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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory capacity and the top-down control of visual search: Exploring the boundaries of "executive attention".

The executive attention theory of working memory capacity (WMC) proposes that measures of WMC broadly predict higher order cognitive abilities because they tap important and general attention capabilities (R. W. Engle & M. J. Kane, 2004). Previous research demonstrated WMC-related differences in attention tasks that required restraint of habitual responses or constraint of conscious focus. To further specify the executive attention construct, the present experiments sought boundary conditions of the WMC-attention relation. Three experiments correlated individual differences in WMC, as measured by complex span tasks, and executive control of visual search. In feature-absence search, conjunction search, and spatial configuration search, WMC was unrelated to search slopes, although they were large and reliably measured. Even in a search task designed to require the volitional movement of attention (J. M. Wolfe, G. A. Alvarez, & T. S. Horowitz, 2000), WMC was irrelevant to performance. Thus, WMC is not associated with all demanding or controlled attention processes, which poses problems for some general theories of WMC. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binding facilitates attention switching within working memory.

The authors investigated the units of selective attention within working memory. In Experiment 1, a group of participants kept 1 count and 1 location in working memory and updated them repeatedly in random order. Another group of participants were instructed to achieve the same goal by memorizing the verbal and spatial information in an integrative way as a moving digit. The behavioral data showed that switching attention between properties of an integrated working-memory item was faster than switching between respective properties of different items. Experiment 2 demonstrated that this switching facilitation cannot be simply ascribed to the different amount of working-memory items maintained by the two groups of participants. Finally, by adopting a pure verbal task in Experiment 3, the authors observed the same binding facilitation, with the possibility of "location-based selection" excluded. They summarize the observations of all 3 experiments in the study and suggest both a location- and object-based mechanism for attention selection in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in working memory and comprehension: A test of four hypotheses.

A relationship has consistently been found between measures of working memory and reading comprehension. Four hypotheses for this relationship were tested in 3 experiments. In the 1st 2 experiments, a moving window procedure was used to present the operation–word and reading span tasks. High- and low-span Ss did not differentially trade off time on the elements of the tasks and the to-be-remembered word. Furthermore, the correlation between span and comprehension was undiminished when the viewing times were partialed out. Exp 3 compared a traditional experimenter-paced simple word-span and an S-paced span in their relationship with comprehension. The experimenter-paced word-span correlated with comprehension, but the S-paced span did not. The results of all 3 experiments support a general capacity explanation for the relationship between working memory and comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory costs of task switching.

Although many accounts of task switching emphasize the importance of working memory as a substantial source of the switch cost, there is a lack of evidence demonstrating that task switching actually places additional demands on working memory. The present study addressed this issue by implementing task switching in continuous complex span tasks with strictly controlled time parameters. A series of 4 experiments demonstrate that recall performance decreased as a function of the number of task switches and that the concurrent load of item maintenance had no influence on task switching. These results indicate that task switching induces a cost on working memory functioning. Implications for theories of task switching, working memory, and resource sharing are addressed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention control, memory updating, and emotion regulation temporarily reduce the capacity for executive control.

This research tested the hypothesis that initial efforts at executive control temporarily undermine subsequent efforts at executive control. Four experiments revealed that controlling the focus of visual attention (Experiment 1), inhibiting predominant writing tendencies (Experiment 2), taking a working memory test (Experiment 3), or exaggerating emotional expressions (Experiment 4) undermined performance on subsequent tests of working memory span, reverse digit span, and response inhibition, respectively. The results supported a limited resource model of executive control and cast doubt on competing accounts based on mood, motivation, or task difficulty. Prior efforts at executive control are a significant contextual determinant of the operation of executive processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monitoring the information-processing demands of attention switching.

Examined demands on information-processing capacity in 3 experiments with 48 Ss by combining auditory digit-tasks involving attention switching with the secondary task of pursuit tracking. Secondary task scores in 2 experiments were lower for tracking segments involving signalled switches between digit-tasks and between input channels, respectively. These results could not be accounted for by a trade-off between digit-task and tracking performance. When the attended channel was defined by voice quality in a 3rd experiment, tracking performance was not affected by switches between input channels. A comparison of the present results and those of related studies indicates that switching attention per se between input channels does not constitute the primary demand for central processing capacity in dichotic tasks. The increased demand appears to be related instead to the concomitant changes required in the input processing and to the processing of signals to switch the focus of attention. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory, short-term memory, and general fluid intelligence: A latent-variable approach.

A study was conducted in which 133 participants performed 11 memory tasks (some thought to reflect working memory and some thought to reflect short-term memory), 2 tests of general fluid intelligence, and the Verbal and Quantitative Scholastic Aptitude Tests. Structural equation modeling suggested that short-term and working memories reflect separate but highly related constructs and that many of the tasks used in the literature as working memory tasks reflect a common construct. Working memory shows a strong connection to fluid intelligence, but short-term memory does not. A theory of working memory capacity and general fluid intelligence is proposed: The authors argue that working memory capacity and fluid intelligence reflect the ability to keep a representation active, particularly in the face of interference and distraction. The authors also discuss the relationship of this capability to controlled attention, and the functions of the prefrontal cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simple and complex word spans as measures of working memory capacity.

