Abstract: Children's mathematical skills were considered in relation to executive functions. Using multiple measures-including the Wisconsin Card Sorting Task (WCST), dual-task performance, Stroop task, and counting span-it was found that mathematical ability was significantly correlated with all measures of executive functioning, with the exception of dual-task performance. Furthermore, regression analyses revealed that each executive function measure predicted unique variance in mathematics ability. These results are discussed in terms of a central executive with diverse functions (Shallice & Burgess, 1996) and with recent evidence from Miyake, et al. (2000) showing the unity and diversity among executive functions. It is proposed that the particular difficulties for children of lower mathematical ability are lack of inhibition and poor working memory, which result in problems with switching and evaluation of new strategies for dealing with a particular task. The practical and theoretical implications of these re...

Abstract: The current state of A.D. Baddeley and G.J. Hitch’s (1974) multicomponent working memory model is reviewed. The phonological and visuospatial subsystems have been extensively investigated, leading both to challenges over interpretation of individual phenomena and to more detailed attempts to model the processes underlying the subsystems. Analysis of the controlling central executive has proved more challenging, leading to a proposed clarification in which the executive is assumed to be a limited capacity attentional system, aided by a newly postulated fourth system, the episodic buffer. Current interest focuses most strongly on the link between working memory and long-term memory and on the processes allowing the integration of information from the component subsystems. The model has proved valuable in accounting for data from a wide range of participant groups under a rich array of task conditions. Working memory does still appear to be working. The term working memory appears to have been first proposed by Miller, Galanter, and Pribram (1960) in their classic book Plans and the Structure of Behavior. The term has subsequently been used in computational modeling approaches (Newell & Simon, 1972) and in animal learn

Abstract: Individuals with high math anxiety demonstrated smaller working memory spans, especially when assessed with a computation-based span task. This reduced working memory capacity led to a pronounced increase in reaction time and errors when mental addition was performed concurrently with a memory load task. The effects of the reduction also generalized to a working memory-intensive transformation task. Overall, the results demonstrated that an individual difference variable, math anxiety, affects on-line performance in math-related tasks and that this effect is a transitory disruption of working memory. The authors consider a possible mechanism underlying this effect--disruption of central executive processes--and suggest that individual difference variables like math anxiety deserve greater empirical attention, especially on assessments of working memory capacity and functioning.

Abstract: Working memory can be divided into separate subsystems for verbal and visual information. Although the verbal system has been well characterized, the storage capacity of visual working memory has not yet been established for simple features or for conjunctions of features. The authors demonstrate that it is possible to retain information about only 3-4 colors or orientations in visual working memory at one time. Observers are also able to retain both the color and the orientation of 3-4 objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing many individual features to be retained when distributed across a small number of objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features.

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

Abstract: The hypothesis that working memory is crucial for reducing distraction by maintaining the prioritization of relevant information was tested in neuroimaging and psychological experiments with humans. Participants performed a selective attention task that required them to ignore distractor faces while holding in working memory a sequence of digits that were in the same order (low memory load) or a different order (high memory load) on every trial. Higher memory load, associated with increased prefrontal activity, resulted in greater interference effects on behavioral performance from the distractor faces, plus increased face-related activity in the visual cortex. These findings confirm a major role for working memory in the control of visual selective attention.

Abstract: Summary Goal-directed behaviour depends on keeping relevant information in mind (working memory) and irrelevant information out of mind (behavioural inhibition or interference resolution). Prefrontal cortex is essential for working memory and for interference resolution, but it is unknown whether these two mental abilities are mediated by common or distinct prefrontal regions. To address this question, functional MRI was used to identify brain regions activated by separate manipulations of working memory load and interference within a single task (the Sternberg item recognition paradigm). Both load and interference manipulations were associated with performance decrements. Subjects were unaware of the interference manipulation. There was a high degree of overlap between the regions activated by load and interference, which included bilateral ventrolateral and dorsolateral prefrontal cortex, anterior insula, anterior cingulate and parietal cortex. Critically, no region was activated exclusively by interference. Several regions within this common network exhibited a brain–behaviour

Abstract: The authors investigated the possibility that working memory span tasks are influenced by interference and that interference contributes to the correlation between span and other measures. Younger and older adults received the span task either in the standard format or one designed to reduce the impact of interference with no impact on capacity demands. Participants then read and recalled a short prose passage. Reducing the amount of interference in the span task raised span scores, replicating previous results (C. P. May, L. Hasher, & M. J. Kane, 1999). The same interference-reducing manipulations that raised span substantially altered the relation between span and prose recall. These results suggest that span is influenced by interference, that age differences in span may be due to differences in the ability to overcome interference rather than to differences in capacity, and that interference plays an important role in the relation between span and other tasks.

