Abstract: Patients with combat-related posttraumatic stress disorder (PTSD) clinically demonstrate alterations in memory, including nightmares, flashbacks, intrusive memories, and amnesia for war experiences. In addition, descriptions from all wars of this century document alterations in memory occurring in combat veterans during or after the stress of battle. These include forgetting one's name or identity and forgetting events that had just taken place during the previous battle (1, 2), as well as gaps in memory that continue to recur for many years after the war (3). Servicemen who had been prisoners of war during the Korean conflict were found to have an impairment in short-term verbal memory, as measured by the logical memory component of the Wechsler Memory Scale, in comparison with veterans of the Korean war who did not have a history of imprisonment (4). We also found deficits in short-term verbal memory, as measured by the logical memory component of the Wechsler Memory Scale, in Vietnam combat veterans with combat-related PTSD in comparison with healthy subjects who were matched for age, years of education, and alcohol abuse (5). Several lines of evidence suggest a relation between stress and damage to the hippocampus (6). The hippocampus and the adjacent perirhinal, parahippocampal, and entorhinal cortex play an important role in short-term memory (7). Studies in humans have shown that reductions in hippocampal volume secondary to either neurosurgery (8) or the pathophysiological effects of epilepsy (9) are associated with deficits in short-term memory as measured by the Wechsler Memory Scale. Monkeys exposed to the extreme stress of improper caging have shown increased glucocorticoid release as well as damage to the CA2 and CA3 subfields of the hippocampus (10). Studies in a variety of animal species suggest that direct glucocorticoid exposure results in a loss of neurons and a decrease in dendritic branching in the hippocampus (11, 12) with associated deficits in memory function (13). The mechanism of action of glucocorticoid toxicity is probably through an increase in the vulnerability of neurons to the toxicity of excitatory amino acids (14–16). Studies using computed tomography in human subjects who are exposed to high levels of glucocorticoids secondary to glucocorticoid steroid therapy (17, 18) or who have affective disorders (also felt to be related to stress) (19) have shown changes in brain structure, including ventricular enlargement and widening of the cortical sulci. Magnetic resonance imaging (MRI) studies in patients with affective disorders have shown a smaller right hippocampal volume (20) and temporal lobe volume (21) in bipolar disorder and abnormalities of the hippocampus, including alterations in T1 (22), but no change in hippocampal volume (23) in major depression. One MRI study (24) found a relation between deficits in short-term memory and smaller hippocampal volume, as well as higher plasma cortisol levels and smaller hippocampal volume, in patients with Cushing's disease. Stress in both healthy human subjects (25) and soldiers undergoing random artillery bombardment (26) results in an increase in urinary cortisol, suggesting the possibility that exposure to the extreme stress of combat may be associated with damage to the hippocampus. The purpose of this study was to use MRI to measure the volume of the hippocampus and comparison brain structures in patients with PTSD and in matched comparison subjects. We hypothesized that PTSD would be associated with smaller hippocampal volume in relation to that of the comparison subjects. We also hypothesized that smaller hippocampal volume would be associated with deficits in short-term verbal memory in patients with PTSD.

Abstract: Two experiments using the materials of the Revised Speech Perception in Noise (SPIN-R) Test [Bilger et al., J. Speech Hear. Res. 27, 32-48 (1984)] were conducted to investigate age-related differences in the identification and the recall of sentence-final words heard in a babble background. In experiment 1, the level of the babble was varied to determine psychometric functions (percent correct word identification as a function of S/N ratio) for presbycusics, old adults with near-normal hearing, and young normal-hearing adults, when the sentence-final words were either predictable (high context) or unpredictable (low context). Differences between the psychometric functions for high- and low-context conditions were used to show that both groups of old listeners derived more benefit from supportive context than did young listeners. In experiment 2, a working memory task [Daneman and Carpenter, J. Verb. Learn. Verb. Behav. 19, 450-466 (1980)] was added to the SPIN task for young and old adults. Specifically, after listening to and identifying the sentence-final words for a block of n sentences, the subjects were asked to recall the last n words that they had identified. Old subjects recalled fewer of the items they had perceived than did young subjects in all S/N conditions, even though there was no difference in the recall ability of the two age groups when sentences were read. Furthermore, the number of items recalled by both age groups was reduced in adverse S/N conditions. The resutls were interpreted as supporting a processing model in which reallocable processing resources are used to support auditory processing when listening becomes difficult either because of noise, or because of age-related deterioration in the auditory system. Because of this reallocation, these resources are unavailable to more central cognitive processes such as the storage and retrieval functions of working memory, so that "upstream" processing of auditory information is adversely affected.

