Transfer of working memory training to the inhibitory control of auditory distraction

Optimizing working memory assessment: development of shortened versions of complex spans, updating, and binding tasks

Given the lengthy administration of most working memory (WM) tasks, some researchers have developed reduced versions of these tests. However, they have focused primarily on complex spans. Recent studies suggested that estimating working memory capacity (WMC) using multiple tasks from different paradigms enhances measurement accuracy by isolating WMC variation from task- and paradigm-specific influences. Considering this, we evaluated whether complex spans, updating, and binding tasks could be shortened while maintaining robust psychometric properties. Participants completed full-length versions of tests from these paradigms, which were then segmented into early, intermediate, and later trial blocks. The shortened WM tasks were based on the early trial blocks. They accounted for most of the variance in a set of factor scores derived from the full-length versions of the WM tests (R2 = 0.90). Additionally, the shortened and full-length versions presented a similar ability to predict fluid intelligence (Gf). The shortened tasks reduced administration time by 35%, saving around 30 min. To help researchers select the most suitable combination of shortened and/or full-length tasks, we calculated the Gf and WMC variance predicted by every possible task combination and the respective administration time. We believe that the shortened WM tasks will be highly valuable to researchers, as they provide reliable and valid WMC estimates in a time-efficient manner. We also examined whether using tests from different paradigms provides better WMC estimates than employing collections of tasks from the same class. Our results confirmed this hypothesis, highlighting the importance of diverse task selection to accurately assess WMC.

A comparison of Barkley's behavioral inhibition model (1997) with Barkley's updated executive functioning model in predicting adult ADHD symptoms: A preliminary report using structural equation modeling

One of the most comprehensive approaches to explaining attention-deficit/hyperactivity disorder (ADHD) symptoms is Barkley's behavioral inhibition model (BBIM) (1997), in which behavioral inhibition (BI) plays a primary role. Due to the substantial role of working memory (WM) in explaining ADHD symptoms, Barkley recently updated his model and elevated WM from a mediator variable (in BBIM) to a primary position as an exogenous variable alongside BI, and titled his new model as Barkley's updated executive functioning model (BUEFM). However, since the information about the explanatory power of the new model is sparse, this study aims to investigate the impact of this change in WM role by comparing these two models to explain ADHD symptoms. The study involved a sample of 184 (96 females and 88 males) undergraduate students with high ADHD symptoms who were selected using the purposive sampling method. For assessing models, we have utilized four tools that include: CNS-Vital Sign Test Battery; Barkley Deficit in Executive Functioning Scale; self-verbalization questionnaire (SVQ); and trail making test. We analyzed the data by running structural equation modeling (SEM) analysis using IBM AMOS software version 22. The results show that Model Comparison Measurement (e.g. AIC was 197.583 and 144.614 for BBIM and BUEFM, respectively) and Model Fit Indices (e.g. root mean square error of approximation (RMSEA) obtained 0.076 and 0.067 for BBIM and BUEFM, respectively) representing that BUEFM had a better value than BBIM, which means that the BUEFM was considered better fitting to the data. The findings of this study show that BUEFM has more Predictive power than BBIM to predict symptoms of ADHD through the motor control fluency (MOT) variable.

When softer sounds are more distracting: Task-irrelevant whispered speech causes disruption of serial recall

Two competing accounts propose that the disruption of short-term memory by irrelevant speech arises either due to interference-by-process (e.g., changing-state effect) or attentional capture, but it is unclear how whispering affects the irrelevant speech effect. According to the interference-by-process account, whispered speech should be less disruptive due to its reduced periodic spectro-temporal fine structure and lower amplitude modulations. In contrast, the attentional account predicts more disruption by whispered speech, possibly via enhanced listening effort in the case of a comprehended language. In two experiments, voiced and whispered speech (spoken sentences or monosyllabic words) were presented while participants memorized the order of visually presented letters. In both experiments, a changing-state effect was observed regardless of the phonation (sentences produced more disruption than "steady-state" words). Moreover, whispered speech (lower fluctuation strength) was more disruptive than voiced speech when participants understood the language (Experiment 1), but not when the language was incomprehensible (Experiment 2). The results suggest two functionally distinct mechanisms of auditory distraction: While changing-state speech causes automatic interference with seriation processes regardless of its meaning or intelligibility, whispering appears to contain cues that divert attention from the focal task primarily when presented in a comprehended language, possibly via enhanced listening effort.

