Low Working Memory Research Articles

Individual differences in working memory capacity predict benefits to memory from intention offloading

ABSTRACT Research suggests that individuals with lower working memory have difficulty remembering to fulfil delayed intentions. The current study examined whether the ability to offload intentions onto the environment mitigated these deficits. Participants (N = 268) completed three versions of a delayed intention task with and without the use of reminders, along with three measures of working memory capacity. Results showed that individuals with higher working memory fulfilled more intentions when having to rely on their own memory, but this difference was eliminated when offloading was permitted. Individuals with lower working memory chose to offload more often, suggesting that they were less willing to engage in effortful maintenance of internal representations when given the option. Working memory was not associated with metacognitive confidence or optimal offloading choices based on point value. These findings suggest offloading may help circumvent capacity limitations associated with maintaining and remembering delayed intentions.

Modulation of Visual Working Memory Performance via Different Theta Frequency Stimulations.

Previous studies have found that transcranial alternating current stimulation (tACS) can significantly enhance individuals’ working memory performance. However, it is still unclear whether the memory performance enhancement was attributed to the quantity or the quality of working memory. The current study applies tACS over the right parietal cortex at slower (4 Hz) and faster (7 Hz) frequencies to participants with high and low working memory capacities in a color recall memory task. This enabled us to explore the tACS effects on the quantity and quality of the working memory for individuals with different memory capacities. The results revealed that slower frequency (4 Hz) tACS enhanced the quality of memory representations, and faster frequency (7 Hz) tACS principally impaired the quantity of working memory. The underlying mechanism of this effect might be that tACS at different frequencies modulate the memory resources, which then selectively affect the quantity and quality of memory representations. Importantly, individual traits, as well as memory strategies, may be crucial factors to consider when testing the effect of tACS on working memory performance.

Child neurocognitive functioning influences the effectiveness of specific techniques in behavioral teacher training for ADHD: Moderator analyses from a randomized controlled microtrial.

Childhood attention-deficit/hyperactivity disorder (ADHD) is associated with several neurocognitive impairments. Whether these impairments influence the effectiveness of techniques that are commonly used in behavioral teacher training for ADHD has not been investigated so far. In this microtrial, teachers of 90 children with ADHD symptoms (6-12years) were randomly assigned to a short intervention consisting of either antecedent-based (stimulus-control) techniques or consequent-based (contingency management) techniques, or to a waitlist control condition. Primary outcome was the daily assessment of individually selected problem behavior, assessed pre- and post-intervention. Potential neurocognitive moderators of treatment effect included teacher ratings of cognitive control, reward, and punishment sensitivity, and measures derived from computerized neurocognitive tasks, including attentional lapses, interference control, visuospatial working memory, and emotional functioning. Intervention condition by moderator interactions were assessed in separate multilevel mixed models. Lapses of attention, working memory, and emotional functioning interacted with intervention effectiveness. Antecedent-based techniques were effective independent of these neurocognitive functions; consequent-based techniques were (more) effective when these functions were more impaired. The effectiveness of techniques was neither related to interference control nor to teacher-rated neurocognitive functioning. This study showed that child neurocognitive functioning influences the effectiveness of behavioral teacher techniques for children with ADHD symptoms. Findings suggest that antecedent-based techniques may be effective for all children, while consequent-based techniques have added value particularly for children who suffer from low visuospatial working memory, low emotional functioning, and/or large numbers of attentional lapses.

Capacity differences in working memory based on resting state brain networks

Herein, we compared the connectivity of resting-state networks between participants with high and low working memory capacity groups. Brain network connectivity was assessed under both resting and working memory task conditions. Task scans comprised dual-task (reading sentences while memorizing target words) and single-task (reading sentences) conditions. The low capacity group showed relatively stronger connectivity during resting-state in most brain regions, and the high capacity group showed a stronger connectivity between the medial prefrontal and posterior parietal cortices. During task performance, the dorsal attention and salience networks were relatively strongly connected in the high capacity group. In the comparison between dual- and single-task conditions, increased coupling between the anterior cingulate cortex and other attentional control-related areas were noted in the high capacity group. These findings suggest that working memory differences are related with network connectivity variations in attentional control-associated regions during both resting and task performance conditions.

