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Although working memory (WM) is amongst the most studied neurocognitive functions, temporal patterns of its component processes are not fully understood. We examined the neural underpinnings of active maintenance and interference management in the n-back task by manipulating load (1-back vs 3-back) and including so-called lure stimuli. ERPs of 27 young adults revealed that the 1-back condition enabling active maintenance showed a positive slow wave (PSW) prior to the next stimulus (-600-0 ms) and augmented P2 (190-290 ms) and P3b (330-430 ms) responses after the stimulus appeared, albeit the latter effects were driven by the initial PSW. Moreover, PSW amplitude correlated negatively with reaction time in the 1-back condition. Responses to lures showed interference, accompanied with different ERP effects for the two load levels. Our results support the view that PSW reflects efficient WM maintenance and suggest two distinct neuronal correlates for interference in WM., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The efficacy of working memory (WM) training has been a controversial and hotly debated issue during the past years. Despite a large number of training studies and several meta-analyses, the matter has not yet been solved. We conducted a multi-level meta-analysis on the cognitive transfer effects in healthy adults who have been administered WM updating training with n-back tasks, the most common experimental WM training paradigm. Thanks to this methodological approach that has not been employed in previous meta-analyses in this field, we were able to include effect sizes from all relevant tasks used in the original studies. Altogether 203 effect sizes were derived from 33 published, randomized, controlled trials. In contrast to earlier meta-analyses, we separated task-specific transfer (here untrained n-back tasks) from other WM transfer tasks. Two additional cognitive domains of transfer that we analyzed consisted of fluid intelligence (Gf) and cognitive control tasks. A medium-sized transfer effect was observed to untrained n-back tasks. For other WM tasks, Gf, and cognitive control, the effect sizes were of similar size and very small. Moderator analyses showed no effects of age, training dose, training type (single vs. dual), or WM and Gf transfer task contents (verbal vs. visuospatial). We conclude that a substantial part of transfer following WM training with the n-back task is task-specific and discuss the implications of the results to WM training research.

The present study investigated the effect of bilingualism on the two widely used developmental neuropsychological test batteries Wechsler Intelligence Scale for Children - Fourth Edition (WISC-IV) and A Developmental Neuropsychological Assessment, Second Edition (NEPSY-II) in children. The sample consisted of 100 Finland-Swedish children in two age groups. About half (n = 52) of the participants were early simultaneous bilinguals, and the other half (n = 48) were monolinguals. As no Finland-Swedish versions of the tests are available at the moment, both tests were translated and adapted to suit this population. The results revealed no difference in the performance between bilingual and monolingual children. This speaks against a cognitive advantage in bilingual children and indicates that development of separate norms for monolingual and bilingual children is not needed for clinical use.

Studies have indicated that video gaming is positively associated with cognitive performance in select cognitive domains, but the magnitudes of these associations have been called into question, as they have frequently been based on extreme groups analyses that have compared video gamers with non-gamers. When including the whole range of participants, and not just extreme cases, these effects were observed to reduce markedly (Unsworth et al., 2015). To further study this issue, we compared the associations between video gaming and aspects of working memory (WM) performance in an extreme groups design to those of a design that includes the full range of participants in a large adult sample (n = 503). WM was measured with three composite scores (verbal WM, visuospatial WM, n-back). The extreme groups analyses showed that video gamers performed better than non-gamers on all three WM measures, while the whole sample analyses indicated weak positive associations between the time spent playing video games and visuospatial WM and n-back performance. Thus, study design modulated the effects, but two of the three associations between WM and video gaming were consistent across both analysis techniques. A separate study confirmed that our questionnaire-based estimate of gaming hours was reliable when compared with one-week diaries of videogame playing. While the present cross-sectional results preclude causal inferences, possible mechanisms of WM - videogame playing associations and future research directions are discussed. Overall, our results indicate that cognition - videogame playing relationships, albeit weak, are not solely due to recently discussed methodological artefacts concerning the particular analytical approach and survey reliability.

Clinical anxiety and acute stress caused by major life events have well-documented detrimental effects on cognitive processes, such as working memory (WM). However, less is known about the relationships of state anxiety or everyday stress with WM performance in non-clinical populations. We investigated the associations between these two factors and three WM composites (verbal WM, visuospatial WM, and n-back updating performance) in a large online sample of non-depressed US American adults. We found a trend for a negative association between WM performance and anxiety, but not with stress. Thus, WM performance appears rather robust against normal variation in anxiety and everyday stress. [ABSTRACT FROM AUTHOR]

The bilingual executive advantage (BEA) hypothesis has attracted considerable research interest, but the findings are inconclusive. We addressed this issue in the domain of working memory (WM), as more complex WM tasks have been underrepresented in the previous literature. First, we compared early and late bilingual vs. monolingual WM performance. Second, we examined whether certain aspects of bilingual experience, such as language switching frequency, are related to bilinguals’ WM scores. Our online sample included 485 participants. They filled in an extensive questionnaire including background factors such as bilingualism and second language (L2) use, and performed 10 isomorphic verbal and visuospatial WM tasks that yielded three WM composite scores (visuospatial WM, verbal WM, n-back). For verbal and visuospatial WM composites, the group comparisons did not support the BEA hypothesis. N-back analysis showed an advantage of late bilinguals over monolinguals and early bilinguals, while the latter two groups did not differ. This between-groups analysis was followed by a regression analysis relating features of bilingual experience to n-back performance, but the results were non-significant in both bilingual groups. In sum, group differences supporting the BEA hypothesis were limited only to the n-back composite, and this composite was not predicted by bilingualism-related features. Moreover, Bayesian analyses did not give consistent support for the BEA hypothesis. Possible reasons for the failure to find support for the BEA hypothesis are discussed. [ABSTRACT FROM AUTHOR]

