Bayliss et al. (2003) investigate the working memory capacity in two experiments, one with children ages 3-4 and another with college undergraduates. The results of both studies indicate that the storage capacity of the phonological loop and the visual-spatial sketchpad impact the results of complex span tasks. Another discovery of this investigation determines that the speed of an individual’s processing ability impacts performance on complex span tasks as well. Bayliss et al. (2003) concluded that the phonological loop and visual-spatial sketchpad store information separately from how they process information. Both the storing and the processing of information are supported by the central executive function. The phonological loop and the visual-spatial sketchpad are thus domain specific, in that they store pieces of information as independent functions. In order to process the information stored, however, the phonological loop and the visual-spatial sketchpad rely on the central executive, a domain general resource. Therefore, the processing and storing of information does not compete for space from the same resource.
The study of the fractionation of working memory by Tsujimoto, Kuwajima, and Sawaguchi (2007) helps to explain this domain specific and domain general discourse. According to the study, the lateral areas of the prefrontal cortex (LPFC) undergo an intense maturation process between the years 2-7. The density of the neurons lessens, dendrite trees expand, and gray and white matter increases. Studies done on adults show this fractionation of the brain when during visual and auditory working memory tasks, separate regions of the brain are activated. Meanwhile, other studies show that children's brains are not fractionated before age 4. More specifically, visuospatial fractionation seems to begin closer to ages 8-9. Further fractionation of the working memory into two domain specific functions, the phonological loop and the visuospatial sketchpad, occurs throughout adolescence and enhances the cognitive abilities of children. The rate at which individual’s brains achieve fractionation varies. As domain specific functions, the PL and the VS have a greater capacity for encoding, processing, and storing. Also, the domain general central executive begins to aid in strategy selection, discipline, and discretionary actions.
Within their article, Tsujimoto, Kuwajima, and Sawaguchi (2007) cite other studies that suggest that the fractionation of the working memory does not take place until after 4 years old. As a result of their study, Tsujimoto, Kuwajima, and Sawaguchi (2007) found that visuospatial and auditory working memory and response inhibition functions are related to each other in children ages 5-6. On the other hand, in children ages 8-9, these functions are independent. The fractionating of neural systems for working memory in older children allows them to become more efficient when processing critical cognitive functions. Now that older children have developed the central executive function, they may use a wider variety of cognitive strategies that affect behavior as well as learning.
Andersson and Lyxell (2007) cite studies by Alloway and colleagues (in press) as well as Gathercole et al., (2004a) and Gatehercole et al., (2004b) that support the above findings. These references connect the last two ideas, domain specific and domain general with fractionation. The multi-component model of the working memory is concluded to contain domain-specific components for storage and a domain-general control component for processing. The findings indicate that this multi-component model is present as early as 4 years old in some individuals.
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3 comments:
"The study of the fractionation of working memory by Tsujimoto, Kuwajima, and Sawaguchi (2007)"
Explain first how the authors define fractionation (since it is a physiological process but which has influence on the memory). Then link it to domain specificity topic./.
Good improvement.
The idea of fractionation is really interesting! I'm really fascinated by how the brain develops in the early years, because my family and I often discuss the effects of an enriched environment on brain development (and also the reverse, i.e. the brain perhaps develops less when not stimulated or enriched). I'm supposing that enriched external stimulus would increase fractionation or maybe the depth of fractionation. I think this idea really explains what Piaget describes in his stages of development and reasoning. Interesting review!
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