Cerebral blood flow and cognitive outcome after pediatric stroke in the middle cerebral artery

Adaptive recovery of cerebral perfusion after pediatric arterial ischemic stroke (AIS) is sought to be crucial for sustainable rehabilitation of cognitive functions. We therefore examined cerebral blood flow (CBF) in the chronic stage after stroke and its association with cognitive outcome in patients after pediatric AIS. This cross-sectional study investigated CBF and cognitive functions in 14 patients (age 13.5 ± 4.4 years) after pediatric AIS in the middle cerebral artery (time since AIS was at least 2 years prior to assessment) when compared with 36 healthy controls (aged 13.8 ± 4.3 years). Cognitive functions were assessed with neuropsychological tests, CBF was measured with arterial spin labeled imaging in the anterior, middle, and posterior cerebral artery (ACA, MCA, PCA). Patients had significantly lower IQ scores and poorer cognitive functions compared to healthy controls (p < 0.026) but mean performance was within the normal range in all cognitive domains. Arterial spin labeled imaging revealed significantly lower CBF in the ipsilesional MCA and PCA in patients compared to healthy controls. Further, we found significantly higher interhemispheric perfusion imbalance in the MCA in patients compared to controls. Higher interhemispheric perfusion imbalance in the MCA was significantly associated with lower working memory performance. Our findings revealed that even years after a pediatric stroke in the MCA, reduced ipsilesional cerebral blood flow occurs in the MCA and PCA and that interhemispheric imbalance is associated with cognitive performance. Thus, our data suggest that cerebral hypoperfusion might underlie some of the variability observed in long-term outcome after pediatric stroke.

Effects of Depressed Mood on Syllogistic Reasoning: The Buffering Role of High Working Memory Span.

Previous research provided consistent evidence for the existence of the unique cognitive limitation in depressed mood: the impairment of the construction of mental models. In the current research, we applied the classical paradigm using categorical syllogisms to examine the relationship between depressed mood and integrative reasoning, aiming at gathering research evidence on the moderating role of the operation span of working memory. Specifically, we examine the hypothesis that high working memory capacity is a buffering variable and acts as a protective factor preventing the negative impact of depressed mood on syllogistic reasoning. A categorical syllogism, in the simpler evaluative form, consists of two premises (that are assumed to be true) and a conclusion that is to be evaluated as valid (when it follows logically from the premises) or invalid (when it does not follow from the premises). In the cover story, we informed participants that they would read about some observations carried out in a normal garden (believable conclusions) versus in a garden with radical genetic transformations (unbelievable conclusions) in order to stimulate the emergence of belief bias. The participants were 115 high school students who filled out the BDI scale and completed the OSPAN task. In line with predictions, there were main effects of depressed mood and operation span on the accuracy of performance (worse performance in the group with a high in comparison to a low level of depressed mood and much worse performance in low compared to high OSPAN participants). The analyses yielded a strong interaction effect of Depressed mood × OSPAN × Conflict. For participants with high levels of working memory capacity, there were no limitations related to a high level of depressed mood in syllogistic reasoning. On the other hand, a different pattern emerged for participants with low working memory span. In this group, participants with a high level of depressed mood in comparison to those with a low level of depressed mood showed much higher limitations in syllogistic reasoning, especially in reasoning concerning conflict syllogisms. We discuss the implications of this research for recent therapeutic programs using computerized cognitive tasks aimed at individuals with a high level of depressed mood.

Children and adolescents with neurodevelopmental disorders show cognitive heterogeneity and require a person-centered approach