Previous studies that have investigated associations between working memory (WM) and the Big Five personality traits have yielded mixed results, with some finding statistically significant associations while others have not. The aim of the current study was twofold. First, we systematically reviewed previous studies on WM-Big Five associations. Second, we investigated associations between three WM composites (numerical-verbal WM, visuospatial WM, n-back) and the Big Five in a large-scale study on adults ( n  = 503). Here we controlled for possible confounding caused by the way WM is operationalized, the content domain of the WM tasks (verbal vs. spatial), and sample size. The systematic review revealed that the majority of earlier studies show no association between any of the personality traits and WM performance. As regards our empirical study, the only significant associations were the negative correlations between n-back WM updating performance and the Conscientiousness and Openness traits. This means that the more Conscientious or Open to experiences a participant reported being, the worse was the n-back performance. Overall, our study failed to show any robust relationships between WM performance and the Big Five personality traits. We discuss possible reasons for these findings. [ABSTRACT FROM AUTHOR]

During the past decade, working memory training has attracted much interest. However, the training outcomes have varied between studies and methodological problems have hampered the interpretation of results. The current study examined transfer after working memory updating training by employing an extensive battery of pre-post cognitive measures with a focus on near transfer. Thirty-one healthy Finnish young adults were randomized into either a working memory training group or an active control group. The working memory training group practiced with three working memory tasks, while the control group trained with three commercial computer games with a low working memory load. The participants trained thrice a week for five weeks, with one training session lasting about 45 minutes. Compared to the control group, the working memory training group showed strongest transfer to an n-back task, followed by working memory updating, which in turn was followed by active working memory capacity. Our results support the view that working memory training produces near transfer effects, and that the degree of transfer depends on the cognitive overlap between the training and transfer measures. [ABSTRACT FROM AUTHOR]

Background: Language performance in aphasia can vary depending on several variables such as stimulus characteristics and task demands. This study focuses on the degree of verbal working memory (WM) load inherent in the language task and how this variable affects language performance by individuals with aphasia. Aims: The first aim was to identify the effects of increased verbal WM load on the performance of judgements of semantic similarity (synonymy) and phonological similarity (rhyming). The second aim was to determine if any of the following abilities could modulate the verbal WM load effect: semantic or phonological access, semantic or phonological short-term memory (STM), and any of the following executive processing abilities: inhibition, verbal WM updating, and set shifting. Method & Procedures: A total of 31 individuals with aphasia and 11 controls participated in this study. They were administered a synonymy judgement task and a rhyming judgement task under high and low verbal WM load conditions that were compared to each other. In a second set of analyses multiple regression was used to identify which factors (as noted above) modulated the verbal WM load effect. Outcomes & Results: For participants with aphasia, increased verbal WM load significantly reduced accuracy of performance on synonymy and rhyming judgements. Better performance in the low verbal WM load conditions was evident even after correcting for chance. The synonymy task included concrete and abstract word triplets. When these were examined separately the verbal WM load effect was significant for the abstract words, but not the concrete words. The same pattern was observed in the performance of the control participants. Additionally, the second set of analyses revealed that semantic STM and one executive function, inhibition ability, emerged as the strongest predictors of the verbal WM load effect in these judgement tasks for individuals with aphasia. Conclusions: The results of this study have important implications for diagnosis and treatment of aphasia. As the roles of verbal STM capacity, executive functions and verbal WM load in language processing are better understood, measurements of these variables can be incorporated into our diagnostic protocols. Moreover, if cognitive abilities such as STM and executive functions support language processing and their impairment adversely affects language function, treating them directly in the context of language tasks should translate into improved language function. [ABSTRACT FROM AUTHOR]

• Strategies generated during training predict training gains. • These self-generated strategies stabilize early on. • Externally given strategy elicits only fleeting training task gain. • Working memory training represents cognitive skill learning. Cognitive mechanisms underlying the limited transfer effects of working memory (WM) training remain poorly understood. We tested in detail the Strategy Mediation hypothesis, according to which WM training generates task-specific strategies that facilitate performance on the trained task and its untrained variants. This large-scale pre-registered randomized controlled trial (n = 258) used a 4-week adaptive WM training with a single digit n-back task. Strategy use was probed with open-ended strategy reports. We employed a Strategy training group (n = 73) receiving external strategy instruction, a Traditional training group (n = 118) practicing without strategy instruction, and Passive controls (n = 67). Both training groups showed emerging transfer to untrained n-back task variants already at intermediate test after 3 training sessions, extending to all untrained n-back task variants at posttest after 12 training sessions. The Strategy training group outperformed the Traditional training group only at the beginning of training, indicating short-lived strategy manipulation effects. Importantly, in the Traditional training group, strategy evolvement modulated the gains in the trained and untrained n-back tasks, supporting the Strategy Mediation hypothesis. Our results concur with the view of WM training as cognitive skill learning. [ABSTRACT FROM AUTHOR]