6-9岁儿童工作记忆的发展研究

以Baddeley工作记忆模型为基础考察儿童语音环路、视觉空间模板、中央执行的发展及其与复杂广度的关系。225名6-9岁被试完成9个任务,分别测量听力广度及工作记忆三个子系统的功能。发现工作记忆各个子成分的功能在6-9岁期间发展速度不同;中央执行与语音环路和视觉空间模板的联系随年龄增长加强;结构方程模型分析发现中央执行和语音环路功能对儿童听力广度都有显著的直接影响,表明言语复杂广度任务既涉及中央执行功能也涉及语音环路的存贮功能。     

The focus of attention in working memory: Evidence from a word updating task

Three experiments examined the cognitive costs of item switching within working memory with a novel word updating task, thereby extending previous research to the field of linguistic stimuli and linguistic-graphemic updating operations. In Experiments 1 and 2 costs for switching between working memory items were evident on the word level, and they increased with an increasing word set size (Experiment 2). In contrast, a surprisingly similar switch effect on the level of letters was not affected by word set size (Experiment 2). Experiment 3 showed that this effect is not simply based on the need for re-orienting visual spatial attention. To account for the overall picture of results, a recursive model of attentional foci is proposed. Moreover, individual working memory span appears to be associated with the accuracy of item switching, but not with its speed.     

The focus of attention in working memory: evidence from a word updating task

Three experiments examined the cognitive costs of item switching within working memory with a novel word updating task, thereby extending previous research to the field of linguistic stimuli and linguistic-graphemic updating operations. In Experiments 1 and 2 costs for switching between working memory items were evident on the word level, and they increased with an increasing word set size (Experiment 2). In contrast, a surprisingly similar switch effect on the level of letters was not affected by word set size (Experiment 2). Experiment 3 showed that this effect is not simply based on the need for re-orienting visual spatial attention. To account for the overall picture of results, a recursive model of attentional foci is proposed. Moreover, individual working memory span appears to be associated with the accuracy of item switching, but not with its speed.     

Serial attention within working memory

It is proposed that people are limited to attending to just one “object” in working memory (WM) at any one time. Consequently, many cognitive tasks, and much of everyday thought, necessitate switches between WM items. The research to be presented measured the time involved in switching attention between objects in WM and sought to elaborate the processes underlying such switches. Two experiments required subjects to maintain two running counts; the order in which the counts were updated necessitated frequent switches between them. Even after intensive practice, a time cost was incurred when subjects updated the two counts in succession, relative to updating the same count twice. This time cost was interpreted as being due to a distinct switching mechanism that controls an internal focus of attention large enough for just one object (count) at a time. This internal focus of attention is a subset of WM (Cowan, 1988). Alternative visual and conceptual repetition-priming and memory retrieval explanations for the cost involved in switching between items in WM are addressed.     

Working memory capacity and the antisaccade task: individual differences in voluntary saccade control

Performance on antisaccade trials requires the inhibition of a prepotent response (i.e., don't look at the flashing cue) and the generation and execution of a correct saccade in the opposite direction. The authors attempted to further specify the role of working memory (WM) span differences in the antisaccade task. They tested high- and low-span individuals on variants of prosaccade and antisaccade trials in which an eye movement is the sole requirement. In 3 experiments, they demonstrated the importance of WM span differences in both suppression of a reflexive saccade and generation of a volitional eye movement. The results support the contention that individual differences in WM span are not exclusively due to differences in inhibition but also reflect differences in directing the focus of attention.     

