Complex Span Research Articles

Comparison of the Working Memory Load in N-Back and Working Memory Span Tasks by Means of EEG Frequency Band Power and P300 Amplitude.

According to theoretical accounts, both, N-back and complex span tasks mainly require working memory (WM) processing. In contrast, simple span tasks conceptually mainly require WM storage. Thus, conceptually, an N-back task and a complex span task share more commonalities as compared to a simple span task. In the current study, we compared an N-back task, a complex operation span task (Ospan), and a simple digit span task (Dspan) by means of typical WM load-related measures of the Electroencephalogram (EEG) like the parietal alpha and beta frequency band power, the frontal theta frequency band power, and the P300 amplitude, to examine whether these tasks would show commonalities or differences in WM processing-load. We expected that increasing WM-load would generally lead to a decreased alpha and beta frequency band power, an increased theta frequency band power, and a decreased P300 amplitude. Yet, based on the conceptual considerations, we hypothesized that the outcomes of these measures would be more comparable between the N-back and the Ospan as compared to the Dspan. Our hypotheses were partly confirmed. The N-back and the Ospan showed timely more prolonged alpha frequency band power effects as compared to the Dspan. This might indicate higher demands on WM processing in the former two tasks. The theta frequency band power and the P300 amplitude were most pronounced in the N-back task as compared to both span tasks. This might indicate specific demands on cognitive control in the N-back task. Additionally, we observed that behavioral performance measures correlated with changes in EEG alpha power of the N-back and the Ospan, yet not of the Dspan. Taken together, the hypothesized conceptual commonalities between the N-back task and the Ospan (and, for the Dspan, differences) were only partly confirmed by the electrophysiological WM load-related measures, indicating a potential need for reconsidering the theoretical accounts on WM tasks and the value of a closer link to electrophysiological research herein.

Syntactic Recursion Facilitates and Working Memory Predicts Recursive Theory of Mind.

In this study, we focus on the possible roles of second-order syntactic recursion and working memory in terms of simple and complex span tasks in the development of second-order false belief reasoning. We tested 89 Turkish children in two age groups, one younger (4;6–6;5 years) and one older (6;7–8;10 years). Although second-order syntactic recursion is significantly correlated with the second-order false belief task, results of ordinal logistic regressions revealed that the main predictor of second-order false belief reasoning is complex working memory span. Unlike simple working memory and second-order syntactic recursion tasks, the complex working memory task required processing information serially with additional reasoning demands that require complex working memory strategies. Based on our results, we propose that children’s second-order theory of mind develops when they have efficient reasoning rules to process embedded beliefs serially, thus overcoming a possible serial processing bottleneck.

Domain-specific interference between storage and processing in complex span is driven by cognitive and motor operations.

The role of domain-specific interference in the complex-span paradigm is still controversial. Here we distinguish two operations within the processing task of this paradigm-a cognitive operation to solve the task and a motor operation to give the answer. Their domain-specific interference with maintenance was investigated within the complex-span paradigm. Presentation of the memoranda-six words or four spatially distributed dots-was interleaved with the presentation of letter pairs to be processed. Cognitive operation domain was manipulated by asking participants to make either a rhyme judgment or a symmetry judgment for each letter pair. Motor operation domain was varied by requiring a response by either speaking or pointing. Cognitive load was held constant. Cognitive and motor operation showed separate domain-specific effects on memory: Visuospatial memory was impaired more by visuospatial than verbal cognitive operations and more by manual-spatial than oral motor operations. In contrast, verbal memory performance was worse when verbal cognitive operations and oral motor operations were executed. The results are discussed in relation to the multicomponent model, the time-based resource-sharing (TBRS) model, and the Serial Order in a Box-Complex-Span (SOB-CS) model. They imply that models of working memory must incorporate mechanisms that allow for domain-specific interference in the verbal and the visuospatial domain.