We aimed to identify patterns of cognitive differences and characterize subgroups of Mexican children and adolescents with three neurodevelopmental disorders (NDD): intellectual disability (ID), autism spectrum disorders (ASD) and attention deficit/hyperactivity disorder (ADHD). The sample included 74 children and adolescents 6–15 years; 34% had ID, ASD or ADHD, 47% had ID in comorbidity with ASD, ADHD or both, 11% had ASD + ADHD, 8% were children without NDD. We applied WISC-IV, Autism Diagnostic Interview-Revised, Mini-International Neuropsychiatric Structured Interview, Child Behavior Checklist, and UNICEF Child Functioning Module. We evaluated the normality of the WISC-IV sub-scales using the Shapiro-Francia test, then conducted a latent class analysis and assessed inter-class differences in terms of household, parent and child characteristics. The following four-class solution best fit the data: “Lower Cognitive Profile” (LCP), “Lower Working Memory” (LWM), “Higher Working Memory” (HWM), “Higher Cognitive Profile” (HCP). LCP included most of the children with ID, who had a low Working Memory (WM) index score. LWM included mainly children with ASD or ID + ADHD; their Perceptual Reasoning (PR) and Processing Speed (PS) index scores were much higher than those for Verbal Comprehension (VC) and WM. HWM included children with ASD or ADHD; their scores for PR, PS and VC were high with lower WM (although higher than for LWM). HCP included children without NDD and with ASD or ADHD or both and had the highest scores on all indices. Children with NDD show cognitive heterogeneity and thus require individualized treatment plans.

Spatial Separation and Working Memory Capacity Affect Selective Visual Attention in the Periphery.

The current study aimed to examine the effects of spatial separation and working memory capacity on selective visual attention. We investigated differences in the ability to identify the two covertly attended stimuli that appeared either along one of the meridians (e.g., both along the horizontal) or along two of the meridians (e.g., one along the horizontal and one along the vertical) in the attention-window task. Two visual stimuli in the periphery could be perceived along wider extents of the attentional focus’ meridians (horizontal, vertical, and diagonal) when they were located along the same meridian (e.g., horizontal) compared to two different ones (e.g., horizontal and vertical). Subjects with high working memory capacity outperformed subjects with lower working memory capacity in both conditions and stimuli presented on two meridians were less accurately perceived. The findings support the proposal that individual differences in working memory capacity are important for selective spatial visual attention.

Working memory load reduces the processing of outcome evaluation involving others but not oneself: Event-related potential evidence.

Previous event-related potential (ERP) studies have suggested that self-related and non-self-related outcomes are processed simultaneously. However, the studies investigated situations in which individuals had sufficient attentional/cognitive resources to process both of the outcomes. It is unknown whether self-related and non-self-unrelated outcomes could still be processed simultaneously when resources are limited. To address this issue, 32 female participants in the present study were asked to perform a working memory task. To manipulate the amount of available attentional/cognitive resources, participants were asked to memorize a letter in the low load condition and five letters in the high load condition. During letter consolidation, participants were informed that they and another player each performed a gambling task and were subsequently presented with both of the outcomes. ERP results showed that others' monetary loss elicited larger P200 and late positive potential amplitudes than others' monetary gain under a low working memory load, whereas a high load reduced these effects. However, working memory load did not influence the effect of self-outcome on ERP responses. Therefore, the findings suggest that the amount of available attentional/cognitive resources alters the evaluation of non-self-related but not self-related outcomes.

Cerebrovascular Contributions to Neurocognitive Disorders in People Living With HIV.

To investigate a comprehensive array of magnetic resonance imaging (MRI)-based biomarkers of cerebrovascular disease (CVD) in a cohort of people living with HIV (PLWH) and relate these imaging biomarkers to cognition. Cross-sectional, community-based study. Participants were PLWH in New York City, aged 50 years or older. They underwent a brain magnetic resonance angiography or MRI to ascertain 7 MRI markers of CVD: silent brain infarcts, dilated perivascular spaces, microhemorrhages, white matter hyperintensity volume, white matter fractional anisotropy and mean diffusivity (measures of white matter integrity), and intracranial large artery stenosis. Participants underwent a battery of neurocognitive tests to obtain individual and global cognitive scores representative of various aspects of cognition. We included 85 participants (mean age 60 ± 6 years, 48% men, 78% non-Hispanic Black), most of them with well-controlled HIV (75% with CD4 cell count > 200 cells/mm3 and viral load < 400 copies/mL at or near the time of the MRI scan). Silent brain infarcts, intracranial large artery stenosis, and poor white matter integrity were associated with poorer performance in at least one cognitive domain, but the sum of these 3 MRI markers of CVD was associated with lower working memory (B = -0.213, P = 0.028), list learning (B = -0.275, P = 0.019), and global cognition (B = -0.129, P = 0.007). We identified silent brain infarcts, intracranial large artery stenosis, and poor white matter integrity as exposures that may be modifiable and may, therefore, influence cognitive decline. In addition, these MRI markers of CVD may help in identifying PLWH at higher risk of cognitive decline, which may be more amenable to targeted therapies.

