A computational model of prefrontal and striatal interactions in perceptual category learning.

Work on multiple-system theories of cognition mostly focused on the systems themselves, while limited work has been devoted to understanding the interactions between systems. Generally, multiple-system theories include a model-based decision system supported by the prefrontal cortex and a model-free decision system supported by the striatum. Here we propose a neurobiological model to describe the interactions between model-based and model-free decision systems in category learning. The proposed model used spiking neurons to simulate activity of the hyperdirect pathway of the basal ganglia. The hyperdirect pathway acts as a gate for the response signal from the model-free system located in the striatum. We propose that the model-free system's response is inhibited when the model-based system is in control of the response. The new model was used to simulate published data from young adults, people with Parkinson's disease, and aged-matched older adults. The simulation results further suggest that system-switching ability may be related to individual differences in executive function. A new behavioral experiment tested this model prediction. The results show that an updating score predicts the ability to switch system in a categorization task. The article concludes with new model predictions and implications of the results for research on system interactions.

The role of proactive interference in working memory training and transfer.

Recent work on working memory training has produced conflicting results regarding the degree and generality of transfer to other cognitive processes. However, few studies have investigated possible mechanisms underlying transfer. The current study was designed to test the role of proactive interference in working memory training and transfer. Eighty-six young adults participated in a pretest-posttest design, with ten training sessions in between. In the two working memory training conditions, subjects performed an operation span task, with one condition requiring recall of letters on every trial (operation-letters), whereas the other condition alternated between letters, digits, and words as the to-be-remembered items across trials (operation-mix). These groups were compared to an active-control group (visual-search). Working memory, verbal fluency, and reading comprehension measures were administered in pretest and posttest sessions. All groups significantly increased their performance over the ten training sessions. There was evidence of strategy-specific benefits on transfer, such that transfer to working memory measures was higher for the operation-letters group on tasks specifically involving letters, and no differential transfer to working memory tests without letters, to verbal fluency, or to reading comprehension. The results indicate that proactive interference does not appear to play a causal role in determining transfer from working memory training, and instead a strategy account based on stimulus content provides a more parsimonious explanation for the pattern of training and transfer.

Task manipulation effects on the relationship between working memory and go/no-go task performance.

Go/no-go tasks are widely used in psychology as measures of inhibition, mind-wandering, and impulsivity, but relatively little research has explored the impact that task manipulations have on task performance and measurement of the intended psychological constructs. Experiment 1 investigated the differences between perceptual and semantic versions of go/no-go tasks and how task performance relates to individual differences in working memory capacity (WMC), a widely-studied cognitive construct. The type of decision performed on the go/no-go stimuli influenced performance, but not the relationship with WMC. Experiment 2 examined the potential of inter-stimulus interval (ISI), which influenced go/no-go performance, along with the relationships with WMC. However, the type of decision had effects on performance above and beyond that of the ISI. The results are discussed in relation to the psychological literature using go/no-go tasks as behavioral indices of inhibition and mind-wandering, and in the context of previous investigations of individual differences in WMC.

Predictors of Effective Working Memory Training in Individuals with Alcohol Use Disorders.

BACKGROUND: Low working memory (WM) capacity is associated with alcohol use disorders (AUDs). The importance of WM to adaptive functioning has led to a recent influx of studies attempting to improve individual WM capacity using various cognitive training methods. The present study aimed to examine the efficacy of complex WM training for improving WM capacity among individuals with AUD. METHODS: Individuals were randomized to complete either adaptive WM training or active control training. We applied a methodologically rigorous and structured approach, including a battery of near and moderate transfer measures in those with AUDs and a control group. Additionally, we examined cognitive factors (at baseline) and other predictors of adherence, training task improvement, and transfer. RESULTS: Results suggest improved WM in individuals with AUDs and controls, as evidenced by improved scores on several transfer measures, after adaptive WM training. However, individuals with AUDs showed poorer adherence and less improvement on the training tasks themselves. Neither IQ, WM, sex, nor condition predicted adherence. Level of training task performance, baseline WM, and IQ predicted transfer task improvement. CONCLUSIONS: This is the first study to rigorously examine both the efficacy of WM training in those with AUDs, and predictors of successful training program adherence and transfer in a large sample. Among study completers, results suggest that AUD status does not predict training improvement and transfer. However, AUD status did predict lower program adherence. WM training was more effective in those with higher cognitive ability at baseline. This study provides direct translation to the development of cognitive interventions for treating AUD.

