Storage and processing in visuo-spatial working memory

Visuo-spatial working memory has been used to account for performance in a wide range of visuo-spatial tasks, including perceptuo-motor tracking and immediate recall of visually presented patterns. However a developing body of evidence points to a fractionation of the concept into visuo-spatial processing that calls on general purpose executive resources, and a visual 'cache' memory for temporary storage in on-line cognition. Two related experiments are described which address whether processing and temporary memory draw on overlapping or on distinct resources in working memory. Experiment 1 demonstrates that participants can accurately respond to a series of targets appearing in random locations whether or not they have the additional load of retaining and subsequently recalling the appearance of each target. Memory for target appearance likewise is largely unaffected by the additional load of requiring a response to each target. Experiment 2 demonstrates similar findings when verbal labeling of the patterns is inhibited through the use of articulatory suppression. Results are interpreted as consistent with a multiple component working memory system.     

Processes of verbal memory failure in Alzheimer-type dementia

Multiple aspects of verbal learning and memory performance in mild as compared to moderate Alzheimer-type dementia (ATD) were studied with the Buschke selective reminding paradigm. Results show that (1) both groups of ATD subjects depend less on long-term memory (LTM) and more on short-term memory (STM) relative to elderly control subjects, (2) mild ATD subjects show less LTM encoding than moderate ATD subjects, (3) moderate ATD subjects retrieve a smaller portion of the items presumed to be encoded into LTM than do mild ATD subjects, and (4) high-imagery words increase LTM encoding and retrieval as compared to low-imagery words for moderate ATD subjects only. These results are explained by the inability of ATD subjects to attend to more than one component of the list-learning task, in conjunction with differences in the deployment of attention between mild and moderate ATD subjects.     

Visuo-spatial processing in working memory

This paper reports four experiments designed to develop a simple technique for the study of visuo-spatial processing within the working memory framework (Baddeley and Hitch, 1974). Experiment 1 involved the matching of successively presented random matrix patterns, as a secondary visual suppression task. This was coupled with rote rehearsal or a visual imagery mnemonic for learning lists of concrete words presented auditorily. Although memory performance with matching dropped overall, the visual mnemonic was differentially affected. Experiment 2 removed the matching decision, with visual presentation of unattended patterns. There was no overall effect of the unattended material, but use of the visual mnemonic was significantly affected. Experiment 3 replicated this result with simpler plain coloured squares as the unattended material.

In Experiment 4, for one group, the unattended material consisted of line drawings of common objects. For a second group, the lists of words for recall were presented visually, with or without unattended speech. The results suggested that unattended pictures disrupt use of a visual mnemonic, while unattended speech disrupts rote rehearsal.

These results suggest that unattended visual material has privileged access to the mechanism(s) involved in short-term visuo-spatial processing and storage. They also suggest that use of a concurrent visual matching task or of unattended visual material may provide tractable techniques for investigating this aspect of cognitive function within the context of working memory.     

Memory for internally generated words in Alzheimer-type dementia: breakdown in encoding and semantic memory

The "generation effect" is a phenomenon in which words that are generated by the subject are remembered better than words which are read. The present experiments examined this effect in patients with mild-to-moderate dementia of the Alzheimer type (DAT), healthy elderly adults, and young adults under a variety of different encoding and retrieval conditions. Experiment 1 employed an intentional learning task with multiple study/test trials using the same list of words. While both the young and elderly adults exhibited higher recall for internally generated words than read words, the DAT patients failed to demonstrate the effect even after repeated exposures to the same stimulus list. Experiment 2 replicated this same pattern of results using an incidental learning paradigm with both recall and recognition tests. Various explanations as to why the DAT patients failed to show the generation effect were discussed with particular emphasis placed on the role of semantic memory and encoding failure.     

Temporal interval production and processing in working memory

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.     

Emotion processing facilitates working memory performance

The effect of emotional stimulus content on working memory performance has been investigated with conflicting results, as both emotion-dependent facilitation and impairments are reported in the literature. To clarify this issue, 52 adult participants performed a modified visual 2-back task with highly arousing positive stimuli (sexual scenes), highly arousing negative stimuli (violent death) and low-arousal neutral stimuli. Emotional stimulus processing was found to facilitate task performance relative to that of neutral stimuli, both in regards to response accuracy and reaction times. No emotion-dependent differences in false-alarm rates were found. These results indicate that emotional information can have a facilitating effect on working memory maintenance and processing of information.     

Emotion processing facilitates working memory performance

The effect of emotional stimulus content on working memory performance has been investigated with conflicting results, as both emotion-dependent facilitation and impairments are reported in the literature. To clarify this issue, 52 adult participants performed a modified visual 2-back task with highly arousing positive stimuli (sexual scenes), highly arousing negative stimuli (violent death) and low-arousal neutral stimuli. Emotional stimulus processing was found to facilitate task performance relative to that of neutral stimuli, both in regards to response accuracy and reaction times. No emotion-dependent differences in false-alarm rates were found. These results indicate that emotional information can have a facilitating effect on working memory maintenance and processing of information.     

