Publisher Summary This chapter focuses on the modern notion of short-term memory, called working memory. Working memory refers to the temporary maintenance of information that was just experienced or just retrieved from long-term memory but no longer exists in the external environment. These internal representations are short-lived, but can be maintained for longer periods of time through active rehearsal strategies, and can be subjected to various operations that manipulate the information in such a way that makes it useful for goal-directed behavior. Working memory is a system that is critically important in cognition and seems necessary in the course of performing many other cognitive functions, such as reasoning, language comprehension, planning, and spatial processing. This chapter demonstrates the functional importance of dopamine to working memory function in several ways. Elucidation of the cognitive and neural mechanisms underlying human working memory is an important focus of cognitive neuroscience and neurology for much of the past decade. One conclusion that arises from research is that working memory, a faculty that enables temporary storage and manipulation of information in the service of behavioral goals, can be viewed as neither a unitary, nor a dedicated system. Data from numerous neuropsychological and neurophysiological studies in animals and humans demonstrates that a network of brain regions, including the prefrontal cortex, is critical for the active maintenance of internal representations.

Chapter 11 Working memory

because observed behavior is the result of interactions between environmental factors and genes during the extended period of development. Therefore, to better understand expert and exceptional performance, we must require that the account specify the different environmental factors that could selectively promote and facilitate the achievement of such performance. In addition, recent research on expert performance and expertise (Chi, Glaser, & Farr, 1988; Ericsson & Smith, 1991a) has shown that important characteristics of experts' superior performance are acquired through experience and that the effect of practice on performance is larger than earlier believed possible. For this reason, an account of exceptional performance must specify the environmental circumstances, such as the duration and structure of activities, and necessary minimal biological attributes that lead to the acquisition of such characteristics and a corresponding level of performance. An account that explains how a majority of individuals can attain a given level of expert performance might seem inherently unable to explain the exceptional performance of only a small number of individuals. However, if such an empirical account could be empirically supported, then the extreme characteristics of experts could be viewed as having been acquired through learning and adaptation, and studies of expert performance could provide unique insights into the possibilities and limits of change in cognitive capacities and bodily functions. In this article we propose a theoretical framework that explains expert performance in terms of acquired characteristics resulting from extended deliberate practice and that limits the role of innate (inherited) characteristics to general levels of activity and emotionality. We provide empirical support from two new studies and from already published evidence on expert performance in many different domains.

/pdf/the-role-of-deliberate-practice-in-the-acquisition-of-expert-3j9768t5su.pdf

The role of deliberate practice in the acquisition of expert performance.

I have developed "tennis elbow" from lugging this book around the past four weeks, but it is worth the pain, the effort, and the aspirin. It is also worth the (relatively speaking) bargain price. Including appendixes, this book contains 894 pages of text. The entire panorama of the neural sciences is surveyed and examined, and it is comprehensive in its scope, from genomes to social behaviors. The editors explicitly state that the book is designed as "an introductory text for students of biology, behavior, and medicine," but it is hard to imagine any audience, interested in any fragment of neuroscience at any level of sophistication, that would not enjoy this book. The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or

Principles of Neural Science

A theory is proposed to account for some of the age-related differences reported in measures of Type A or fluid cognition. The central hypothesis in the theory is that increased age in adulthood is associated with a decrease in the speed with which many processing operations can be executed and that this reduction in speed leads to impairments in cognitive functioning because of what are termed the limited time mechanism and the simultaneity mechanism. That is, cognitive performance is degraded when processing is slow because relevant operations cannot be successfully executed (limited time) and because the products of early processing may no longer be available when later processing is complete (simultaneity). Several types of evidence, such as the discovery of considerable shared age-related variance across various measures of speed and large attenuation of the age-related influences on cognitive measures after statistical control of measures of speed, are consistent with this theory.

http://www.anitacrawley.net/Resources/Articles/salthouse%20The%20Processing%20Speed%20Theory%20of%20Adult%20Age%20Differences%20in%20Cognition.pdf

The processing-speed theory of adult age differences in cognition.

http://psych.colorado.edu/~kimlab/Botvinick.etal.TICS.2004.pdf

Conflict monitoring and anterior cingulate cortex: an update

Old adults' (N = 24) and young adults' (N = 24) speed of producing exemplars of semantic categories (i.e., semantic fluency) varying in difficulty was assessed both in a standard condition and in a "set-switching" condition where exemplars had to be produced from 2 categories in an alternating manner. "Retrieval-position function" parameters were used to assess speed of semantic access independent of nonsemantic factors. Results suggested age effects in nonsemantic components but not in semantic retrieval per se. Also, age deficits in set switching were relatively subtle. Findings are discussed with relation to issues of domain specificity of age effects as well as of the role of executive control during semantic retrieval and age differences therein.

Complex semantic processing in old age: does it stay or does it go?

The voluntary task-switching paradigm requires subjects to select randomly between tasks and promises to provide a window into executive task selection independent of exogenous influences present in standard task-switching situations. We show here that the degree to which subjects perseverate on tasks across trials captures unique individual differences variance, but also that the switch rate is under strong stimulus-driven control: “Voluntary” switches are much more frequent when the stimulus changes than when it repeats. Most important, we show that individuals whose no-switch trials are selectively slowed exhibit less perseveration and stimulus-driven effects (and thus more voluntary selection) than individuals whose no-switch trials do not show this slowing. We suggest that selective slowing indicates a strategy of treating trials as discrete events—possibly through inhibition of the preceding task set. These results not only demonstrate massive nonvoluntary influences on voluntary selection that are ...

On How to Be Unpredictable Evidence From the Voluntary Task-Switching Paradigm

Recent findings suggesting that switch costs in the task-cuing paradigm are largely attributable to a change in the task-indicating cue have been interpreted in terms of a priming model of task-switch costs (Logan & Bundesen, 2003). According to this explanation, participants do not actually switch task sets, but merely use a cue-stimulus compound to disambiguate competing response tendencies associated with bivalent stimuli. Here, we report an event-related potential (ERP) experiment that provides evidence against this notion. In a paradigm with a 2:1 mapping between cues and tasks, we show that cue-switch and task-switch effects are dissociable on a neurophysiological level, indicating that task switching is more than a switch in the task-indicating cue. Moreover, a systematic analysis of the ERPs during the cue-stimulus interval suggests that updating processes can run in advance, before the stimulus is presented.

/pdf/is-task-switching-nothing-but-cue-priming-evidence-from-erps-3akzsghif6.pdf

Is Task Switching Nothing but Cue Priming? Evidence from ERPs

http://library.mpib-berlin.mpg.de/ft/ul/UL_Cognitive_2014.pdf

Cognitive aging: is there a dark side to environmental support?

The cognitive neuroscience revolution rests on two cornerstones: simple experimental paradigms to capture critical components of the mind and new methods to watch what the brain is doing while working in these paradigms. Michael I. Posner has been a driving force behind the use of componential and functionaly analysis to enhance our knowledge of mindbrain relationships. His schoarship has been pivotal in opening up new theoretical and methodological trajectories in the field.

Ulrich Mayr

Papers

Complex semantic processing in old age: does it stay or does it go?

On How to Be Unpredictable Evidence From the Voluntary Task-Switching Paradigm

Is Task Switching Nothing but Cue Priming? Evidence from ERPs

Cognitive aging: is there a dark side to environmental support?

Developing individuality in the human brain : a tribute to Michael I. Posner