Five experiments investigated the effects of word length in simple word span tasks and complex operation and reading span tasks and the relationship between these tasks and reading comprehension. The 1st 2 experiments showed word length effects using both simple and complex memory span tasks and that both simple and complex span tasks correlated with reading comprehension. In the 3rd experiment, articulatory suppression did not eliminate word length effects. The final experiments showed that articulatory suppression eliminated the effect of word length when words were sampled with replacement from small fixed pools but not when sampled without replacement from a large pool. The word pool effects were not a result of concreteness of the words. It is concluded that the reading span does not measure a working memory specific to reading. Further, in immediate memory experiments, repeating words from trial to trial may lead to a more limited coding than is used with nonrepeated words. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correction to Emery, Hale, and Myerson (2008).

Reports an error in "Age differences in proactive interference, working memory, and abstract reasoning" by Lisa Emery, Sandra Hale and Joel Myerson (Psychology and Aging, 2008[Sep], Vol 23[3], 634-645). The original article contained an incorrect DOI. The correct DOI is as follows: 10.1037/a0012577. (The following abstract of the original article appeared in record 2008-13050-014.) It has been hypothesized that older adults are especially susceptible to proactive interference (PI) and that this may contribute to age differences in working memory performance. In young adults, individual differences in PI affect both working memory and reasoning ability, but the relations between PI, working memory, and reasoning in older adults have not been examined. In the current study, young, old, and very old adults performed a modified operation span task that induced several cycles of PI buildup and release as well as two tests of abstract reasoning ability. Age differences in working memory scores increased as PI built up, consistent with the hypothesis that older adults are more susceptible to PI, but both young and older adults showed complete release from PI. Young adults' reasoning ability was best predicted by working memory performance under high PI conditions, replicating M. Bunting (2006). In contrast, older adults' reasoning ability was best predicted by their working memory performance under low PI conditions, thereby raising questions regarding the general role of susceptibility to PI in differences in higher cognitive function among older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interfering with the central executive by means of a random interval repetition task

Four dual-task experiments are reported in which a short-term memory task is performed concurrently with a random interval repetition task, which was designed to interfere with functions normally attributed to the central executive in the working memory model of Baddeley and Hitch (1974). The task was found to interfere with supra-span serial recall and with backward memory span, but did not disrupt performance on a forward-memory-span task. The effects were observed in dissociation with effects of articulatory suppression and matrix tapping, so that the locus of the effects of the new task is not due to the slave systems. In addition, single-task random-interval repetition performance was sampled and compared to performance in the dual-task conditions of all four experiments. Although quality of tapping performance differed between the single-task and the dual-task conditions, it was not related to recall performance. All the results are discussed with reference to the working memory model.     

Working memory span development: A time-based resource-sharing model account.

The time-based resource-sharing model (P. Barrouillet, S. Bernardin, & V. Camos, 2004) assumes that during complex working memory span tasks, attention is frequently and surreptitiously switched from processing to reactivate decaying memory traces before their complete loss. Three experiments involving children from 5 to 14 years of age investigated the role of this reactivation process in developmental differences in working memory spans. Though preschoolers seem to adopt a serial control without any attempt to refresh stored items when engaged in processing, the reactivation process is efficient from age 7 onward and increases in efficiency until late adolescence, underpinning a sizable part of developmental differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is the focus of attention in working memory expanded through practice?

This article reinvestigates the claim by P. Verhaeghen, J. Cerella, and C. Basak (2004) that the focus of attention in working memory can be expanded from 1 to 4 items through practice. Using a modified version of Verhaeghen et al.'s n-back paradigm, Experiments 1 and 3 show that a signature of a one-item focus, the time cost for switching between items in working memory, persists over practice. Verhaeghen et al. reported a shift over practice from a step function to a linear slope of reaction times over set size and argued that it reflects the expansion of the focus. With an improved counterbalancing scheme, a continuously increasing slope was found even without practice in Experiment 2. The results question the hypothesis that the focus is expanded through practice. They are in line with predictions from a model that distinguishes a one-item focus from a direct-access region holding about 4 items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial and parallel processes in working memory after practice.

Six young adults practiced for 36 sessions on a working-memory updating task in which 2 digits and 2 spatial positions were continuously updated. Participants either did 1 updating operation at a time, or attempted 1 numerical and 1 spatial operation at the same time. In contrast to previous research using the same paradigm with a single digit and a single dot, dual-task costs were not eliminated with practice. Costs of switching between digits and between spatial positions were found throughout practice, supporting the existence of a focus of attention in working memory that can hold 1 digit and 1 spatial position simultaneously, but is not expanded to hold 2 elements of the same kind. The results can be understood by assuming that observed limits on parallel processing, as well as on the capacity of the focus of attention, arise not from structural constraints but rather reflect the optimal configuration of the cognitive system for avoiding information cross-talk in a given task. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Attention and intelligence.