Is playing video games related to cognitive abilities?

The relations between video-game experience and cognitive abilities were examined in the current study. In two experiments, subjects performed a number of working memory, fluid intelligence, and attention-control measures and filled out a questionnaire about their video-game experience. In Experiment 1, an extreme-groups analysis indicated that experienced video-game players outperformed nonplayers on several cognitive-ability measures. However, in Experiments 1 and 2, when analyses examined the full range of subjects at both the task level and the latent-construct level, nearly all of the relations between video-game experience and cognitive abilities were near zero. These results cast doubt on recent claims that playing video games leads to enhanced cognitive abilities. Statistical and methodological issues with prior studies of video-game experience are discussed along with recommendations for future studies.

Shortened complex span tasks can reliably measure working memory capacity.

Measures of working memory capacity (WMC), such as complex span tasks (e.g., operation span), have become some of the most frequently used tasks in cognitive psychology. However, due to the length of time it takes to complete these tasks many researchers trying to draw conclusions about WMC forgo properly administering multiple tasks. But can the complex span tasks be shortened to take less administration time? We address this question by splitting the tasks into three blocks of trials, and analyzing each block's contribution to measuring WMC and predicting fluid intelligence (Gf). We found that all three blocks of trials contributed similarly to the tasks' ability to measure WMC and Gf, and the tasks can therefore be substantially shortened without changing what they measure. In addition, we found that cutting the number of trials by 67 % in a battery of these tasks still accounted for 90 % of the variance in their measurement of Gf. We discuss our findings in light of administering the complex span tasks in a method that can maximize their accuracy in measuring WMC, while minimizing the time taken to administer.

The development of a short domain-general measure of working memory capacity.

Working memory capacity is one of the most frequently measured individual difference constructs in cognitive psychology and related fields. However, implementation of complex span and other working memory measures is generally time-consuming for administrators and examinees alike. Because researchers often must manage the tension between limited testing time and measuring numerous constructs reliably, a short and effective measure of working memory capacity would often be a major practical benefit in future research efforts. The current study developed a shortened computerized domain-general measure of working memory capacity by representatively sampling items from three existing complex working memory span tasks: operation span, reading span, and symmetry span. Using a large archival data set (Study 1, N = 4,845), we developed and applied a principled strategy for developing the reduced measure, based on testing a series of confirmatory factor analysis models. Adequate fit indices from these models lent support to this strategy. The resulting shortened measure was then administered to a second independent sample (Study 2, N = 172), demonstrating that the new measure saves roughly 15 min (30%) of testing time on average, and even up to 25 min depending on the test-taker. On the basis of these initial promising findings, several directions for future research are discussed.

Working memory training may increase working memory capacity but not fluid intelligence.

Working memory is a critical element of complex cognition, particularly under conditions of distraction and interference. Measures of working memory capacity correlate positively with many measures of real-world cognition, including fluid intelligence. There have been numerous attempts to use training procedures to increase working memory capacity and thereby performance on the real-world tasks that rely on working memory capacity. In the study reported here, we demonstrated that training on complex working memory span tasks leads to improvement on similar tasks with different materials but that such training does not generalize to measures of fluid intelligence.

The scope and control of attention as separate aspects of working memory.

The present study examines two varieties of working memory (WM) capacity task: visual arrays (i.e., a measure of the amount of information that can be maintained in working memory) and complex span (i.e., a task that taps WM-related attentional control). Using previously collected data sets we employ confirmatory factor analysis to demonstrate that visual arrays and complex span tasks load on separate, but correlated, factors. A subsequent series of structural equation models and regression analyses demonstrate that these factors contribute both common and unique variance to the prediction of general fluid intelligence (Gf). However, while visual arrays does contribute uniquely to higher cognition, its overall correlation to Gf is largely mediated by variance associated with the complex span factor. Thus we argue that visual arrays performance is not strictly driven by a limited-capacity storage system (e.g., the focus of attention; Cowan, 2001), but may also rely on control processes such as selective attention and controlled memory search.

The Effects of Working Memory versus Adaptive Visual Search Control Training on Executive Cognitive Function.