The influence of complex working memory span task administration methods on prediction of higher level cognition and metacognitive control of response times

Participants between the ages of 18 and 80 were tested on a complex working memory span task that was administered either using a typical experimenter-paced method or using a method in which the processing component was presented at a fixed, limited-pace presentation rate. Path analyses revealed that even after controlling for individual differences in general processing speed, the limited-pace task predicted unique variance in episodic memory, executive functioning, and fluid intelligence, whereas the experimenter-paced task did not. For the experimenter-paced task, slower responses on the processing component of the task were associated with better recall, but only when individual differences in processing speed were controlled. These findings suggest that metacognitive control of response times affects recall from working memory span tasks, as well as the relationship between span task recall and high-level cognition. These results support resource-sharing explanations of working memory and suggest that limiting processing times using computer pacing of complex span tasks can be an effective way to efficiently measure working memory capacity.     

记忆集对注意焦点转换及其返回抑制的影响

采用记忆更新任务,实验1要求被试分别更新3个和4个记忆项目,并设置不转换、控制转换和抑制转换条件,考察记忆集对注意焦点转换及其返回抑制的影响;实验2操纵两次更新同一记忆项目之间对其它记忆项目更新的次数（2次、3次及3次以上）,在实验1基础上,考察返回抑制中项目抑制状态的消退过程.结论：随记忆集增加,转换代价增大,而返回抑制效应消失;当注意焦点对其它记忆项目更新2次时,之前被抑制项目的抑制状态可完全消退.     

Ageing and switching of the focus of attention in working memory: results from a modified N-back task.

We conducted two experiments using a modified version of the N-Back task. For younger adults, there was an abrupt increase in reaction time of about 250 ms in passing from N = 1 to N > 1, indicating a cost associated with switching of the focus of attention within working memory. Response time costs remained constant over the range N = 2 to N = 5. Accuracy declined steadily over the full range of N (Experiment 1). Focus switch costs did not interact with either working memory updating (Experiment 1), or global task switching (Experiment 2). There were no age differences in RT costs once general slowing was taken into account, but there was a larger focus-switch-related accuracy cost in older adults than in younger adults. No age sensitivity was found for either updating or global task switching. The results suggest (a) that focus switching is a cognitive primitive, distinct from task switching and updating, and (b) that focus switching shows a specific age-related deficit in the accuracy domain.     

Sources of individual differences in working memory: Contributions of strategy to capacity

Some research on attentional control in working memory has emphasized theoretical capacity differences. However, strategic behavior, which has been relatively unexplored, can also influence attentional control and its relationship to cognitive performance. In two experiments, we examined the relationship between attentional control (measured with operation span) and interference in a part-list cuing paradigm. Paradoxically, the results indicated that superior attentional control was related to increased interference. This relationship reflected the participants’ use of more complex encoding strategies, rather than superior interference control at retrieval, and was eliminated following brief encoding strategy training. The results suggest that complex span measures sometimes predict individual differences in task strategies related to interference control and that these strategies may be amenable to training. The implications for working memory research and the roles of strategies in basic memory and attention paradigms are briefly discussed.     

工作记忆中的注意焦点转换

在工作记忆中的选择性注意及注意焦点机制的基础上,从3个方面回顾了对工作记忆中注意焦点转换的研究：（1）工作记忆中的注意焦点转换的概念及其基本研究方法;（2）影响注意焦点转换代价的因素,包括提取、复述、加工、更新和记忆集大小等;（3）注意焦点转换与工作记忆各功能成分之间的关系,包括注意焦点转换与工作记忆执行功能的关系,注意焦点转换反映的存储、加工和执行功能之间的相互关系,注意焦点转换与工作记忆中资源分配的关系。最后,该文展望了未来的研究方向     

Visual selective attention is equally functional for individuals with low and high working memory capacity: Evidence from accuracy and eye movements

Selective attention and working memory capacity (WMC) are related constructs, but debate about the manner in which they are related remains active. One elegant explanation of variance in WMC is that the efficiency of filtering irrelevant information is the crucial determining factor, rather than differences in capacity per se. We examined this hypothesis by relating WMC (as measured by complex span tasks) to accuracy and eye movements during visual change detection tasks with different degrees of attentional filtering and allocation requirements. Our results did not indicate strong filtering differences between high- and low-WMC groups, and where differences were observed, they were counter to those predicted by the strongest attentional filtering hypothesis. Bayes factors indicated evidence favoring positive or null relationships between WMC and correct responses to unemphasized information, as well as between WMC and the time spent looking at unemphasized information. These findings are consistent with the hypothesis that individual differences in storage capacity, not only filtering efficiency, underlie individual differences in working memory.     