Abstract: We sought to determine the course of the preclinical episodic memory deficit in Alzheimer's disease. Using data from a population-based study, we compared persons who developed Alzheimer's disease n = 15) with persons who were non-demented n = 105) 6 and 3 years prior to the diagnosis of dementia. Participants were tested on tasks assessing episodic memory free recall and recognition of words) and short-term memory digit span). The incident Alzheimer's disease cases performed more poorly than their non-demented counterparts both 3 and 6 years before diagnosis on recall and recognition. There were no group differences in either forward or backward digit span. The selective impairment of episodic memory before the diagnosis of Alzheimer's disease is consistent with the view that early changes in the hippocampal complex play an important role in the memory deficit in preclinical Alzheimer's disease. On both preclinical measurement occasions, recall and recognition made independent contributions to group classification in logistic regression analyses. However, there was no evidence for accelerated decline of episodic memory in the incident Alzheimer's disease group from 6 to 3 years before diagnosis. These results indicate that Alzheimer's disease is characterized by a long preclinical period during which episodic memory deficits are detectable. The magnitude of these deficits appears to be quite stable, at least up to 3 years before diagnosis. This may reflect the fact that those biological events that eventually result in clinically diagnosed Alzheimer's disease e.g. the appearance of amyloid plaques and neurofibrillary tangles) accumulate at a relatively slow rate.

Abstract: Measures of retrieval speed indicated that only a small subset of representations in working memory falls within the focus of attention. An n-back task, which required tracking an item 1, 2, or 3 back in a sequentially presented list, was used to examine the representation and retrieval of recent events and how control processes can be used to maintain an item in focal attention while concurrently processing new information. A speed-accuracy trade-off procedure was used to derive measures of the availability and the speed with which recent events can be accessed. Results converge with other time course studies in demonstrating that attention can be concurrently allocated only to a small number of memory representations, perhaps just 1 item. Measures of retrieval speed further demonstrate that order information is retrieved by a slow search process when an item is not maintained within focal attention.

Abstract: The effect of emotional disclosure through expressive writing on available working memory (WM) capacity was examined in 2 semester-long experiments. In the first study, 35 freshmen assigned to write about their thoughts and feelings about coming to college demonstrated larger working memory gains 7 weeks later compared with 36 writers assigned to a trivial topic. Increased use of cause and insight words was associated with greater WM improvements. In the second study, students (n = 34) who wrote about a negative personal experience enjoyed greater WM improvements and declines in intrusive thinking compared with students who wrote about a positive experience (n = 33) or a trivial topic (n = 34). The results are discussed in terms of a model grounded in cognitive and social psychological theory in which expressive writing reduces intrusive and avoidant thinking about a stressful experience, thus freeing WM resources.

Abstract: In this study, we examine the role of strategy use in working memory (WM) tasks by providing short-term memory (STM) task strategy training to participants. In Experiment 1, the participants received four sessions of training to use a story-formation (i.e., chaining) strategy. There were substantial improvements from pretest to posttest (after training) in terms of both STM and WM task performance. Experiment 2 demonstrated that WM task improvement did not occur for control participants, who were given the same amount of practice but were not provided with strategy instructions. An assessment of participants' strategy use on the STM task before training indicated that more strategic participants displayed better WM task performance and better verbal skills. These results support our hypothesis that strategy use influences performance on WM tasks.

Abstract: A.D. Baddeley, G.J. Hitch, Foreword. J. Andrade, An Introduction to Working Memory. Applied Perspectives. D.G. Pearson, Imagery and the Visuo-spatial Sketchpad. J. Andrade, The Contribution of Working Memory to Conscious Experience. A.-M. Adams, C. Willis, Language Processing and Working Memory: A Developmental Perspective. L.H. Phillips, C. Hamilton, The Working Memory Model in Adult Aging Research. C. Jarrold, Applying the Working Model to the Study of Atypical Development. R. Henson, Neural Working Memory. Theoretical Perspectives. M. Page, R. Henson, Computational Models of Short-term Memory: Modelling Serial Recall of Verbal Material. P. Lovatt, S.E. Avons, Re-evaluating the Word-length Effect. G. Ward, A Critique of the Working Memory Model. J.N. Towse, C.M.T Houston-Price, Reflections on the Concept of the Central Executive. J. May, Specifying the Central Executive May Require Complexity. Conclusion. J. Andrade, The Working Memory Model: Consensus, Controversy and Future Directions.