The concentric model of human working memory: A validation study using complex span and updating tasks

The concentric model of human working memory: A validation study using complex span and updating tasks

Modulatory Effect of Motivation on the Association of Trait Anxiety and Cognitive Performance: A Pupillometric Study

The attentional control theory (ACT) proposes that trait anxiety disrupts functional efficiency of executive control of attention relating to working memory system such as shifting. ACT also emphasizes the modulatory role of motivation in anxiety on cognitive task performance. The present study investigated the association of trait anxiety-related inefficiencies in attentional shift and working memory performance in conjunction with the level of motivation. A variation of complex span paradigm is designed to systematically manipulate the time constraint on shifting attentional focus back and forth between working memory contents and processing task was used in this study. In the experiment, participants high and low in trait anxiety were allocated either high or low motivation induction conditions, and performed a series of complex span tasks. They also completed a state anxiety measure before and after the experimental task. Motivational states were assessed by the pupil dilation, which is known to reflect the amount of cognitive effort invested on the task at hand. Results showed that, only in low motivation condition, high trait-anxious individuals exhibited greater difficulty, relative to those low in trait anxiety, in maintaining working memory contents as the task demand increased. State anxiety showed no relation to working memory performance regardless of the level of motivation and task demands. Pupillary responses revealed that, in high motivational state, high trait-anxious individuals invested more effort than those low in trait anxiety when the task demand was low, F(1, 132) = 6.65, p = 0.0110, to moderate, F(1, 132) = 8.441, p = 0.00043. In accordance with ACT, these findings suggest that motivation can modulate the association between trait anxiety and cognitive performance along with the levels of task demand. Clinical implication is briefly discussed.

Computational and behavioral investigations of the SOB-CS removal mechanism in working memory

The SOB-CS computational model of working memory explains findings from simple and complex span experiments. According to the model’s mechanism of interference by superposition, high similarity between memory items and subsequently processed distractors is beneficial because the more a distractor is similar to an item, the more they share similar units, leading to less distortion of the memory item. When time allows, SOB-CS removes interfering distractors from memory by unbinding them from their context. The combination of these two mechanisms leads to the prediction that when free time is long enough to remove the distractors entirely, similarity between items and distractors should no longer be beneficial to memory performance. The aim of our study was to test this prediction with humans and simulations. Experimental data disconfirmed the prediction. Simulations showed that SOB-CS overestimated the strength of removal which has to be much lower than expected to account for experimental data.

A Closer Look at Who “Chokes Under Pressure”

Previous research has shown that the higher one's working memory capacity, the more likely his/her performance is to be negatively impacted by performance pressure. In the current research we examined potential explanations for this finding by assessing the relation between pressure-induced performance deficits (i.e. “choking under pressure”) in math-based problem solving and individual differences in both working memory (as assessed via complex span tasks) and attentional control (as assessed via two measures from an Eriksen Flanker task). We find higher working memory only relates to “choking under pressure” when individuals were low in attentional control. These results further elucidate the mechanism by which high-pressure scenarios can lead to errors in performance and carry implications for developing effective intervention strategies to prevent poor performance in high-stakes situations.

Working Memory Capacity, Mind Wandering, and Creative Cognition: An Individual-Differences Investigation into the Benefits of Controlled Versus Spontaneous Thought.

Should executive control, as indicated by working memory capacity (WMC) and mind-wandering propensity, help or hinder creativity? Sustained and focused attention should help guide a selective search of solution-relevant information in memory and help inhibit uncreative, yet accessible, ideas. However, unfocused attention and daydreaming should allow mental access to more loosely relevant concepts, remotely linked to commonplace solutions. Three individual-differences studies inserted incubation periods into one or two divergent thinking tasks and tested whether WMC (assessed by complex span tasks) and incubation-period mind wandering (assessed as probed reports of task-unrelated thought [TUT]) predicted post-incubation performance. Retrospective self-reports of Openness (Experiment 2) and mind-wandering and daydreaming propensity (Experiment 3) complemented our thought-probe assessments of TUT. WMC did not correlate with creativity in divergent thinking, whereas only the questionnaire measure of daydreaming, but not probed thought reports, weakly predicted creativity; the fact that in-the-moment TUTs did not correlate divergent creativity is especially problematic for claims that mind-wandering processes contribute to creative cognition. Moreover, the fact that WMC tends to strongly predict analytical problem solving and reasoning, but may not correlate with divergent thinking, provides a useful boundary condition for defining WMC's nomological net. On balance, our data provide no support for either benefits or costs of executive control for at least one component of creativity.

