibition in contemporary attention-deficit/hyperactivity disorder (ADHD) research. The stop-signal paradigm’s choice-reaction time component, however, arguably places greater demands on working memory processes (e.g., controlled-focused attention) relative to alternative inhibition metrics (i.e., go/no-go (GNG) tasks), and consequently obscures conclusions about inhibition and working memory deficits in affected children. The current study, therefore, aimed to determine whether shared variance between stop-signal behavioral inhibition and working memory performance in children with ADHD reflects overlap between the working memory and inhibition constructs or insufficient specificity of the stop-signal paradigm. Fifty-five children (8–12 years) with and without ADHD were administered established phonological (PH) and visuospatial (VS) working memory measures, as well as stop-signal and GNG tasks that vary with respect to demands on controlled-focused attention. Although working memory and GNG performance each uniquely predicted children’s inattention, stop-signal task performance was not a significant predictor of unique variance in inattention, above and beyond variance associated with working memory. Collectively, these findings suggest that performance on the stop-signal task, compared to the GNG task, is confounded by greater demands associated with working memory and consequently reflects an impure estimate of the inhibition construct.     

Selective attention is a primary determinant of the relationship between working memory and general learning ability in outbred mice

A single factor (i.e., general intelligence) can account for much of an individuals' performance across a wide variety of cognitive tests. However, despite this factor's robustness, the underlying process is still a matter of debate. To address this question, we developed a novel battery of learning tasks to assess the general learning abilities (GLAs) of mice. Using this battery, we previously reported a strong relationship between GLA and a task designed to tax working memory capacity (i.e., resistance to competing demands). Here we further explored this relationship by investigating which aspects of working memory (storage or processing) best predict GLAs in mice. We found that a component of working memory, selective attention, correlated with GLA comparably to working memory capacity. However, this relationship was not found for two other components of working memory, short-term memory capacity and duration. These results provide further evidence that variations in aspects of working memory and executive functions covary with general cognitive abilities.     

Working memory, reading, and mathematical skills in children with developmental coordination disorder

The aim of the present study was investigate the relationship between working memory and reading and mathematical skills in 55 children diagnosed with developmental coordination disorder (DCD). The findings indicate a pervasive memory deficit in all memory measures. In particular, deficits observed in visuospatial short-term and working memory tasks were significantly worse than in the verbal short-term memory ones. On the basis of these deficits, the sample was divided into high and low visuospatial memory ability groups. The low visuospatial memory group performed significantly worse on the attainment measures compared to the high visuospatial memory group, even when the contribution of IQ was taken into account. When the sample was divided into high and low verbal working memory ability groups, verbal working memory skills made a unique contribution to attainment only when verbal IQ was taken into account, but not when performance IQ was statistically controlled. It is possible that the processing demands of the working memory tasks together with the active motor component reflected in the visuospatial memory tasks and performance IQ subtest both play a crucial role in learning in children with DCD.