Working Memory Period: The Endurance of Mental Representations

Charting the trajectory of forgetting: Insights from a working memory period paradigm

Working memory capacity is commonly measured in terms of its item span, and much less often in terms of its time span, or “period.” The former measures how many items can be stored in working memory when carrying out episodes of concurrent processing. The latter complements this by determining the duration of processing episodes that can be tolerated while successfully storing a fixed number of items. We investigated the generality of previous evidence that working memory period varies with the distribution of longer and shorter processing episodes within a trial, and that notwithstanding such differences, a global measure of period is a reliable predictor of children’s educational attainment. We describe data from 184 children, between 7 and 11 years of age, who completed variants of an operation period task with different distributions of processing episodes together with measures of scholastic attainment. Individual differences in period scores were consistent over two test sessions, and were predictive of reading and number skills. We replicated previous effects of the order of longer and shorter processing episodes, but found that they did not generalize fully to other manipulations of order. The results point to the contribution of subtle within-trial sequence configurations for working memory. We make the case for a broader view of what constrains working memory than exists in current models.

Phonological similarity effects in verbal complex span

Phonological similarity effects were used to assess the role of acoustic coding in verbal complex span, a processing-plus-storage measure found to correlate significantly with aspects of complex cognition. Three experiments demonstrated consistent effects of phonological similarity on listening span. These effects appeared relatively insensitive to manipulations of task materials (Experiment 1) and differences in processing task demands (Experiments 2 and 3). The results were interpreted as reflecting a significant role for the phonological loop in supporting verbal complex span and a multicomponent view of working memory, as tapped by these tests. Phonological similarity did not significantly interact with aspects of the tasks varied across Experiments 1 to 3, suggesting a relative robustness of the effect. However, variation in the phonological similarity effect sizes across Experiments 1 to 3 supports the suggestion that task demands and characteristics have the potential to disrupt the phonological similarity effect and, by implication, the reliance on a phonological code.

Working Memory Maturation: Can We Get at the Essence of Cognitive Growth?

The theoretical and practical understanding of cognitive development depends on working memory, the limited information temporarily accessible for such daily activities as language processing and problem solving. In this article, I assess many possible reasons that working memory performance improves with development. A first glance at the literature leads to the weird impression that working memory capacity reaches adult levels during infancy but then regresses during childhood. In place of that unlikely explanation, I consider how infant studies may lead to overestimates of capacity if one neglects supports that the tasks provide, compared with adult-level tasks. Further development of working memory during the school years is also considered. Many investigators have come to suspect that working memory capacity may be constant after infancy because of various factors such as developmental increases in knowledge, filtering out of irrelevant distractions, encoding and rehearsal strategies, and pattern formation. With each of these factors controlled, though, working memory still improves during the school years. Suggestions are made for research to bridge the gap between infant and child developmental research, to understand the focus and control of attention in working memory and how these skills develop, and to pinpoint the nature of capacity and its development from infancy forward.

The Mid-Career Award

Working memory is an extremely influential concept within experimental psychology, with, at the time of writing, over 90 papers with this term in their title published in this journal alone since 2000. One reason for this interest is that measures of working memory tend to be strong correlates of important indices of real-world function. In addition, at first sight working memory appears to be a relatively simple concept to understand. However, despite this apparent simplicity, explaining working memory performance is not straightforward. In this paper I address this challenge, with a particular focus on the development of working memory performance in children; both children developing typically and those experiencing atypical development. I specifically highlight the multiple constraints on working memory performance, and how these constraints inter-relate. I then consider the broader theoretical implications of each of these constraints for current accounts of working memory and its development.

Children's verbal working memory: role of processing complexity in predicting spoken sentence comprehension

PURPOSE

This study investigated the role of processing complexity of verbal working memory tasks in predicting spoken sentence comprehension in typically developing children. Of interest was whether simple and more complex working memory tasks have similar or different power in predicting sentence comprehension.

METHOD

Sixty-five children (6- to 12-year-olds) completed a verbal working memory (listening) span task that varied in syntactic processing difficulty (simple sentences representing a "simple working memory task," complex sentences representing a "complex working memory task") and a standardized sentence comprehension test.