Reviews empirical evidence to show that 2 concepts—attention and intelligence—are related at the empirical level. Data are presented to demonstrate that intelligence correlates with different types of attention, including sustained attention, search, attention switching, and vigilance. The most significant findings are derived from work on divided attention (dual or competing tasks) in which 2 markers for primary factors were given simultaneously on different channels. Under these conditions, the correlation between the components increases, relative to the single-task condition, implying an increase in the general factor loading. The theoretical implications of this finding are discussed in terms of attentional resources and working memory. These results are considered in relation to theories of the structure of abilities and particularly in relation to the theory of fluid and crystallized intelligence. (67 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory and retrieval: A resource-dependent inhibition model.

Four experiments examined individual differences in working memory (WM) capacity and how those differences affect performance on retrieval from both primary and secondary memory. The results showed that WM differences appear only in retrieval from primary memory and then only under conditions that lead to interference or response competition within the task. This suggests that WM capacity is important to retrieval that is based on controlled effortful search but not search that is based on automatic activation. A view is presented suggesting that individual differences in attentional resources lead to differences in the ability to inhibit or suppress irrelevant information. The paradigm also allowed more general comparisons between the processes involved in retrieval from primary and secondary memory. As expected, it was found that retrieval from primary memory was a function of set size. However, for sets larger than 2 items, retrieval from secondary memory was independent of set size. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examining the locus of age effects on complex span tasks.

To investigate the locus of age effects on complex span tasks, the authors evaluated the contributions of working memory functions and processing speed. Age differences were found in measures of storage capacity, language processing speed, and lower level speed. Statistically controlling for each of these in hierarchical regressions substantially reduced, but did not eliminate, the complex span age effect. Accounting for lower level speed and storage, however, removed essentially the entire age effect, suggesting that both functions play important and independent roles. Additional evidence for the role of storage capacity was the absence of complex span age differences with span size calibrated to individual word span performance. Explanations for age differences based on inhibition and concurrent task performance were not supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The complexities of complex span: Explaining individual differences in working memory in children and adults.

Two studies are presented that investigated the constraints underlying working memory performance in children and adults. In each case, independent measures of processing efficiency and storage capacity are assessed to determine their relative importance in predicting performance on complex span tasks, which measure working memory capacity. Results show that complex span performance was independently constrained by individual differences in dornain-general processing efficiency and domain-specific storage capacity. Residual variance, which may reflect the ability to coordinate storage and processing, also predicted academic achievement. These results challenge the view that complex span taps, a limited-capacity resource pool shared between processing and storage operations. Rather, they are consistent with a multiple-component model in which separate resource pools support the processing and storage functions of working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Further evidence for a deficit in switching attention in schizophrenia.

In this study, sustained, selective, divided, and switching attention, and reloading of working memory were investigated in schizophrenia by using a newly developed Visual Attention Battery (VAB). Twenty-four outpatients with schizophrenia and 24 control participants were studied using the VAB. Performance on VAB components was correlated with performance of standard tests. Patients with schizophrenia were significantly impaired on VAB tasks that required switching of attention and reloading of working memory but had normal performance on tasks involving sustained attention or attention to multiple stimulus features. Switching attention and reloading of working memory were highly correlated with Trails (B–A) score for patients. The decline in performance on the switching-attention task in patients with schizophrenia met criteria for a differential deficit in switching attention. Future research should examine the neurophysiological basis of the switching deficit and its sensitivity and specificity to schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in proactive interference, working memory, and abstract reasoning.

[Correction Notice: An erratum for this article was reported in Vol 23(4) of Psychology and Aging (see record 2008-19072-007). The original article contained an incorrect DOI. The correct DOI is as follows: 10.1037/a0012577.] It has been hypothesized that older adults are especially susceptible to proactive interference (PI) and that this may contribute to age differences in working memory performance. In young adults, individual differences in PI affect both working memory and reasoning ability, but the relations between PI, working memory, and reasoning in older adults have not been examined. In the current study, young, old, and very old adults performed a modified operation span task that induced several cycles of PI buildup and release as well as two tests of abstract reasoning ability. Age differences in working memory scores increased as PI built up, consistent with the hypothesis that older adults are more susceptible to PI, but both young and older adults showed complete release from PI. Young adults' reasoning ability was best predicted by working memory performance under high PI conditions, replicating M. Bunting (2006). In contrast, older adults' reasoning ability was best predicted by their working memory performance under low PI conditions, thereby raising questions regarding the general role of susceptibility to PI in differences in higher cognitive function among older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)