There is considerable debate about whether Working Memory (WM) training specifically results in far-transfer improvements in executive cognitive function (ECF) rather than improvements on tasks similar to the training tasks. There has also been recent interest in whether WM training can improve ECF in clinical populations with clear deficits in ECFs. The current study examined the effects of WM training compared with non-WM adaptive Visual Search (VS) control training (15 sessions over 4 weeks) on various measures of ECF, including delay discounting (DD) rate, inhibition on flanker, color and spatial Stroop tasks, and drinking in a community-recruited sample with Alcohol Use Disorder (AUD, 41 men, 41 women, mean age = 21.7 years), who were not in treatment or seeking treatment, and non-AUD healthy controls (37 men, 52 women, mean age = 22.3 years). Both WM and VS training were associated with improvements on all ECF measures at 4 weeks and 1-month follow-up. WM and VS training were associated with reductions in both DD rates and interference on Stroop and Flanker tasks in all participants, as well as reductions in drinking in AUD participants that remained apparent one month post training. The results suggest that nonspecific effects of demanding cognitive training, as opposed to specific WM training effects, could enhance ECF, and that such enhancements are retained at least one-month post-training.

The role of maintenance and disengagement in predicting reading comprehension and vocabulary learning.

This study uses a novel framework based on work by Shipstead, Harrison, and Engle (2016) that includes measures of both working memory capacity and fluid intelligence in an attempt to better understand the processes that influence successful reading comprehension at the latent level. Further, we extend this framework to a second educationally relevant ability: second-language vocabulary learning. A large sample of young adults received a battery of working memory, fluid intelligence, language comprehension, and memory updating tasks. The results indicate that individual differences in reading comprehension and vocabulary learning benefit from the ability to maintain active information, as well as to disengage from no longer relevant information. Subsequently, we provide an interpretation of our results based on the maintenance and disengagement framework proposed by Shipstead et al. (2016). (PsycINFO Database Record (c) 2019 APA, all rights reserved).

CNTRICS final task selection: working memory.

The third meeting of the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) was focused on selecting promising measures for each of the cognitive constructs selected in the first CNTRICS meeting. In the domain of working memory, the 2 constructs of interest were goal maintenance and interference control. CNTRICS received 3 task nominations for each of these constructs, and the breakout group for working memory evaluated the degree to which each of these tasks met prespecified criteria. For goal maintenance, the breakout group for working memory recommended the AX-Continuous Performance Task/Dot Pattern Expectancy task for translation for use in clinical trial contexts in schizophrenia research. For interference control, the breakout group recommended the recent probes and operation/symmetry span tasks for translation for use in clinical trials. This article describes the ways in which each of these tasks met the criteria used by the breakout group to recommend tasks for further development.

Complex working memory span tasks and higher-order cognition: a latent-variable analysis of the relationship between processing and storage.

Complex span tasks, assumed by many to measure an individual's working memory capacity, are predictive of several aspects of higher-order cognition. However, the underlying cause of the relationships between "processing-and-storage" tasks and cognitive abilities is still hotly debated nearly 30 years after the tasks were first introduced. The current study utilised latent constructs across verbal, numerical, and spatial content domains to examine a number of questions regarding the predictive power of complex span tasks. In particular, the relations among processing time, processing accuracy, and storage accuracy from the complex span tasks were examined, in combination with their respective relationships with fluid intelligence. The results point to a complicated pattern of unique and shared variance among the constructs. Implications for various theories of working memory are discussed.

The Hype Cycle of Working Memory Training.

Seventeen years and hundreds of studies after the first working memory training journal article was published, evidence for the efficacy of working memory training is still wanting. Numerous studies show that individuals who repeatedly practice computerized working memory tasks improve on those tasks and closely related variants. Critically, although individual studies have claimed improvements in untrained abilities and behaviors, systematic reviews of the broader literature show that studies producing large, positive findings are often those with the most methodological shortcomings. The current review discusses the past, present, and future status of working memory training, including consideration of factors that might influence working memory training and transfer efficacy.

The influence of thought probes on performance: Does the mind wander more if you ask it?

Mind-wandering has emerged in the past decade as a popular topic in many areas of psychological research. Numerous studies have demonstrated the potential costs and benefits of mind-wandering in relation to ongoing task performance, along with more recent work examining the nature of different types of mind-wandering. A common method of measuring mind-wandering in laboratory research is to embed self-report thought probes at random intervals within an ongoing task. However, a critical issue to determine is whether or not the presence of the thought probes fundamentally alters how an individual typically performs on the task. In the current study, N = 149 participants completed a sustained attention to response task (SART) with and without the presence of mind-wandering thought probes. In addition, participants completed operation and symmetry span measures of working memory capacity, as several studies have examined the relationship between individual differences in working memory capacity and mind-wandering using thought probes on the SART. The results indicate that SART performance does not differ whether thought probes are included or not. Individuals higher in working memory capacity produced better SART performance in the conditions with and without thought probes. In addition, individuals in working memory capacity were negatively correlated with mind-wandering frequency. The results indicate that thought probe measurement is a non-reactive method to measure mind-wandering in attention and inhibition tasks.

