Working Memory Training and Transcranial Direct Current Stimulation

The aim of this chapter is to contribute to the discussion of the cognitive neuroscience of brain stimulation. In doing so, the authors emphasize work from their own laboratory that focuses both on working memory training and transcranial direct current stimulation. Transcranial direct current stimulation is one of the most commonly used and extensively researched methods of transcranial electrical stimulation. The chapter focuses on implementation of transcranial direct current stimulation to enhance and inform research on working memory training, and not on the underlying mechanisms of transcranial direct current stimulation. Thus, while respecting the intricacies and unknowns of the inner workings of electrical stimulation on the brain, the chapter relies on the premise that transcranial direct current stimulation is able to directly affect the electrophysiological profile of the brain and provides evidence that this in turn can influence behavior given the right parameters.

How Strong Is the Evidence for the Effectiveness of Working Memory Training?

This chapter argues that the question of whether working memory training can induce cognitive plasticity in terms of transfer effects cannot be conclusively answered yet due to persisting methodological issues across the literature. The shortcomings discussed include the lack of theoretically motivated selection of training and transfer tasks, the lack of active control groups, and small sample sizes. These problems call into question the strength of the existing evidence. Indeed, reevaluating published findings with Bayesian inference indicated that only a subset of published studies contributed interpretable evidence. The chapter concludes that the current body of literature cannot conclusively support claims that WM training does or does not improve cognitive abilities and stresses the need for theory-driven, methodologically sound studies with larger sample sizes.

Neuroscience Perspectives on Cognitive Training

The aim of this chapter is to spark a discussion regarding how cognitive neuroscience research can aid in the evaluation and development of effective cognitive training protocols. In particular, the authors pose questions relating to whether training-related neural plasticity (i.e., changes in brain function and structure in response to experience) could be used to facilitate the identification and targeting of the neural systems (for working memory and other executive functions) that both support performance on a desired outcome task (e.g., speech recognition) and are alterable via training. The chapter describes approaches that provide unique methodological perspectives for understanding the neural systems that support training-related improvements in cognition. The chapter also highlights the multiple challenges that have emerged from behavioral studies of cognitive training and that neuroscience techniques may help to address, including: establishing the extent to which cognitive training benefits exist for trained tasks and materials, transfer to untrained tasks and materials, persist for extended periods of time, and are effective across a range of individuals. Cognitive neuroscience research has begun not only to tackle these challenges but also to pose new questions, such as: Can training benefits be maximized via regulating or stimulating the neural systems that support behavior? How might our current approaches to cognitive training be significantly altered by novel and developing cognitive neuroscience methodologies?

Working Memory Training From an Individual Differences Perspective

This chapter presents and discusses a verbal WM training developed for older adults. The model of working memory (WM) proposed by Cornoldi and Vecchi, which is based on an analysis of individual and age-related differences, is used as a framework for discussing the efficacy of the WM training procedure proposed and developed for older adults. The model (a) assumes that different WM tasks (and underlying processes) may be located along two continua that describe the type of content to be processed and the degree of active control required by the task and (b) considers metacognitive/motivational aspects, which also have a role in determining WM performance. The WM training procedure presented here takes into account not only the capacity to use WM resources and attentional control by adopting an adaptive procedure, but also the importance of including variations in the training task demands to produce a challenging and engaging task that sustains motivation and favor the training’s short- and long-term efficacy, at least in older adults. These aspects seem crucial in explaining the results obtained with this verbal WM training program in aging.

Epilogue

This volume aims to summarize the state of the art in the working memory (WM) training literature. The idea for the book was conceived in 2011 and at the time the notion that general cognitive abilities could be improved through training was exciting yet controversial. The early evidence, although imperfect, was tantalizing: Several studies had seemingly illustrated that people’s performance on untrained measures of intellectual abilities could be improved after just a few hours of training on cognitively demanding tasks (...

Fundamental Questions Surrounding Efforts to Improve Cognitive Function Through Video Game Training

Neural plasticity, or the ability of the brain to reorganize its structure and activity, is of critical importance. For nearly 50 years, the dominant framework in the field of learning and neural plasticity held that the brain was capable of truly large-scale changes only early in life. However, emerging evidence suggests that plasticity that had assumed to be “lost” due to age, injury, or disease may be at least partially re-established via genetic, pharmacological, and/or behavioral means. Yet, while it is true that humans retain a significant capacity to learn throughout the life span, a second roadblock frequently stands in the way of translating learning gains into practical real-world benefits. This obstacle is the “curse of specificity.” While it is true that, given appropriate training, humans will tend to improve on almost any task, the improvements that are observed are often confined to the exact training task, with little to no benefits of the training being observed for even seemingly very similar tasks. This chapter discusses the trend toward task-specific training on one working memory task, as well as the finding that action video game training does appear to lead to more generalizable improvements in cognitive performance.

The Effectiveness of Training in Task Switching

The authors of this chapter describe changes in task-switching abilities over the life span. In particular, task maintenance and selection processes decline in older age. The authors summarize conditions under which the flexibility and plasticity of these processes can be improved such as external and internal prompts to behavior and intensive practice. The effectiveness of task-switching training interventions is evaluated by highlighting conditions under which transfer effects to other cognitive abilities are more likely to occur such as training variability. The author also discuss the usefulness of strategy-based interventions, the impact of inter-individual differences in baseline performance, and the specific role of motivation on the success of training in task switching.

Music Training

This chapter focuses on the possibility that music training could serve as a type of cognitive training. Music is an interesting potential avenue for cognitive training not only because music learning and processing are likely to draw heavily on executive function abilities, but also because musical experience has its own intrinsic rewards. This suggests that music training might serve as a particularly enjoyable and rewarding route to cognitive training. The authors describe some theoretical reasons to expect a strong relationship between executive function and music, describe the small body of work that has experimentally assessed the possibility that musical experience might transfer to executive function abilities, and finally recommend ways in which a music training program might strengthen cognitive abilities.

Cognitive Perspectives of Working Memory Training

Working memory training is an emergent field aimed at improving general cognitive abilities through targeted brain exercises. The prospect of improving cognitive abilities, such as attention control, comprehension, and reasoning, has piqued the interest of the scientific community and the general public alike. If cognitive abilities like working memory capacity can be improved, it is assumed that this improvement will result in benefits to a broad range of real-world abilities associated with working memory capacity, including reading comprehension, math performance, and attention control. Thus, the goal of working memory training is to demonstrate broad transfer to tasks that involve the same components of working memory that were targeted during training. Therefore, improvements should be observed on a broad range of tasks that tap the ability being trained. This is measured by observing the difference between pre- and posttest performance on cognitive tasks that subjects have not practiced. The aim of this chapter is to summarize the extant literature on working memory training and then to pose a series of questions to researchers investigating the efficacy of working memory training.

Logical and Methodological Considerations in Cognitive Training Research

It is unclear whether existing computer-based cognitive training can improve prefrontal function in a manner relevant to real-life outcomes. An important scientific goal for research is to identify the necessary and sufficient experiences that could lead to the creation of efficient and effective cognitive interventions. Researchers who have developed computerized cognitive training interventions have attempted to identify the core executive processes of the prefrontal cortex and to target and tax exactly those processes. However, a vast space of possibilities (and potential barriers) remains between the development of targeted and successful cognitive interventions and the natural set of rich early-life experiences that have been shown to be important in the development of prefrontal function. To construct efficient, effective training interventions that may generalize to real-life outcomes, properly mapping out this space is necessary. Therefore, the chapter discusses the cognitive skills that are the focus of many cognitive interventions: executive functions, working memory, and functions of the prefrontal cortex.