Abstract: In this contribution, we review an ERP experiment and an fMRI experiment which investigated the processing of German wh-questions. On the basis of the ERP results, we will discuss current models of sentence processing and resource distribution during sentence comprehension. We argue that there exists a separate cognitive or neural resource that supports syntactic working memory processes necessary for the temporary maintenance of syntactic information for the parser. In the context of wh-movement, such a memory component is necessary for establishing filler-gap dependencies. The data obtained from the fMRI experiment will be used to discuss the results of previous neuroimaging studies of sentence processing. It is claimed that syntactic working memory, rather than syntactic processing per se, is supported by Broca's Area.

Abstract: Objectives. Intrusive memories of extreme trauma can disrupt a stepwise approach to imaginal exposure. Concurrent tasks that load the visuospatial sketchpad (VSSP) of working memory reduce the vividness of recalled images. This study tested whether relief of distress from competing VSSP tasks during imaginal exposure is at the cost of impaired desensitization. Design. This study examined repeated exposure to emotive memories using 18 unselected undergraduates and a within-subjects design with three exposure conditions (Eye Movement, Visual Noise, Exposure Alone) in random, counterbalanced order. Method. At baseline, participants recalled positive and negative experiences, and rated the vividness and emotiveness of each image. A different positive and negative recollection was then used for each condition. Vividness and emotiveness were rated after each of eight exposure trials. At a post-exposure session 1 week later, participants rated each image without any concurrent task. Results. Consistent with previous research, vividness and distress during imaging were lower during Eye Movements than in Exposure Alone, with passive visual interference giving intermediate results. A reduction in emotional responses from Baseline to Post was of similar size for the three conditions. Conclusion. Visuospatial tasks may offer a temporary response aid for imaginal exposure without affecting desensitization.

Abstract: One hundred twenty-seven individuals who ranged in age from 18 to 90 years were tested on a reading span test and on measures of on-line and off-line sentence processing efficiency. Older participants had reduced working-memory spans compared with younger participants. The on-line measures were sensitive to local increases in processing load, and the off-line measures were sensitive to the syntactic complexity of the sentences. Older and younger participants showed similar effects of syntactic complexity on the on-line measures. There was some evidence that older participants were more affected than younger participants by syntactic complexity on the off-line measures. The results support the hypothesis that on-line processes involved in recognizing linguistic forms and determining the literal, preferred, discourse-coherent meaning of sentences constitute a domain of language processing that relies on its own processing resource or working-memory system.

Abstract: Recent researchers have attempted to correlate measures of working memory (WM) with measures of higher level cognitive skills and abilities focusing on the functions of this limited capacity system, i.e., processing and storage. Relationships between three span measures of the functional model of WM capacity and two measures of reading comprehension were investigated. The magnitude of the correlations found between reading comprehension and the two spans embedded in reading processing tasks was similar to that of the correlation found between a third span measure embedded in a quantitative task with reading comprehension. These results indicated that these span measures of WM capacity were independent of the nature of the concurrent processing task.

Abstract: Over the last half century, the experimental study of human memory has departed from the earlier concept of a unitary faculty, with the increase in knowledge leading to differentiation between subsystems of memory, often based on the study of neuropsychological patients. Although foreshadowed by the classic work of William James (1890), the current approach to the fractionation of memory probably began with Hebb's (1949) proposal of a distinction between short-term memory (STM), based on temporary electrical activity within the brain, and longterm memory (LTM), based on the development of more permanent neurochemical changes. He even proposed a learning mechanism, a concept that continues to be influential in neurobiological theorizing (see Burgess et al. 2001). Experimental evidence for a distinction between STM and LTM began to appear a decade later with the demonstration by Brown (1958) and Peterson & Peterson (1959) of the rapid forgetting of small amounts of material when ongoing rehearsal was prevented. They proposed that this forgetting reflected the decay of a short-term trace, a process they distinguished from long-term forgetting, which was attributed to interference among longterm memory representations. This view was resisted, with the counter claim made that all forgetting could be interpreted within a single stimulus-response association framework (Melton 1963). The question of whether shortterm forgetting reflects trace decay or interference remains unresolved (Cowan et al. 2000; Service 1998). During the 1960s, however, experimental evidence from a range of sources seemed to point increasingly strongly to the need to distinguish between STM and LTM on grounds other than type of forgetting. Neuropsychological evidence was particularly influential, with patients suffering from the classic amnesic syndrome showing grossly impaired LTM, coupled with total preservation of performance on a range of tasks associated with STM (Baddeley & Warrington 1970). Anatomically, the amnesic syndrome has most strongly been associated with damage to the hippocampus (Milner 1966), although it could result from damage to a series of structures that broadly make up the Papez circuit (see Aggleton & Pearce 2001). The STM-LTM distinction was further supported by patients showing the opposite dissociation, with STM performance impaired and LTM preserved (Shallice & Warrington 1970). By the late 1960s, a range of two-component models was being proposed, of which the most influential was that of Atkinson & Shiffrin (1968). In this model, information was assumed to come in from the environment, be processed by a short-term storage system and then fed into LTM. Probability of learning was assumed to depend on time held within the short-term store. STM was also