Maintenance of item and order information in verbal working memory

ABSTRACTAlthough verbal recall of item and order information is well-researched in short-term memory paradigms, there is relatively little research concerning item and order recall from working memory. The following study examined whether manipulating the opportunity for attentional refreshing and articulatory rehearsal in a complex span task differently affected the recall of item- and order-specific information of the memoranda. Five experiments varied the opportunity for articulatory rehearsal and attentional refreshing in a complex span task, but the type of recall was manipulated between experiments (item and order, order only, and item only recall). The results showed that impairing attentional refreshing and articulatory rehearsal similarly affected recall regardless of whether the scoring procedure (Experiments 1 and 4) or recall requirements (Experiments 2, 3, and 5) reflected item- or order-specific recall. This implies that both mechanisms sustain the maintenance of item and order information, and suggests that the common cumulative functioning of these two mechanisms to maintain items could be at the root of order maintenance.

Impact of early second-language acquisition on the development of first language and verbal short-term and working memory

ABSTRACTThe present study aimed at investigating whether L2 learning affects phonological short-term and working memory and first language (L1) development. The performance of a group of 31 4- to-5-year-old sequential bilinguals attending an International School on tasks assessing phonological short-term and working memory and linguistic performance in L1 was compared to that of a group of 31 age-matched monolinguals. The bilingual group outperformed monolinguals on two simple and one complex span task assessing phonological short-term and working memory, respectively. They performed as monolinguals on measures assessing articulatory skills, phonological abilities, naming and grammatical processing in L1. However, bilingual participants performed worse than monolinguals on a test of lexical comprehension. These results are discussed in light of current models of cognitive development.

Measuring Working Memory Capacity on the Web with the Online Working Memory Lab (the OWL)

The Complex Span paradigm is one of the most influential and widely used instruments for measuring working memory capacity (WMC). We report the results of four experiments designed to explore the feasibility of obtaining valid estimates of WMC online. We explored the relationships between the Complex Span tasks and fluid intelligence (gF) in the lab and on the web using a new platform called the Online Working Memory Lab (the OWL). The OWL is universally accessible across all computer operating systems and functions in both local and remote contexts, allowing researchers to sample more diverse subjects from practically anywhere. Experiments 1 and 2 showed that the Complex Span failed to predict gF when the to-be-remembered stimuli were letters and the tests were taken online. We increased the predictive validity of the test battery in Experiments 3 and 4 by replacing the letters with memory stimuli that were more difficult to write down in an unproctored setting. This work describes our most recent attempts to measure working memory capacity in the wild.

Effects of Auditory Working Memory Tasks while Switching between Autonomous and Manual Driving

As the prevalence of autonomous vehicles onto the road increases, understanding the cognitive processes of the inevitably distracted driver is important. When engaged in a secondary task while driving, the driver’s limited supply of attentional resources is diminished, resulting in less attention available to process the unpredictable road ahead. While driving distracted causes performance to suffer across the board (Fitousi & Wenger, 2011), some individuals are more apt at multitasking than others due to a high working memory capacity (WMC). We evaluated the differences in braking reaction times (RT) according to individual difference in WMC, specifically while driving in an autonomous car simulation and engaged in a cognitively demanding task. Results showed an interaction between current level of cognitive load and an individual’s WMC where individuals who scored lower on a complex operation span task (OSPAN) experienced greater RTs compared to individuals who scored higher. Average RT during the autonomous scenario, in which OSPAN was concurrently performed, yielded a 33% increase in RT compared to baseline RT with the same OSPAN task. Additionally, sleep and length of time spent in autonomous mode influenced RT.

Individual Differences in Working Memory Capacity Modulates Semantic Negative Priming from Single Prime Words.