Influence of Working Memory Capacity on the Frequency of Self-Repairs

This article explored the influence of working memory capacity on the frequency of self-repairs. The narrative task and listening span task were used. Twenty post-graduate students participated in this study. Overall, the results of this study illustrated that the working memory is a factor of self-repairs. Speakers who have higher working memory capacity produce lesser self-repairs. This finding provides teachers with a new insight into second language teaching; that is, teachers can improve the amount of lexical knowledge when teaching students who have lower working memory in order to help them produce more accurate language during the process of L2 speech production.

The Role of Working Memory on Writing Processes.

Literature has extensively demonstrated the coordination role of working memory (WM) in complex tasks such as writing. However, previous studies mostly concentrated on the relation between passive WM (e.g., WM span) components and specific writing tasks (e.g., dictation). Here, we aimed to investigate the relationship between different writing skills and the performance on a WM updating task measuring the more active components of WM. From a pool of 160 Italian pupils (grades 3–5), we selected 46 children divided in two groups based on their WM updating performance. The first group consisted of 21 children with low WM updating performance (≤10th percentile), the second group consisted of 25 children with high WM updating performance (≥90th percentile). All children were tested on a battery of writing tasks to assess writing speed, orthographic skills, and competences in expressive writing. MANOVAs and a discriminant analysis were computed to assess group differences and the contribution of the different writing tests in correctly predicting group membership. The results revealed that children with high WM updating performance scored significantly higher than children with low WM updating performance on most of the writing tasks. These results highlight the relevant role of the active components of WM on writing processes. In addition, they suggest that the improvement of writing skills should rely not only on the training of the specific processes implied in this complex task, but also on the training of the cognitive processes that support them, such as active WM processes.

The development of metacognitive accuracy in working memory across childhood.

Growth in working memory capacity, the number of items kept active in mind, is thought to be an important aspect of childhood cognitive development. Here, we focused on participants' awareness of the contents of their working memory, or meta-working memory, which seems important because people can put cognitive abilities to best use only if they are aware of their limitations. In two experiments on the development of meta-working memory in children between 6 and 13 years old and adults, participants were to remember arrays of colored squares and to indicate if a probe item was in the array. On many trials, before the probe recognition test, they reported a metajudgment, how many items they thought they remembered. We compared meta-working memory judgments to actual performance and looked for associations between these measures on individual and trial-by-trial levels. Despite much lower working memory capacity in younger children there was little change in meta-working memory judgments across age groups. Consequently, younger participants were much less realistic in their metajudgments concerning their working memory capability. Higher cognitive capacity was associated with more accurate meta-working memory judgments within an age group. Trial-by-trial tuning of metajudgments was evident only in young adults and then only for small array set sizes. In sum, meta-working memory ability is a sophisticated skill that develops with age and may be an integral aspect of the development of working memory across the school years. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Making the rich richer: Frontoparietal tDCS enhances transfer effects of a single-session distractor inhibition training on working memory in high capacity individuals but reduces them in low capacity individuals

Working memory (WM) performance depends on the ability to extract relevant while inhibiting irrelevant information from entering the WM storage. This distractor inhibition ability can be trained and is known to induce transfer effects on WM performance. Here we asked whether transfer on WM can be boosted by transcranial direct current stimulation (tDCS) during a single-session distractor inhibition training. As WM performance is ascribed to the frontoparietal network, in which prefrontal areas are associated with inhibiting distractors and posterior parietal areas with storing information, we placed the anode over the prefrontal and the cathode over the posterior parietal cortex during a single-session distractor inhibition training. This network-oriented stimulation protocol should enhance inhibition processes by shifting the neural activity from posterior to prefrontal regions. WM improved after a single-session distractor inhibition training under verum stimulation but only in subjects with a high WM capacity. In subjects with a low WM capacity, verum tDCS reduced the transfer effects on WM. We assume tDCS to strengthen the frontostriatal pathway in individuals with a high WM capacity leading to efficient inhibition of distractors. In contrast, the cathodal stimulation of the posterior parietal cortex might have hindered usual compensational mechanism in low capacity subjects, i.e. maintaining also irrelevant information in memory. Our results thus stress the need to adjust tDCS protocols to well-founded knowledge about neural networks and individual cognitive differences.