Abstract: This article reports findings on the use of a partly auditory and partly visual mode of presentation for geometry worked examples. The logic was based on the split-attention effect and the effect of presentation modality on working memory. The split-attention effect occurs when students must split their attention between multiple sources of information, which results in a heavy cognitive load. Presentation-modality effects suggest that working memory has partially independent processors for handling visual and auditory material. Effective working memory may be increased by presenting material in a mixed rather than a unitary mode. If so, the negative consequences of split attention in geometry might be ameliorated by presenting geometry statements in auditory, rather than visual, form. The results of 6 experiments supported this hypothesis.

Abstract: The very limited capacity of short-term or working memory is one of the most prominent features of human cognition. Most studies have stressed delimiting the upper bounds of this memory in memorization tasks rather than the performance of everyday tasks. We designed a series of experiments to test the use of short-term memory in the course of a natural hand-eye task where subjects have the freedom to choose their own task parameters. In this case subjects choose not to operate at the maximum capacity of short-term memory but instead seek to minimize its use. In particular, reducing the instantaneous memory required to perform the task can be done by serializing the task with eye movements. These eye movements allow subjects to postpone the gathering of task-relevant information until just before it is required. The reluctance to use short-term memory can be explained if such memory is expensive to use with respect to the cost of the serializing strategy.

Abstract: An implication of the hypothesis that failures of inhibition contribution to adult age differences in working memory (Hasher & Zacks, 1988) is that statistical control of measures of inhibition should reduce the age-related effects on working memory. This implication was tested in a study in which interference measures from three variants of a Stroop task served as the measures of inhibition. Although the age-related variance in measures of working memory was substantially reduced after control of the interference measures, the degree of attenuation was at least as large when speed measures from other tasks were controlled. Furthermore, additional analysis revealed that speed measures from tasks requiring oral, written, and keypress responses shared large proportions of their age-related variance. It was suggested that age-related influences on specific processes, such as inhibition, cannot be accurately assessed unless the contributions of more general age-related influences are taken into consideration.

Abstract: Phonological awareness was hypothesized to be composed of at least 3 component skills- IQ, verbal short-term memory, and speech perception. In addition, 4 linguistic manipulations within 3 phonological awareness tasks were theorized to affect item difficulties. Multiple measures of IQ, verbal short-term memory, speech perception, and phonological awareness were administered to 136 3rd and 4th graders. Application of structural equation modeling revealed that IQ, speech perception, and verbal short-term memory each contributed unique variance to the phonological awareness construct. All 4 experimental linguistic manipulations influenced phonological awareness item difficulties as well. Results underscore the importance of speech perception for phonological awareness

Abstract: This study investigates whether phonological working memory is associated with spoken language development in preschool children. Assessments were made of speech corpora taken from 3-year old child...

Abstract: The hypothesis that a growth in working memory capacity could explain the observed development of theory of mind in preschoolers was tested. Fifty-four 3- to 5-year-olds were administered: two false belief tasks as measures of theory of mind development; two “false” photograph tasks parallel to typical false belief tasks, but involving nonmental representations; the Peabody Picture Vocabulary Test -Revised (PPVT-R); and two working memory capacity measures (backward digit span, BDS, and forward digit span, FDS). A multiple linear regression analysis revealed that BDS significantly predicted performance on both the false belief and false photograph tasks with age and PPVT-R score controlled, but that FDS did not, suggesting that growth in central executive capacity is important in determining children's success or failure on false belief tasks, but that articulatory loop capacity is not. It is concluded that, in general, the findings are consistent with the working memory hypothesis, although subs...