Can we enhance working memory? Bias and effectiveness in cognitive training studies

Meta-analyses have found that working memory (WM) can be improved with cognitive training; however, some authors have suggested that these improvements are mostly driven by biases in the measurement of WM, especially the use of similar tasks for assessment and training. In the present meta-analysis, we investigated whether WM, fluid intelligence, executive functions, and short-term memory can be improved by cognitive training and evaluated the impact of possible sources of bias. We performed a risk of bias assessment of the included studies and took special care in controlling for practice effects. Data from 52 independent comparisons were analyzed, including cognitive training aimed at different cognitive functions. Our results show small improvements in WM after training (SMD = 0.18). Much larger effects were observed when the analysis was restricted to assessment tasks similar to those used for training (SMD = 1.15). Fluid intelligence was not found to improve as a result of training, and improvements in WM were not related to changes in fluid intelligence. Our analyses did however indicate that cognitive training can improve specific executive functions. Contrary to expectations, a set of meta-regressions indicated that characteristics of the training programme, such as dosage and type of training, do not have an impact on the effectiveness of training. The risk of bias assessment revealed some concerns in the randomization process and possible selective reporting among studies. Overall, our results identified various potential sources of bias, with the most significant being the choice of assessment tasks.

Working memory and inhibitory control deficits in children with ADHD: an experimental evaluation of competing model predictions

Introduction

Children with ADHD demonstrate difficulties on many different neuropsychological tests. However, it remains unclear whether this pattern reflects a large number of distinct deficits or a small number of deficit(s) that broadly impact test performance. The current study is among the first experiments to systematically manipulate demands on both working memory and inhibition, with implications for competing conceptual models of ADHD pathogenesis.

Method

A clinically evaluated, carefully phenotyped sample of 110 children with ADHD, anxiety disorders, or co-occurring ADHD+anxiety (Mage=10.35, 44 girls; 69% White Not Hispanic/Latino) completed a counterbalanced, double dissociation experiment, with two tasks each per inhibition (low vs. high) x working memory (low vs. high) condition.

Results

Bayesian and frequentist models converged in indicating that both manipulations successfully increased demands on their target executive function (BF10>5.33x108, p<.001). Importantly, occupying children's limited capacity working memory system produced slower response times and reduced accuracy on inhibition tasks (BF10>317.42, p<.001, d=0.67-1.53). It also appeared to differentially reduce inhibition (and non-inhibition) accuracy for children with ADHD relative to children with anxiety (BF10=2.03, p=.02, d=0.50). In contrast, there was strong evidence against models that view working memory deficits as secondary outcomes of underlying inhibition deficits in ADHD (BF01=18.52, p=.85).

Discussion

This pattern indicates that working memory broadly affects children's ability to inhibit prepotent tendencies and maintain fast/accurate performance, and may explain the errors that children with ADHD make on inhibition tests. These findings are broadly consistent with models describing working memory as a causal mechanism that gives rise to secondary impairments. In contrast, these findings provide evidence against models that view disinhibition as a cause of working memory difficulties or view working memory as a non-causal correlate or epiphenomenon in ADHD.

Joint action with human and robotic co-actors: Self-other integration is immune to the perceived humanness of the interacting partner

When performing a joint action task, we automatically represent the action and/or task constraints of the co-actor with whom we are interacting. Current models suggest that, not only physical similarity, but also abstract, conceptual features shared between self and the interacting partner play a key role in the emergence of joint action effects. Across two experiments, we investigated the influence of the perceived humanness of a robotic agent on the extent to which we integrate the action of that agent into our own action/task representation, as indexed by the Joint Simon Effect (JSE). The presence (vs. absence) of a prior verbal interaction was used to manipulate robot's perceived humanness. In Experiment 1, using a within-participant design, we had participants perform the joint Go/No-go Simon task with two different robots. Before performing the joint task, one robot engaged in a verbal interaction with the participant and the other robot did not. In Experiment 2, we employed a between-participants design to contrast these two robot conditions as well as a human partner condition. In both experiments, a significant Simon effect emerged during joint action and its amplitude was not modulated by the humanness of the interacting partner. Experiment 2 further showed that the JSE obtained in robot conditions did not differ from that measured in the human partner condition. These findings contradict current theories of joint action mechanisms according to which perceived self-other similarity is a crucial determinant of self-other integration in shared task settings.

Exploring the Effectiveness of Group Cognitive Stimulation Training in People With Schizophrenia: A Randomized Controlled Trial

BACKGROUND

Schizophrenia is a chronic degenerative brain disease. Cognitive impairment, the core symptom of this disease, affects the mood and social functioning of patients severely. Nonpharmacological therapies that both improve cognitive function and are suitable for patients with schizophrenia remain underdeveloped.

PURPOSE

This article was designed to explore the effects of group cognitive stimulation training (GCST) on cognitive function and social function in people with schizophrenia.