Contributions of HFE polymorphisms to brain and blood iron load, and their links to cognitive and motor function in healthy adults.

BackgroundBrain iron overload is linked to brain deterioration, and cognitive and motor impairment in neurodegenerative disorders and normal aging. Mutations in the HFE gene are associated with iron dyshomeostasis and are risk factors for peripheral iron overload. However, links to brain iron load and cognition are less consistent and data are scarce.Aims and methodsUsing quantitative susceptibility mapping with magnetic resonance imaging, we investigated whether C282Y and H63D contributed to aging‐related increases in brain iron load and lower cognitive and motor performance in 208 healthy individuals aged 20‐79 years. We also assessed the modulatory effects of HFE mutations on associations between performance and brain iron load, as well as peripheral iron metabolism.ResultsIndependent of age, carriers of either C282Y and/or H63D (HFE‐pos group, n = 66) showed a higher load of iron in putamen than non‐carriers (HFE‐neg group, n = 142), as well as higher transferrin saturation and lower transferrin and transferrin receptors in blood. In the HFE‐neg group, higher putaminal iron was associated with lower working memory. In the HFE‐pos group, higher putaminal iron was instead linked to higher executive function, and lower plasma transferrin was related to higher episodic memory. Iron‐performance associations were modest albeit reliable.ConclusionOur findings suggest that HFE status is characterized by higher regional brain iron load across adulthood, and support the presence of a modulatory effect of HFE status on the relationships between iron load and cognition. Future studies in healthy individuals are needed to confirm the reported patterns.

Working memory moderates the relation between implicit alcohol associations and heavy episodic drinking in moderate-to-heavy drinking men who have sex with men

IntroductionHeavy episodic drinking poses a risk for HIV-infection, particularly among men who have sex with men (MSM). Previous research suggests implicit associations may play a role in heavy episodic drinking and that various executive functions (EF) may moderate the relation between implicit associations and heavy episodic drinking. This study investigated the role of two EF – working memory (maintaining and updating information) and response inhibition (inhibiting prepotent responses) – as moderators of the relation between implicit alcohol approach associations and heavy episodic drinking among moderate-to-heavy drinking MSM. MethodsTwo-hundred and fifty-one participants completed measures of implicit alcohol associations (the implicit alcohol approach association test - IAT), working memory, and response inhibition, as well as a self-report questionnaire assessing heavy episodic drinking. Regression analyses were conducted to examine whether the association between the IAT and heavy episodic drinking was moderated by working memory and response inhibition. ResultsResults showed that working memory moderated the relation between the alcohol IAT and heavy episodic drinking such that IAT alcohol approach scores were positively associated with heavy episodic drinking among those low in working memory but not those high in working memory. Response inhibition did not moderate the association between IAT scores and heavy episodic drinking. ConclusionsResults suggest that the relation between implicit alcohol approach associations and heavy episodic drinking is stronger among moderate-to-heavy drinking MSM with lower working memory capacity compared to those with higher working memory capacity, and these individuals may particularly benefit from alcohol intervention approaches that target automatic alcohol responses.

Neural mechanisms and predictors of SSRI and CBT treatment of anxiety: A randomized trial focused on emotion and cognitive processing