Motor expertise modulates movement processing in working memory

A substantial amount of literature has demonstrated individuals' tendency to code verbally a series of movements for subsequent recall. However, the mechanisms underlying movement encoding remain unclear. In this paper, I argue that sensorimotor expertise influences the involvement of motor processes to store movements in working memory. Experts in motor activities and individuals with limited motor expertise were compared in three experimental conditions assessing movement recall: (a) without suppression task, (b) with verbal suppression, and (c) with motor suppression. Athletes outperformed controls in movement recall, but the suppression tasks affected the two groups differently. Verbal suppression affected controls more than athletes, whereas the effect was reversed with motor suppression. Together, these findings suggest that controls and athletes favor different mechanisms to encode movements, either based on verbal or on motor processes, providing further evidence for a tight relationship between sensorimotor and cognitive processes.     

客体同维度特征的视觉工作记忆存储机制

客体理论认为视觉工作记忆的存储单位是客体, 人类能够把组成物体的所有特征整合成一个单元进行记忆, 不管这些特征是来自不同维度还是同一维度。然而同一维度多个特征可以被整合成客体记忆的结果只被少数研究证实, 大量研究发现同一维度的多个特征不能被整合记忆, 这形成了弱客体理论的基本观点。为了解决两大理论之间的争议, 本研究主要探究同维度特征能否被整合记忆。通过分析以往研究, 我们认为实验范式和物体意义两个因素可能是导致之前大部分研究没有发现维度内特征能够被整合记忆的原因。因此, 实验1采用回忆报告范式替代以往研究经常使用的变化觉察范式, 结果发现, 同一维度的多个特征难以被整合记忆。实验2以记忆无意义物体的特征为基线, 探究在记忆有意义物体的特征时是否可能将多个特征进行整合记忆。结果发现, 对于有意义物体的特征的记忆成绩并没有显著好于记忆无意义物体特征的成绩, 说明即使采用具有较强整合线索的有意义物体作为载体, 同一维度多个特征也难以被整合记忆。两个实验结果进一步支持了弱客体理论。     

Neuroanatomical correlates of processing in visual and visuospatial working memory

Working memory is traditionally seen as being organised in a modular way with a central executive orchestrating at least two slave systems (phonological loop and visuospatial sketch pad). Neuroanatomical correlates of the visual and visuospatial subsystems and the central executive are discussed in this article. A series of experiments are presented yielding evidence for a differentiation into active and passive processing in working memory as well as their neuroanatomical correlates in the prefrontal cortex. Data, yielding evidence for an interaction and separation of visual and visuospatial working memory are presented and discussed. Further results are presented which suggest a convergence of these two systems with increasing working memory demands. The discussed findings will give new insight in the organisation of visual and visuospatial working memory on the anatomical level.     

Emotion processing effects on interference resolution in working memory

The interaction between emotion and working memory maintenance, load, and performance has been investigated with mixed results. The effect of emotion on specific executive processes such as interference resolution, however, remains relatively unexplored. In this series of studies, we examine how emotion affects interference resolution processes within working memory by modifying the Recency-probes paradigm (Monsel, 1978) to include emotional and neutral stimuli. Reaction time differences were compared between interference and non-interference trials for neutral and emotional words (Studies 1 & 3) and pictures (Study 2). Our results indicate that trials using emotional stimuli show a relative decrease in interference compared with trials using neutral stimuli, suggesting facilitation of interference resolution in the former. Furthermore, both valence and arousal seem to interact to produce this facilitation effect. These findings suggest that emotion facilitates response selection amid interference in working memory.     

Trait anxiety,visuospatial processing,and working memory

This experiment assessed the components of Baddeley's working memory system impaired by anxiety during performance of the Corsi Blocks Test. The Corsi task was performed concurrently with different secondary tasks (i.e., articulatory suppression; counting backwards; spatial tapping; simple tapping). Results showed Corsi performance depended mainly on the central executive and visuospatial sketchpad components of working memory. Adverse effects of trait anxiety on the Corsi task were observed on the central executive but not on the phonological loop or the visuospatial sketchpad. These effects were not mediated by state anxiety. The findings indicate for the first time that trait anxiety impairs central executive functioning on a nonverbal task, and that anxiety does not impair functioning of the “slave” systems (i.e., phonological loop; visuospatial sketchpad). Theoretical implications of these findings are discussed.     

Storage of features, conjunctions and objects in visual working memory

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.     

The influence of theta transcranial alternating current stimulation (tACS) on working memory storage and processing functions

The study aimed to explore the role of the fronto-parietal brain network in working memory function—in temporary storage and manipulation of information. In a single blind sham controlled experiment 36 respondents solved different working memory tasks after theta transcranial alternating current stimulation (tACS) was applied to left frontal, left parietal and right parietal areas. Both verum tACS protocols stimulating parietal brain areas (target electrodes positioned at location P3, or P4) had a positive effect on WM storage capacity as compared with sham tACS, whereas no such influence was observed for the stimulation of the left frontal area (target electrode positioned at location F3). A second finding was that left parietal theta tACS had a more pronounced influence on backward recall than on forward recall, which was not related to task content (spatial or verbal). The influence of theta tACS on WM executive processes was most pronounced for right parietal stimulation. The results are discussed in the broad theoretical framework of the multicomponent model of working memory.     