Aging and working memory inside and outside the focus of attention: dissociations of availability and accessibility

Two experiments used the N-Back task to test for age differences in working memory inside and outside the focus of attention. Manipulations of the difficulty of item-context binding (Experiment 1) and of stimulus feature binding (Experiment 2) were used to create conditions that varied in their demand on working memory, with the expectation that greater demand might increase age differences in focus-switching costs and the search rate outside the focus of attention. Results showed, however, that although age differences were evident in measures of overall speed and accuracy, and the manipulations significantly affected response times and accuracy in the expected direction, the experimental manipulations had no impact on age differences. Findings instead pointed to age-related reductions in accuracy but not speed of focus-switching and search outside the focus of attention. Thus, age-related deficits appear to involve the availability of representations in working memory, but not their accessibility.     

Aging, focus switching, and task switching in a continuous calculation task: evidence toward a new working memory control process

This study examined switching of the focus of attention in working memory in relation to global task switching in a continuous calculation task using two rules (midpoint and up-and-down) in a group of 25 younger adults and a group of 23 older adults. Age differences emerged in accuracy when participants worked on two strings simultaneously (necessitating a focus switch); focus switching did not interact with age in the response time domain. No age differences were obtained for global task switching. Ex-Gaussian decomposition showed a shift due to focus switching in all parameters, but a shift in leading edge only for task switching. The results suggest that task switching and focus switching rely on different processes, and that there is a specific age-related deficit in focus switching.     

Awareness and working memory in strategy adaptivity

To further the understanding of the mechanisms of strategy choice, in three experiments, we investigate the role of explicit awareness and working memory in strategy adaptivity. Experiment 1 provided correlational evidence that individual differences in strategy adaptivity to changing base rates are related to individual differences in awareness of those changes but appear not to be related to individual differences in working memory capacity. Experiment 2 replicated the role of awareness, and the results suggest that awareness at the time of the base-rate change, rather than afterwards, is related to increased strategy adaptivity. Experiment 3 measured working memory capacity using a different procedure and manipulated working memory load with a dual-task procedure; again, no apparent role of working memory capacity in strategy adaptivity was found. This juxtaposition of findings presents a challenge for existing models of strategy choice.     

Aging and Working Memory Inside and Outside the Focus of Attention: Dissociations of Availability and Accessibility

ABSTRACT

Two experiments used the N-Back task to test for age differences in working memory inside and outside the focus of attention. Manipulations of the difficulty of item-context binding (Experiment 1) and of stimulus feature binding (Experiment 2) were used to create conditions that varied in their demand on working memory, with the expectation that greater demand might increase age differences in focus-switching costs and the search rate outside the focus of attention. Results showed, however, that although age differences were evident in measures of overall speed and accuracy, and the manipulations significantly affected response times and accuracy in the expected direction, the experimental manipulations had no impact on age differences. Findings instead pointed to age-related reductions in accuracy but not speed of focus-switching and search outside the focus of attention. Thus, age-related deficits appear to involve the availability of representations in working memory, but not their accessibility.     

Working memory and inattentional blindness

Individual differences in working memory predict many aspects of cognitive performance, especially for tasks that demand focused attention. One negative consequence of focused attention is inattentional blindness, the failure to notice unexpected objects when attention is engaged elsewhere. Yet, the relationship between individual differences in working memory and inattentional blindness is unclear; some studies have found that higher working memory capacity is associated with greater noticing, but others have found no direct association. Given the theoretical and practical significance of such individual differences, more definitive tests are needed. In two studies with large samples, we tested the relationship between multiple working memory measures and inattentional blindness. Individual differences in working memory predicted the ability to perform an attention-demanding tracking task, but did not predict the likelihood of noticing an unexpected object present during the task. We discuss the reasons why we might not expect such individual differences in noticing and why other studies may have found them.     