Abstract: Performance on a test of serial memory for the spatial position of a sequence of dots showed similarities to typical results from the serial recall of verbal material: a marked increase in error with increasing list length, a modest rise in error as retention interval increased, and bow-shaped serial position curves. This task was susceptible to interference from both a spatial task (rote tapping) and a verbal task (mouthed articulatory suppression) and also from the presence of irrelevant speech. Effects were comparable to those found with a serial verbal task that was generally similar in demand characteristics to the spatial task. As a generalization, disruption of the serial recall of visuospatial material was more marked if the interference conditions involved a changing sequence of actions or materials, but not if a single event (tap, mouthed utterance, or sound) was repeated.

Abstract: This paper considers working memory capacity, critically examining the hypothesis that counting span (the ability to count arrays of objects and store count totals) reflects a trade-off in resources available for processing and short-term storage Previous evidence interpreted as favouring this hypothesis has confounded task difficulty with counting time Experiment 1 validated a manipulation of the attentional demands of counting in which target objects were differentiated from non-targets by either a single feature (colour) or a feature conjunction (a combination of line orientations) The results confirmed that the two presentations involved qualitatively different attentional loads Experiment 2 used these displays to compare counting span for children aged 6 to 11, both with and without an adjustment of target numerosity to control for differences in processing time At all ages, span was lower when counting took longer, but there was no difference between feature and conjunction arrays once counting time was accounted for These results argue against a resource trade-off interpretation of counting span Rather, they support a hypothesis of resource-switching among children, implying that counting span acts as a measure of time-based forgetting

Abstract: Memory is worse for items that take longer to pronounce, even when the items are equated for frequency, number of syllables, and number of phonemes. Current explanations of the word-length effect rely on a time-based decay process within the articulatory loop structure in working memory. Using an extension of Nairne's (1990) feature model, we demonstrate that the approximately linear relationship between span and pronunciation rate can be observed in a model that does not use the concept of decay. Moreover, the feature model also correctly predicts the effects of modality, phonological similarity, articulatory suppression, and serial position on memory for items of different lengths. We argue that word-length effects do not offer sufficient justification for including time-based decay components in theories of memory.

Abstract: The present study examined the phonological memory capacity, rate of articulation, phonological-encoding, and perceptual-processing abilities of 13 well-defined, specifically language-impaired (SLI) children and 13 younger, language-matched normal (NL) children. The results of a nonsense word repetition task showed that SLI children repeated significantly fewer multisyllabic nonsense words than their NL peers. However, SLI and NL children were found to have comparable articulation rates, even when producing the longest nonsense word stimuli. Both SLI and NL children showed sensitivity to the phonological similarity effect, indicating that SLI children had intact phonological-encoding abilities. The results of a nonsense word discrimination task revealed that SLI children had greater difficulty perceptually processing 4-syllable nonsense words. Taken together, these findings were interpreted to be consistent with Gathercole and Baddeley's (1990) claim that SLI children have reduced phonological storage capacity. However, the capacity deficit account may require revision to include the possibility that the phonological storage deficit of some SLI children may have a perceptual basis (i.e., difficulty with processes related to item identification).

Abstract: Short-term memory or working memory has been proposed as a cognitive structure contributing to time estimation. Thus, in a previous experiment, retrieving a stored item during a temporalinterval production lengthened the interval in proportion to the number of items in the memory set. In the present study, this issue was analyzed further by testing whether the proportional lengthening is induced by the load itself (i.e., the number of items) or by comparing the probe with memorized items. In a first experiment, a memory set was maintained during a temporal production, and the comparison of the probe with memorized items was postponed until the end of time production. Varying the number of items in the memory set had no effect on temporal intervals produced during its retention, suggesting that mental comparison was the source of the lengthening of time intervals. In succeeding experiments, tasks requiring processing in working memory but involving no memory load were combined with temporal production. In Experiment 2, increasing the number of syllables in a rhyme-judgment task proportionally lengthened temporal intervals that were produced simultaneously. In Experiment 3, increasing the amount of mental rotation in a task involving visuospatial processing also lengthened simultaneous temporal production. This interference between processing in working memory and time estimation suggests that working memory, defined as a work space for active processing of current information, contributes to time estimation.