The Influence of Individual Differences in Cognitive Ability on Working Memory Training Gains.

Working memory training research has produced mixed results in terms of finding benefits beyond the trained tasks (i.e., transfer). One potential limitation is that the research thus far has failed to isolate the specific combination of factors that makes working memory training work best. Individual differences in cognitive ability at pretest may be an important factor, suggesting possible aptitude-by-treatment interactions. Baseline cognitive ability could be (a) positively related, (b) negatively related, or (c) unrelated to training task improvements. The relationship between ability and training gains is important given the idea that larger training improvements should lead to greater transfer. However, the majority of training studies tend to be under-powered to examine individual differences. We pooled studies conducted in related labs to increase power while minimizing differences between studies. In the studies that were identified for this project, young adults completed complex span training and working memory and/or fluid intelligence as pretest measures. The combined samples from seven studies resulted in a sample of 192 participants. Analyses focused on the relationship between pretest cognitive ability and training performance across training days. There was no evidence that individuals lower in cognitive ability improved more than high-ability subjects on the training tasks. Instead, we found a positive relationship for both working memory and fluid intelligence measured at pretest with the amount of training improvement. In addition, the association between pretest working memory and working memory training performance appears to be domain-general - verbal and visuospatial content do not produce differential relationships.

Working memory capacity and intra-individual variability of proactive control.

Two datasets of 110 young adults were examined to investigate the relationship between individual differences in working memory capacity (WMC) and dynamic cognitive control. The results delve into the specific differences between high- and low-WMC individuals' ability to enact and maintain cognitive control using the AX version of the continuous performance test (AX-CPT). Compared to high-WMC individuals, low-WMC individuals: (a) made more errors, specifically to AX targets; (b) exhibited a partial shift to proactive control with more time-on-task; (c) had more exaggerated slower AX target responses in the tail of the response time distribution; and (d) were equally likely to adjust control after conflict. These results fit with the dual mechanisms of cognitive control theory and goal-maintenance account, and further clarify how individual differences in WMC manifests as intra-individual variability in cognitive control.

Do the effects of working memory training depend on baseline ability level?

There is a debate about the ability to improve cognitive abilities such as fluid intelligence through training on tasks of working memory capacity. The question addressed in the research presented here is who benefits the most from training: people with low cognitive ability or people with high cognitive ability? Subjects with high and low working memory capacity completed a 23-session study that included 3 assessment sessions, and 20 sessions of training on 1 of 3 training regiments: complex span training, running span training, or an active-control task. Consistent with other research, the authors found that training on 1 executive function did not transfer to ability on a different cognitive ability. High working memory subjects showed the largest gains on the training tasks themselves relative to the low working memory subjects-a finding that suggests high spans benefit more than low spans from training with executive function tasks. (PsycINFO Database Record

Working Memory Training Does Not Improve Performance on Measures of Intelligence or Other Measures of "Far Transfer": Evidence From a Meta-Analytic Review.

It has been claimed that working memory training programs produce diverse beneficial effects. This article presents a meta-analysis of working memory training studies (with a pretest-posttest design and a control group) that have examined transfer to other measures (nonverbal ability, verbal ability, word decoding, reading comprehension, or arithmetic; 87 publications with 145 experimental comparisons). Immediately following training there were reliable improvements on measures of intermediate transfer (verbal and visuospatial working memory). For measures of far transfer (nonverbal ability, verbal ability, word decoding, reading comprehension, arithmetic) there was no convincing evidence of any reliable improvements when working memory training was compared with a treated control condition. Furthermore, mediation analyses indicated that across studies, the degree of improvement on working memory measures was not related to the magnitude of far-transfer effects found. Finally, analysis of publication bias shows that there is no evidential value from the studies of working memory training using treated controls. The authors conclude that working memory training programs appear to produce short-term, specific training effects that do not generalize to measures of "real-world" cognitive skills. These results seriously question the practical and theoretical importance of current computerized working memory programs as methods of training working memory skills.