Three layers of working memory: Focus-switch costs and retrieval dynamics as revealed by the N-count task

Two experiments explored the process of switching items in and out of the focus of attention using a new paradigm, the N-count task (adapted from Garavan, 1998; N varied from 1 to 4). This task yielded a focus size of one, indicated by a substantial focus-switch cost for 2-count. Additionally, the focus-switch costs in response time increased with working memory load, indicating an effortful search process occurring at a speed of about 240 ms/item. Maintaining and switching to and from a passive load did not increase the focus-switch costs or decrease memory accuracy, indicating that there is no crosstalk between passive and active items. The results support a concentric theory of working memory: a small focus at its core, a surrounding area of (at least) three readily available items referred to as the outer store, and a still wider region of passive storage, possibly more long-term memory than working memory.     

The validity of “conceptual span” as a measure of working memory capacity

Three experiments tested whether a modified version of the Clustered Conceptual Span task (H. J. Haarmann, E. J. Davelaar, & M. Usher, 2003), which ostensibly requires active maintenance of semantic representations, predicted individual differences in higher-order cognitive abilities better than short-term memory (STM) span tasks or nonsemantic versions of the "Conceptual" task did. Nonsemantic Conceptual tasks presented short word lists clustered by color, first letter, or initial vowel sound, and cued subjects to recall only 1 of 3 clusters from each list; the Semantic task clustered words by taxonomic category. The Semantic Conceptual task generally failed to predict incremental variance in either verbal abilities or general fluid intelligence beyond the other Conceptual tasks or STM span tasks. Although the Semantic task showed a stronger relation to working memory span tasks than did the nonsemantic tasks (Experiment 3), that stronger relation did not translate into strong prediction of cognitive individual differences.     

Executive control processes of working memory predict attentional blink magnitude over and above storage capacity

When two masked, to-be-attended targets are presented within approximately half a second of each other, performance on the second target (T2) suffers, relative to when the targets are presented further apart in time or when the first target (T1) can be ignored. This phenomenon is known as the attentional blink (AB). Colzato et al. (Psychon Bull Rev 14:1051–1057, 2007) used an individual differences approach to examine whether individual AB magnitude was predicted by individual differences in working memory (WM), using the operation span paradigm (OSPAN). They found that OSPAN score was inversely related to AB magnitude even when a fluid intelligence measure (Raven’s SPM) was partialled out. However, it is not clear from this study whether it was the executive control aspect of working memory, the capacity aspect of short-term memory, (or both), that related to AB magnitude. In the present study we used a variety of WM measures that required varying degrees of executive control. OSPAN was negatively related to AB magnitude with Raven’s SPM, reading comprehension, reading rate, and digit forward and backward partialled out. Backward and forward digit span did not predict AB magnitude. These results support the conclusion that a “working” executive component of WM predicts temporal limitations of selective attention beyond static STM capacity and general cognitive ability.     

Lapses in sustained attention and their relation to executive control and fluid abilities: An individual differences investigation

A latent variable analysis was conducted to examine the nature of individual differences in lapses of attention and their relation to executive and fluid abilities. Participants performed a sustained attention task along with multiple measures of executive control and fluid abilities. Lapses of attention were indexed based on the slowest reaction times in terms of both quintiles and the τ parameter from the ex-Gaussian distribution. It was found that the slowest, but not the fastest, RTs in the sustained attention task were related to a broad based executive control factor and a fluid intelligence factor. The results further suggested that only the working memory capacity and response inhibition sub-executive control factors were related to the slowest RTs, with the fluency measures not being related to any of the RT variables. The results are consistent with the idea that fluctuations or lapses in sustained attention, as indexed by the slowest responses, are related to executive control and fluid abilities.