RESULTS

Word recall on the simple and complex working memory tasks correlated with each other. Both memory tasks also correlated with children's sentence comprehension. Regression analyses showed that the simple working memory task remained a significant predictor of comprehension even after accounting for variance associated with age and performance on the complex working memory task.

CONCLUSIONS

Results were interpreted to suggest that relative to more complex verbal working memory tasks, simple tasks are more robust predictors of children's sentence comprehension because they represent a basic yet robust index of working memory that sufficiently captures controlled attentional focus.

Test-retest reliability of an emotion maintenance task

Research on working memory has suggested domain-specific components for visual, verbal, and spatial information, and more recently for emotion. Affective working memory has been proposed as the set of processes involved in the maintenance of emotions to guide behaviour. The current study examined the reliability of an emotion maintenance/affective working memory task over two experimental sessions separated by one week. Subjective accuracy based on individual ratings was found to correlate over time and was highest for negatively valenced pictures. Results suggest that this paradigm is a reliable measure of emotion maintenance, underscoring the utility of this measure as an assessment tool for normative and clinical populations.

Synergies between processing and memory in children's reading span

Previous research has established the relevance of working memory for cognitive development. Yet the factors responsible for shaping performance in the complex span tasks used to assess working memory capacity are not fully understood. We report a study of reading span in 7- to 11-year-old children that addresses several contemporary theoretical issues. We demonstrate that both the timing and the accuracy of recall are affected by the presence or absence of a semantic connection between the processing requirement and the memoranda. Evidence that there can be synergies between processing and memory argues against the view that complex span simply measures the competition between these activities. We also demonstrate a consistent relationship between the rate of completing processing operations (sentence reading) and recall accuracy. At the same time, the shape and strength of this function varies with the task configuration. Taken together, these results demonstrate the potential for reconstructive influences to shape working memory performance among children.

Task experience and children's working memory performance: a perspective from recall timing

Working memory is an important theoretical construct among children, and measures of its capacity predict a range of cognitive skills and abilities. Data from 9- and 11-year-old children illustrate how a chronometric analysis of recall can complement and elaborate recall accuracy in advancing our understanding of working memory. A reading span task was completed by 130 children, 75 of whom were tested on 2 occasions, with sequence length either increasing or decreasing during test administration. Substantial pauses occur during participants' recall sequences, and they represent consistent performance traits over time, while also varying with recall circumstances and task history. Recall pauses help to predict reading and number skills, alongside as well as separate from levels of recall accuracy. The task demands of working memory change as a function of task experience, with a combination of accuracy and response timing in novel task situations being the strongest predictor of cognitive attainment.

Regulation of cognitive resources during sustained attention and working memory in 10-year-olds and adults

We examined differences between 10-year-olds and young adults in resource recruitment and regulation during tasks of sustained attention and spatial working memory. We administered participants spatial 0- and 1-back tasks and used pupillary dilation as a measure of resource recruitment. Repeated administration of 0-back led to smaller pupillary dilations and greater response time (RT) variability, revealing a vigilance decrement. Effects of repeated administration of 0-back and differences between 0- and 1-back in d' and RTs were similar between ages. Results further suggested that the children may not have been as effective as adults in extracting frequency information. Thus, on simple tasks of sustained attention and working memory, children recruit resources in a manner similar to adults. Finally, d' was correlated with RT variability on both tasks at both ages, highlighting the role of attentional fluctuations on both tasks.

Individual differences in working memory

Working memory can be defined as the ability to hold in mind information in the face of potentially interfering distraction in order to guide behavior. The experimental manipulation of working memory tasks has shed considerable light on the probable structure of the human working memory system, and, to a lesser extent, the specific processes captured by working memory paradigms. However, individual differences research has also had a crucial role to play in the development of theories of working memory. In particular, correlational approaches have been particularly informative in three areas of working memory research, each of which is reviewed here. These are, first, the importance of working memory measures as correlates of high-level cognitive skills such as reading, mathematics, reasoning, and fluid intelligence; second, the extent to which human working memory relies on domain-general or domain-specific component subsystems, and third, the precise reasons why working memory measures do relate to other important indices of human cognitive functioning. The findings from each of these areas suggest that working memory depends on a combination of domain-specific representational systems and domain-general processing and control systems, and that working memory measures capture individuals' ability to combine maintenance and processing demands in a manner that limits information loss from forgetting or distraction.