The present study investigated whether semantic negative priming from single prime words depends on the availability of cognitive control resources. Participants with high vs. low working memory capacity (as assessed by their performance in complex span and attentional control tasks) were instructed to either attend to or ignore a briefly presented single prime word that was followed by either a semantically related or unrelated target word on which participants made a lexical decision. Individual differences in working memory capacity (WMC) mainly affected the processing of the ignored primes, but not the processing of the attended primes: While the latter produced reliable positive semantic priming for both high- and low-WMC participants, the former gave rise to reliable semantic negative priming only for high WMC participants, with low WMC participants showing the opposite positive priming effect. The present results extend previous findings in demonstrating that (a) single negative priming can reliably generalize to semantic associates of the prime words, and (b) a differential availability of cognitive control resources can reliably modulate the negative priming effect at a semantic level of representation.

Control of information in working memory: Encoding and removal of distractors in the complex-span paradigm

The article reports four experiments with complex-span tasks in which encoding of memory items alternates with processing of distractors. The experiments test two assumptions of a computational model of complex span, SOB-CS: (1) distractor processing impairs memory because distractors are encoded into working memory, thereby interfering with memoranda; and (2) free time following distractors is used to remove them from working memory by unbinding their representations from list context. Experiment 1 shows that distractors are erroneously chosen for recall more often than not-presented stimuli, demonstrating that distractors are encoded into memory. Distractor intrusions declined with longer free time, as predicted by distractor removal. Experiment 2 shows these effects even when distractors precede the memory list, ruling out an account based on selective rehearsal of memoranda during free time. Experiments 3 and 4 test the notion that distractors decay over time. Both experiments show that, contrary to the notion of distractor decay, the chance of a distractor intruding at test does not decline with increasing time since encoding of that distractor. Experiment 4 provides additional evidence against the prediction from distractor decay that distractor intrusions decline over an unfilled retention interval. Taken together, the results support SOB-CS and rule out alternative explanations. Data and simulation code are available on Open Science Framework: osf.io/3ewh7.

I. WORKING MEMORY CAPACITY IN CONTEXT: MODELING DYNAMIC PROCESSES OF BEHAVIOR, MEMORY, AND DEVELOPMENT.

Working memory is a vital cognitive skill that underlies a broad range of behaviors. Higher cognitive functions are reliably predicted by working memory measures from two domains: children's performance on complex span tasks, and infants' performance in looking paradigms. Despite the similar predictive power across these research areas, theories of working memory development have not connected these different task types and developmental periods. The current project takes a first step toward bridging this gap by presenting a process-oriented theory, focusing on two tasks designed to assess visual working memory capacity in infants (the change-preference task) versus children and adults (the change detection task). Previous studies have shown inconsistent results, with capacity estimates increasing from one to four items during infancy, but only two to three items during early childhood. A probable source of this discrepancy is the different task structures used with each age group, but prior theories were not sufficiently specific to explain how performance relates across tasks. The current theory focuses on cognitive dynamics, that is, how memory representations are formed, maintained, and used within specific task contexts over development. This theory was formalized in a computational model to generate three predictions: 1) capacity estimates in the change-preference task should continue to increase beyond infancy; 2) capacity estimates should be higher in the change-preference versus change detection task when tested within individuals; and 3) performance should correlate across tasks because both rely on the same underlying memory system. I also tested a fourth prediction, that development across tasks could be explained through increasing real-time stability, realized computationally as strengthening connectivity within the model. Results confirmed these predictions, supporting the cognitive dynamics account of performance and developmental changes in real-time stability. The monograph concludes with implications for understanding memory, behavior, and development in a broader range of cognitive development.

Anxiety and working memory capacity: A meta-analysis and narrative review.