Abstract: The present study was designed to investigate verbal and spatial short-term memory abilities in persons with Down's syndrome (DS) and intellectual disability (ID) of different aetiology. For this purpose, we compared performances of DS (n = 15; mean mental age = 5.2 years; SD = 1.2 years; mean chronological age = 16.6 years; SD = 2.9 years) and ID subjects (n = 14; mean mental age = 5.8 years; SD = 2.1 years; mean chronological age = 16.4 years; SD = 2.5 years) with those of normally developed subjects matched for mental age (n = 24) on tasks of forward and backward immediate recall of verbal and spatial sequences. Our results are discussed in the light of the Working Memory model developed by Baddeley (1986, 1990). Altogether, our data documents a deficit of verbal and spatial backward spans in persons with DS. The deficit seems to be specific for this particular aetiology group, confirming the hypothesis that ID is not a uniform condition, characterized by an undifferentiated delay of the cognitive development, but rather that it is characterized by a deficit in a complex cognitive system in which some cognitive abilities can be disrupted more than others (Detterman 1987; Vicari et al. 1992).

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

Abstract: Serial recall was studied in children with language impairment and two groups of normally achieving controls: a group matched for age and a younger group matched for reading and memory capacity. Pa...

Abstract: Factor analysis was conducted on attention, information processing, verbal and visual memory scores of 112 patients. Factor structure did not vary as a function of age. The Expanded Paired Associates Test, Verbal Selective Reminding Test, Continuous Recognition Memory Test, and Continuous Visual Memory Test defined a general memory factor. The PASAT, WMS Mental Control, and WAIS-R Digit Span defined an attention/information processing factor. Immediate Visual Reproduction (VR) loaded primarily on visual/nonverbal intelligence, whereas delayed VR loaded primarily with the memory factor. The Trail Making Test, Part B was more closely associated with visual/nonverbal intelligence than with attention/information processing. Serial Digit Learning was more closely associated with attention/information processing than with general memory.

Abstract: This study evaluated the effectiveness of a 9-week memory notebook treatment for closed-head-injured (CHI) participants with documented memory deficits. Eight participants who had sustained a severe CHI more than 2 years earlier were allocated to receive either notebook training or supportive therapy. Memory outcome indicators, which differed in sensitivity to detect everyday memory failures (EMFs), were administered before treatment, immediately after treatment, and at a 6-month follow-up. At posttreatment, the notebook training group reported significantly fewer observed EMFs on a daily checklist measure than the supportive therapy group. Although in the same direction, this finding no longer reached significance at follow-up. No significant treatment effects were found for the laboratory-based memory measures at posttreatment or follow-up. Although the present results are to be considered preliminary because of the small sample size, they suggest that notebook training has the potential to help individuals compensate for everyday memory problems and that the methods used to measure training efficacy are important.

Abstract: This article reports the results of digit-span tests that were administered to 314 children who are blind The results showed that gender, first language, and educational setting had no effect on t

Abstract: The relations among assessments of working memory (WM) and a range of complex cognitive abilities were examined. In 2 experiments participants completed 2 WM tasks designed to assess verbal and nonverbal WM, as well as assessments of verbal intelligence, nonverbal intelligence, and academic achievement. Verbal WM had no relationship with nonverbal intelligence, whereas nonverbal WM had no relationship with verbal intelligence and academic achievement. A reanalysis of P. C. Kyllonen & R. E. Christal (1990, Experiment 1) is reported in which multiple indicators of WM were used to identify verbal and nonverbal WM factors; both of these WM factors were heavily saturated with a second-order factor, g (61% and 69%, respectively). Convergent and discriminant validation of the multidimensionality of WM was found in the patterns of correlations among the first-order Working Memory, General Knowledge, and Speed factors