METHODS

A randomized controlled trial was conducted. The 76 participants were allocated into either the experimental or control group using blocked randomization. The participants were all patients with chronic schizophrenia recruited from seven rehabilitation units in northern Taiwan who were 20-65 years old and scored 10-25 on the Montreal Cognitive Assessment Taiwan Version. The experimental group received the 60-minute GCST twice a week for 7 weeks, whereas the control group received standard treatment. All outcome indicators were analyzed at baseline and after intervention using generalized estimating equations. The primary outcome indicators included cognitive function assessed using the Taiwan version of the Montreal Cognitive Assessment, working memory assessed using the Wechsler Memory Scale-Third Edition, and executive function assessed using the Taiwanese version of the Frontal Assessment Battery. The secondary outcome indicator was social function assessed using the Social Function Scale-Taiwan short version.

RESULTS

Generalized estimating equation modeling revealed the experimental group exhibited significant improvement in Montreal Cognitive Assessment total score ( B = 1.33, SE = 0.65, p = .040) and Social Function Scale-Taiwan short version ( B = 9.55, SE = 2.38, p < .001) after adjusting for nine covariates. No significant differences between the two groups in terms of working memory ( B = 4.79, SE = 2.66, p = .071) or executive function ( B = 0.53, SE = 0.63, p = .399) were found.

CONCLUSIONS/IMPLICATIONS FOR PRACTICE

The results indicate that GCST positively impacts overall cognitive and social functions but not higher-order cognitive function (working memory and executive function). In clinical settings, GCST may be applied to improve cognitive function in people with schizophrenia. The findings of this study may inform the practice of mental health nurses to improve cognitive function in patients in clinical care.

Unconscious priming shares a common resource pool with the manipulation subsystem

Background

Working memory can be subdivided into two relatively independent subordinate systems, the maintenance subsystem and the manipulation subsystem. Although the two subsystems are quite heterogeneous, research thus far has not adequately distinguished the resource pools of the two subsystems. Additionally, previous research on the relationship between working memory and unconscious priming is paradoxical. Different subsystems leading to different effects on unconscious priming might be the reason for the paradoxical research. Therefore, the current article aimed to distinguish the resource pools among two working-memory subsystems and to investigate the relationship between the two subsystems and unconscious priming.

Methods

To address these issues, a maintenance dual-task and a manipulation dual-task program were developed. Each participant had to separately perform the two dual tasks in a balanced order. In each dual task, participants first completed a masked priming task accompanied by working-memory load. As a control, participants completed a prime identification test to confirm that the processing of the masked prime was at the unconscious level. The maintenance dual task comprised sandwich masking trials accompanied by Sternberg trials, while the manipulation dual task comprised sandwich masking trials accompanied by N-back trials.

Results

The results of the prime identification test indicated that the participants could not consciously perceive the masked prime of both dual tasks. The results of the working-memory task of both dual tasks indicated that the load manipulation was successful for both dual tasks. Most importantly, the results of the masking task of both dual tasks showed that an increase in working-memory load decreased the magnitude of unconscious priming in the manipulation dual task, whereas an increase in working-memory load did not decrease unconscious priming in the maintenance dual task. These observations demonstrate that the manipulation subsystem, rather than the maintenance subsystem, interferes with unconscious priming. Together with previous research, we propose a two-pool attention resource model to explain the modulation of working memory on unconscious priming by dissociating the executive resource pool of the manipulation system from the retention resource pool of the maintenance system. Thus, the current work confirms and extends the extant literature about the dependence of unconscious processing on attention resources by suggesting that unconscious priming shares a common resource pool with the manipulation subsystem.

Working memory training does not improve executive functioning or fluid intelligence

Several studies have reported that cognitive training can lead to improvements of complex mental skills such as intelligence. However, attempts to replicate these findings have not been very successful with many studies reporting lack of transferable effects on cognitive processes unrelated to the training task. On the contrary, transfer effects on cognitive processes closely related to the training task have been more commonly reported. In this study, we investigated the effects of a frequently used working-memory training programme on fluid intelligence and specific executive functions (updating, inhibition, switching, the focus of attention, and sustained attention). We remedied common issues with previous training studies by using an active control group, using more than one instrument to assess each function, and including a larger sample size. The experimental group showed significant improvement in the training task, indicating strong practice effects. However, no evidence of training-specific transfer was found in any of the variables investigated, and we could not find any of the previous improvements reported. Participants in both the training and control groups showed post-training improvements in most of the outcome variables, suggesting that practice effects can be found even when a task is only performed twice. We conclude by discussing possible explanations for the differences between our results and those reported in prior studies and recommend that any claims of improvement should be supported by studies capable of replicating them.