Cognitive deficits are now widely recognized to be an important component of anxiety. In particular, anxiety is thought to restrict the capacity of working memory by competing with task-relevant processes. The evidence for this claim, however, has been mixed. Although some studies have found restricted working memory in anxiety, others have not. Within studies that have found impairments, there is little agreement regarding the boundary conditions of the anxiety/WMC association. The aim of this review is to critically evaluate the evidence for anxiety-related deficits in working memory capacity. First, a meta-analysis of 177 samples (N = 22,061 individuals) demonstrated that self-reported measures of anxiety are reliably related to poorer performance on measures of working memory capacity (g = -.334, p < 10-29). This finding was consistent across complex span (e.g., OSPAN; g = -.342, k = 30, N = 3,196, p = .000001), simple span (e.g., digit span; g = -.318, k = 127, N = 17,547, p < 10-17), and dynamic span tasks (e.g., N-Back; g = -.437, k = 20, N = 1,318, p = .000003). Second, a narrative review of the literature revealed that anxiety, whether self-reported or experimentally induced, is related to poorer performance across a wide variety of tasks. Finally, the review identified a number of methodological limitations common in the literature as well as avenues for future research. (PsycINFO Database Record

How a high working memory capacity can increase proactive interference.

Previous findings suggested that a high working memory capacity (WMC) is potentially associated with a higher susceptibility to proactive interference (PI) if the latter is measured under high cognitive load. To explain such a finding, we propose to consider susceptibility to PI as a net effect of individual executive processes and the intrinsic potential for PI. With the latter, we refer to the amount of information that is activated at a given time and that has the potential to exert PI subsequently. In two studies deploying generalized linear mixed models, susceptibility to PI was modeled as the decline of performance over trials of a complex span task. The results revealed that a higher WMC was associated with a higher susceptibility to PI. Moreover, the number of stimuli recalled in one trial as a proxy variable for the intrinsic potential for PI negatively affected memory performance in the subsequent trial.

Asymmetric interference between domains: evidence from the stimulus order effect in complex span tasks

ABSTRACTThe stimulus order effect refers to the finding that recall in complex span tasks is better when span lists begin with a longer processing task and end with a shorter task than when these processing tasks are presented in the reverse order. This study independently manipulated processing time and processing difficulty between Long-final and Short-final lists. The processing task required participants to solve arithmetic problems with either verbal (Experiment 1) or visuospatial (Experiment 2) materials. The memory items used in the storage task were either digits (verbal material) or dots-in-matrices (visuospatial materials). Storage of both verbal and visuospatial materials was sensitive to the change in processing difficulty, but not processing time. Furthermore, this study provides further evidence for the asymmetry of domain interference in working memory. The similarities and differences between verbal and visuospatial storage in working memory are discussed.

Individual Differences in Working Memory Capacity and Shooting Behavior

Previous research on the relation between working memory capacity (WMC) and shooting behavior suggests that individuals with low working memory spans are more prone to shooting errors than are individuals with high working memory spans. The present study investigated how WMC interacts with the proportion of “shoot” to “don’t shoot” decisions to affect overall shooting performance. Participants were 186 undergraduate students who completed a series of complex span tasks, rated a series of negative photographs for valence and arousal, and then completed a computerized shooting task in which participants were shooting on 20%, 50%, or 80% of the trials. Results indicated that participants with high working memory spans outperformed participants with low working memory spans in all conditions. Participants also exhibited a greater tendency to inappropriately shoot as the proportion of shoot decisions increased. These results suggest that WMC and the proportion of shoot trials interact to affect shooting behavior.

A simultaneous examination of two forms of working memory training: Evidence for near transfer only.

The efficacy of working-memory training is a topic of considerable debate, with some studies showing transfer to measures such as fluid intelligence while others have not. We report the results of a study designed to examine two forms of working-memory training, one using a spatial n-back and the other a verbal complex span. Thirty-one undergraduates completed 4weeks of n-back training and 32 completed 4weeks of verbal complex span training. We also included two active control groups. One group trained on a non-adaptive version of n-back and the other trained on a real-time strategy video game. All participants completed pre- and post-training measures of a large battery of transfer tasks used to create composite measures of short-term and working memory in both verbal and visuo-spatial domains as well as verbal reasoning and fluid intelligence. We only found clear evidence for near transfer from the spatial n-back training to new forms of n-back, and this was the case for both adaptive and non-adaptive n-back.