Abstract: While many studies point to a positive relationship between phonological skills and reading in English, little is known about these relationships for children learning to read in Arabic. Arabic orthography is considered deep if it is not vowelized but shallow if it is vowelized. The aim of this study was to examine the relationships among reading ability, phonological, semantic, orthographic and syntactic skills in Arabic. The participants were 143 Arab children, aged 8‐11, in Arab villages of central Israel. They were administered working memory, visual, oral close, phonological, word recognition, spelling, orthographic, and word attack tests. The results showed that word recognition test was highly correlated with phonological skills, semantic processing, syntactic knowledge and short‐term memory. Poor readers showed a significant lag in the development of these skills, the problems being most significant at phonological and semantic levels and less so at the visual levels. The similarities and...

Abstract: Three groups of children with dyslexia, with mean age 8, 13 and 17 years, together with three groups of normally achieving children matched for age and IQ with the dyslexic groups, undertook tests of sound categorization and phoneme deletion. The design allowed comparison not only across chronological age but also across reading age. The children with dyslexia performed significantly worse even than their reading age controls on both tasks. Indeed, overall performance of the 17 year old children with dyslexia was closest, but inferior, to that of the 8 year old controls. Since the sound categorization task was designed to minimize working memory load, the results extend previous findings on the phonological awareness deficits in dyslexia by dissociating the deficit from memory load and by showing that it persists at least into late adolescence.

Abstract: This study investigated whether individual differences in working memory (WM) span are associated with different WM management strategies during the reading of expository text. In Experiment 1, probe questions were presented on line during reading to determine whether thematic information was maintained in WM throughout comprehension. The data indicated that readers across the range of WM span maintained thematic information in WM throughout the reading of a given passage. In Experiment 2, sentence reading times and accuracy for both topic and detail questions were measured in two conditions: when topic sentences were present and when topic sentences were absent. Subjects performed similarly across the range of WM span in the topic-present condition, but lower span subjects performed more poorly on detail questions in the topic-absent condition. In Experiment 3, the topic-present condition of the second experiment was replicated, except that subjects expected to receive questions about details only. Thematic processing and retention of topic and detail information all increased with span. Taken together, these results suggest that, for more difficult text processing tasks, high- and low-span subjects adopt different WM management strategies and these strategies influence what is learned from reading the text.

Abstract: The mechanisms underlying performance on the Star Counting Test (SCT) and its nomothetic span were investigated along with the relationships between working memory capacity, fluid intelligence (Gf), speed, and school achievement. The SCT is an attention test for children that requires the alternation of forward and backward counting. The test is based on A. D. Baddeley and G. J. Hitch's (1974) model of working memory in conjunction with D. A. Norman and T. Shallice's (1986) theory of central executive functioning. Tests were administered to 1,122 boys and 1100 girls in 4th grade from 111 Dutch schools. The SCT required flexible alternation, counting speed, and sustained effort. Factor analysis showed that the SCT forms one factor with other indicators of working memory capacity. There was also a strong association between working memory capacity and Gf. The two clearly differ, however, in their relation to speed. Attention and intelligence are important determinants of school achievement (Fraser, Walberg, Welch, & Hattie, 1987; Horn & Packard, 1985; Rowe, 1991). During this century, correlational studies have provided considerable insight into the structure of intelligence (e.g., Carroll, 1993). More recently, experimental researchers have identified some of the mechanisms underlying performance on specific intelligence tests (Butterfield, Nielsen, Tangen, & Richardson, 1985; Carpenter, Just, & Shell, 1990; Geary & Widaman, 1992; Steraberg, 1985). In contrast, in the field of attention there is still a gap between what Cronbach (1957) called the "two disciplines of psychology" (p. 671), the experimental and the correlational approach. In the present study, both approaches were used to investigate the construct validity of the Star Counting Test (SCT), an attention test for children (de Jong & Das-Smaal, 1990). First, the construct representation of the test, including its dimensionality and the mechanisms that are involved in test performance, was determined. Next, we examined the nomothetic span of the SCT by considering its relationships with working memory, intelligence, speed, and school achievement. In what follows, we first describe the theoretical background of the test, and subsequently, we consider its construct representation and nomothetic span.