Anxiety disorders (ADs) are common and difficult to treat. While research suggests ADs are characterized by an imbalance between bottom-up and top-down attention processes and that effective treatments work by correcting this dysfunction, there is insufficient data to explain how and for whom treatments work. The late positive potential (LPP), an event-related potential reflecting elaborative processing of motivationally salient stimuli, is sensitive to both bottom-up and top-down processes. The present study examines the LPP in healthy controls (HC) and patients with ADs under low and high working memory (WM) load to assess its utility as a predictor and index of symptom reduction in patients who underwent cognitive behavioral therapy (CBT) or selective serotonin reuptake inhibitor (SSRI) treatment. The LPP when viewing negative and neutral distractor images and WM performance were assessed in 96 participants (40 HC, 32 CBT, 24 SSRI) during a letter recall task at Week 0 and in a subset of the study sample (23 CBT, 16 SSRI) at Week 12. Patients were randomly assigned to twelve weeks of CBT or SSRI treatment. Participants completed self-reported symptom measures at each time point. Greater Week 0 LPP to negative images under low WM load predicted greater symptom reduction in the SSRI, but not the CBT, group. Regression analyses examining the LPP to negative images as an index of symptom reduction revealed a smaller decrease in the LPP to negative images under low WM load was associated with less anxiety reduction across treatment modalities. Findings suggest the LPP during low WM load may serve as a cost-effective predictor and index of treatment outcome in ADs.Clinical Trials Registration: ClinicalTrials.gov (Identifier: NCT01903447)

The association of WTELS as a master motivator with higher executive functioning and better mental health.

The goal is to test the validity of the “Will to exist-live and survive (WTELS) as a master motivator that activates executive functions. A sample of 262 adults administered different measures that included WTELS and executive functions. We conducted hierarchical regressions with working memory deficits (WMD) and inhibition deficits (ID) as dependent variables. We entered in the last steps resilience and WTELS as independent variables. We conducted path analysis with WTELS as independent variables and WMD and ID as outcome variables and resilience and social support as mediating variables. WTELS accounted for the high effect size for lower working memory deficits and medium effect size for lower inhibition deficits. In path analysis, the effects of WTELS on decreased WMD were direct, while its effects on the ID were indirect. PROCESS analysis indicated that WTELS was directly associated with lower depression, anxiety, PTSD, and COVID-19 traumatic stress, and its indirect effects were mediated by lower executive function deficits (Kira et al., Psych 12:992-1024 2021c, Kira et al., in press). The path model discussed was generally superior to the alternative models and was strictly invariant across genders (male/ female).Supplementary InformationThe online version contains supplementary material available at 10.1007/s12144-021-02078-8.

Age-related Differences in the Effects of Working Memory Capacity and Cognitive Load on Word Recognition: An Eye Tracking Study

Objectives: The purpose of the study was to identify the impact of age-related working memory capacity and cognitive load to word recognition using an eye tracker.Methods: A total of 48 participants (24 young, 24 elderly adults) who were divided according to working memory capacity (high, low) participated in the study. This study consisted of a digit load and word recognition task.Results: First, the elderly group had lower accuracy and slower response times than the young group. There was a significant difference between working memory capacity and cognitive load in response time. In the group with low working memory capacity, the response time increased under lower cognitive load, which was different from the group with a high working memory capacity. Next, the elderly group had a lower proportion of fixation than the young group by time interval. In addition, there was a significant interaction between group and cognitive load by time interval. In particular, the proportion of fixation decreased over time under a high cognitive load while the proportion of fixation increased under a low cognitive load in the elders, because the inhibition and switching abilities were weakened which made the elders unable to process information efficiently.Conclusion: The study results showed significant effects between working memory capacity and cognitive load in response time and proportion of fixation. This implies that complex factors influence language processing, which makes measuring accuracy insufficient. Thus, this research confirms the correlation among aging, working memory, and cognitive load through both online and offline measurement.

Tailoring explicit and implicit instruction methods to the verbal working memory capacity of students with special needs can benefit motor learning outcomes in physical education

This study examined the effects of explicit versus implicit instructions and feedback methods on motor learning and perceived competence of 9-to 13-year old students with special educational needs practicing a balancing task during physical education. The aim was to test if and how the effects of type of instruction and feedback methods were influenced by students' verbal and visuospatial working memory capacities. The students significantly increased their balancing performance and perceived competence from pre- to posttest, with no differences between groups. The relation between type of instruction and feedback methods and learning outcomes was significantly influenced by verbal working memory capacity, not by visuospatial working memory capacity. Physical education teachers may need to align their instructions with verbal working memory capacity, by providing implicit instructions and feedback methods in students with low verbal working memory capacity and explicit instruction and feedback methods in students with high verbal working memory capacity.