Abstract: Working memory (WM) declines with advancing age. Brain imaging studies indicate that ventral prefrontal cortex (PFC) is active when information is retained in WM and that dorsal PFC is further activated for retention of large amounts of information. The authors examined the effect of aging on activation in specific PFC regions during WM performance. Six younger and 6 older adults performed a task in which, on each trial, they (a) encoded a 1- or 6-letter memory set, (b) maintained these letters over 5-s. and (c) determined whether or not a probe letter was part of the memory set. Comparisons of activation between the 1- and 6-letter conditions indicated age-equivalent ventral PFC activation. Younger adults showed greater dorsal PFC activation than older adults. Older adults showed greater rostral PFC activation than younger adults. Aging may affect dorsal PFC brain regions that are important for WM executive components.

Abstract: Two experiments are reported that address theoretical assumptions as to the nature of working memory involved in working memory span tasks (Daneman & Carpenter, 1980). Experiment 1 used a version of the sentence span task, and Experiment 2 combined arithmetic verification with recall of presented words. In each experiment, working memory processing span was assessed independently of temporary storage span prior to their combination. Combined task performance under high demand for each component resulted in substantial residual performance for both task elements, particularly in Experiment 2. The results do not challenge the utility of the sentence span task as a measure of on-line cognition, but they raise concerns as to how resource might be allocated to processing and storage elements of the task within a single flexible resource pool, or between different resources of a multiple component working memory system. Although both models lack predictive power regarding resource allocation in these tasks, the multiple resource model appears to offer the better account.

Abstract: The aim of the present research was to determine whether short-term memory and working memory could be distinguished. In two studies, 7- to 13-year-olds (N = 155, N = 132) were administered tasks thought to assess short-term memory as well as tasks thought to assess working memory. Both exploratory and confirmatory factor analyses distinguished short-term memory tasks from working memory tasks. In addition, performance on working memory tasks was related to word decoding skill but performance on short-term memory tasks was not. Finally, performance on both short-term memory and working memory tasks were associated with age-related increases in processing speed. Results are discussed in relation to models of short-term and working memory.

Abstract: Barkley (1997a) proposed that the central deficit in Attention Deficit Hyperactivity Disorder (ADHD) is in behavioral inhibition, resulting in deficits both in working memory and sense of time. To ...

Abstract: Two experiments are reported in which subjects performed working memory and enumeration tasks. In the first experiment, subjects scoring low on the working memory task also performed poorly on the attention-demanding “counting” portion of the enumeration task. Yet no span differences were found for the non-attention-demanding “subitizing” portion. In Experiment 2, conjunctive and disjunctive distractors were added to the enumeration task. Although both high and low working memory span subjects were adversely affected by the addition of conjunctive distractors, the effect was much greater for the low-span subjects. Implications from these findings are that differences in working memory capacity correspond to differences in capability for controlled attention.

Abstract: We explore several alternative formal models of working memory capacity limits and of the effect of ageing on these capacity limits. Three models test variations of resource accounts, one assumes a fixed number of free slots in working memory, one is based on decay and processing speed, one attributes capacity limits to interference, and one to crosstalk between associations of content and context representations. The models are evaluated by fitting them to time–accuracy functions of 16 young and 17 old adults working on a numerical memory-updating task under varied memory-load conditions. With increasing complexity (i.e., memory load), both asymptotic accuracy and the rate of approach to the asymptote decreased. Old adults reached lower asymptotes with the more complex tasks, and had generally slower rates. The interference model and the decay model fit the individual time–accuracy functions reasonably well, whereas the other models failed to account for the data. Within the interference model, age effec...