An item response theory approach to the measurement of working memory capacity.

Complex span tasks are perhaps the most widely used paradigm to measure working memory capacity (WMC). Researchers assume that all types of complex span tasks assess domain-general WM. However, most research supporting this claim comes from factor analysis approaches that do not examine task performance at the item level, thus not allowing comparison of the characteristics of verbal and spatial complex span tasks. Item response theory (IRT) can help determine the extent to which different complex span tasks assess domain-general WM. In the current study, spatial and verbal complex span tasks were examined using IRT. The results revealed differences between verbal and spatial tasks in terms of item difficulty and block difficulty, and showed that most subjects with below-average ability were able to answer most items correctly across all tasks. In line with previous research, the findings suggest that examining domain-general WM by using only one task might elicit skewed scores based on task domain. Further, visuospatial complex span tasks should be prioritized as a measure of WMC if resources are limited.

Testing the Effectiveness of Computerized Cognitive Training on an At-Risk Student Population.

Core constructs such as working memory, task switching, and processing speed in cognitive psychology research have prominent predictive roles in K12 students' academic performance. Specifically, considerable empirical work shows that variability in such capabilities is linked to differences in numerous academic outcomes. Moreover, there is an increasing awareness and acceptance of the malleability of cognitive abilities. Thus, an emerging strand of research focuses on the use of computerized cognitive training to improve cognitive skills. This project addresses this issue with high-risk students attending community day schools. An in-school cognitive training program implemented (for 30 min per day) at each school site resulted in improvements for working memory, task switching, and processing speed after six total hours of participation. The current results provide evidence for the changeability of what were once thought to be static skills. Equally important, this study highlights the effectiveness of computerized cognitive training and critically extends intervention-based work to a student group that has received little attention. Implications of this work for cognitive research and educational support programs are discussed.

Improving Cognitive Abilities in School-Age Children via Computerized Cognitive Training: Examining the Effect of Extended Training Duration.

Critical neuropsychological capabilities such as working memory, cognitive flexibility, and processing speed are foundational to many daily activities. For children, such skills are essential for school success. Thus, children who demonstrate weaknesses in these abilities may experience impaired academic performance; this is especially true for students identified with learning differences who often exhibit less developed cognitive abilities. The purpose of this project was to examine the efficacy of a cognitive training program implemented during the school day to improve abilities predictive of academic achievement. Ninety-five children completed two training activities that were counterbalanced across participants. Analyses of baseline working memory, cognitive flexibility, and processing speed performance relative to those following training showed a strong treatment effect. Moreover, there is notable evidence of greater intervention efficacy with extended engagement with the training program. Implications for neuropsychological research and practice are discussed.

The Psychometric Structure of Executive Functions: A Satisfactory Measurement Model? An Examination Using Meta-Analysis and Network Modeling.

A long-standing debate among cognitive scientists has focused on describing the underlying nature of executive functions, which has important implications for both theoretical and applied research. Miyake et al.'s three-factor model has often been considered the gold-standard representation of executive functions and has driven much research in the field. More recently, however, there have been increasing concerns that the three-factor model does not adequately describe a highly complex construct such as executive functions. The current project presents two studies that examine the veracity of Miyake et al.'s model and propose a new approach (i.e., network modeling) for detecting the underlying nature of executive functions. The current results raise questions about the psychometric strength and adequacy of the three-factor model. Further, the studies presented here provide evidence that network modeling provides a better understanding of executive functions as it better captures (relative to latent variable modeling) the complexity of cognitive processes. Theoretical and applied implications are discussed.

Working memory capacity and dual mechanisms of cognitive control: An experimental-correlational approach.

Working memory is thought to be strongly related to cognitive control. Recent studies have sought to understand this relationship under the prism of the dual mechanisms of control (DMC) framework, in which cognitive control is thought to operate in two distinct modes: proactive and reactive. Several authors have concluded that a high working memory capacity is associated with a tendency to engage the more effective mechanism of proactive control. However, the predicted pattern of proactive control use has never been observed; correlational evidence is made difficult to interpret by the overall superiority of participants with a high working memory capacity: they tend to perform better even when proactive control should be detrimental. In two experiments, we used an experimental-correlational approach to experimentally induce the use of reactive or proactive control in the AX-CPT. The relation between working memory capacity and performance was unaffected, incompatible with the hypothesis that the better performance of participants with a high working memory capacity in the task is due to their use of proactive control. It remains unclear how individual differences in working memory capacity relate to cognitive control under the DMC framework.

Utilizing Cognitive Training to Improve Working Memory, Attention, and Impulsivity in School-Aged Children with ADHD and SLD.

Students' use of working memory (WM) is a key to academic success, as many subject areas and various tasks school-aged children encounter require the ability to attend to, work with, and recall information. Children with poor WM ability typically struggle with academic work compared to similar-aged peers without WM deficits. Further, WM has been shown to be significantly correlated with inattention and disorganization in those with ADHD, and WM deficits have also been identified as a potential underpinning of specific learning disorder (SLD). As an intervention technique, the use of computerized cognitive training has demonstrated improved attention and working memory skills in children with WM deficits, and children that have completed cognitive training protocols have demonstrated performance improvements in reading and math. The current study aimed to examine the effectiveness of cognitive training (conducted in a clinical setting) for students diagnosed with ADHD and SLD. Using paired-samples t-tests and a psychometric network modeling technique, results from data obtained from a sample of 43 school-aged children showed (1) that attention and working memory improved following cognitive training and (2) that cognitive training might be related to cognitive structural changes found pre- to post-training among the variables being measured. Implications for clinical practice and school-based interventions are discussed.

Individual Differences in Attention and Intelligence: A United Cognitive/Psychometric Approach.

Process overlap theory (POT) is a new theoretical framework designed to account for the general factor of intelligence (g). According to POT, g does not reflect a general cognitive ability. Instead, g is the result of multiple domain-general executive attention processes and multiple domain-specific processes that are sampled in an overlapping manner across a battery of intelligence tests. POT explains several benchmark findings on human intelligence. However, the precise nature of the executive attention processes underlying g remains unclear. In the current paper, we discuss challenges associated with building a theory of individual differences in attention and intelligence. We argue that the conflation of psychological theories and statistical models, as well as problematic inferences based on latent variables, impedes research progress and prevents theory building. Two studies designed to illustrate the unique features of POT relative to previous approaches are presented. In Study 1, a simulation is presented to illustrate precisely how POT accounts for the relationship between executive attention processes and g. In Study 2, three datasets from previous studies are reanalyzed (N = 243, N = 234, N = 945) and reveal a discrepancy between the POT simulated model and the unity/diversity model of executive function. We suggest that this discrepancy is largely due to methodological problems in previous studies but also reflects different goals of research on individual differences in attention. The unity/diversity model is designed to facilitate research on executive function and dysfunction associated with cognitive and neural development and disease. POT is uniquely suited to guide and facilitate research on individual differences in cognitive ability and the investigation of executive attention processes underlying g.