On the law relating processing to storage in working memory

Working memory is usually defined in cognitive psychology as a system devoted to the simultaneous processing and maintenance of information. However, although many models of working memory have been put forward during the last decades, they often leave underspecified the dynamic interplay between processing and storage. Moreover, the account of their interaction proposed by the most popular A. D. Baddeley and G. Hitch's (1974) multiple-component model is contradicted by facts, leaving unresolved one of the main issues of cognitive functioning. In this article, the author derive from the time-based resource-sharing model of working memory a mathematical function relating the cognitive load involved by concurrent processing to the amount of information that can be simultaneously maintained active in working memory. A meta-analysis from several experiments testing the effects of processing on storage corroborates the parameters of the predicted function, suggesting that it properly reflects the law relating the 2 functions of working memory.     

高功能孤独症幼儿空间工作记忆的组块加工缺陷

孤独症谱系障碍者存在空间工作记忆加工缺陷,其具体受损环节尚不明确。组块是一种有效的策略性信息编码方式,是空间工作记忆的关键环节。高度结构化的刺激容易形成高水平组块,因此,刺激结构化程度对记忆效果的影响能够反映个体的组块加工能力。研究采用Sternberg空间工作记忆任务、Corsi空间广度任务,加入刺激结构化因素,考察高功能孤独症幼儿是否存在组块加工缺陷,并探讨组块加工是否直接影响到空间工作记忆容量。实验1采用Sternberg空间工作记忆任务,结果表明,ASD幼儿存在明显的组块加工缺陷。在易于组块的高结构化条件下,健康幼儿的记忆成绩明显较高,而ASD幼儿在高、低结构化条件下的记忆成绩并无显著差异。实验2采用Corsi空间广度任务,结果显示,不论高、低结构化条件,ASD幼儿的空间工作记忆容量均显著低于健康幼儿。但ASD幼儿由于存在组块加工缺陷,在高、低结构化条件下的记忆成绩差异较健康幼儿小。因此,ASD幼儿的组块能力一定程度上影响了空间工作记忆容量。此外,记忆存储器的异常可能也是ASD幼儿空间工作记忆容量不足的重要原因。研究表明,ASD幼儿的空间组块缺陷主要由于弱中央统合的认知风格,他们缺乏自上而下的组块加工动机,难以主动对刺激形成高水平组块编码,从而影响记忆效果。     

Relational processing and working memory capacity in comprehension of relative clause sentences

Previous research has indicated that the cognitive load imposed by tasks in various content domains increases with the complexity of the relational information processed. Sentence comprehension entails processing noun-verb relations to determine who did what to whom. The difficulty of object-extracted relative clause sentences might stem from the complex noun-verb relations they entail. Across three studies, participants read 16 types of object- and subject-extracted relative clause sentences at their own pace and then responded to a comprehension question for each sentence. Relational processing was assessed using a premise integration task or a Latin square task. These tasks predicted comprehension of object-relatives before and after controlling for subject-relatives. Working memory (WM) capacity was assessed using reading span or forward and backward digit span tests. WM tasks predicted comprehension of object-relatives before but not after controlling for subject-relatives. Comprehension of object-relatives relied more heavily on a domain-general capacity to process complex relations than on WM capacity.     

Speed of processing, anticipation, inhibition and working memory in bilinguals

Literature on the so-called bilingual advantage is directed towards the investigation of whether the mastering of two languages fosters cognitive skills in the non-verbal domain. The present study aimed to evaluate whether the bilingual advantage in non-verbal skills could be best defined as domain-general or domain-specific, and, in the latter case, at identifying the basic cognitive skills involved. Bilingual and monolingual participants were divided into two different age groups (children, youths) and were tested on a battery of elementary cognitive tasks which included a choice reaction time task, a go/no-go task, two working memory tasks (numbers and symbols) and an anticipation task. Bilingual and monolingual children did not differ from each other except for the anticipation task, where bilinguals were found to be faster and more accurate than monolinguals. These findings suggest that anticipation, which has received little attention to date, is an important cognitive domain which needs to be evaluated to a greater extent both in bilingual and monolingual participants.     

The role of working memory and visual processing in prototype category learning

To investigate whether working memory and visual processing have the same role or different roles in A/B and A/not A prototype category learning, the present study adopted an A/B or A/not A category learning task in control and dual conditions. The results of Experiment 1 showed that an additional dual visual working memory task rather than a dual verbal working memory task reduced accuracy of the A/B task, whereas no dual tasks influenced accuracy of the A/not A task. The results of Experiment 2 revealed that an additional dual visual processing task impaired accuracy of the A/B task, whereas the dual visual processing task did not influence accuracy of the A/not A task. These results indicate that visual working memory and visual processing play different roles in A/B and A/not A prototype category learning, and support that these two types of prototype category learning are mediated by different memory systems.