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Many learners in South Africa first encounter English when it is used as a medium of instruction at the start of formal schooling. This has ramifications for literacy acquisition and academic performance. Working memory is responsible for distributing cognitive resources among the various processing and storage tasks. It has been pivotal in many cognitive theories linking working memory to academic skills like reading comprehension and mathematics ability. In addition, research indicates that both Short Term Memory (STM) and Working Memory (WM) are instrumental in cognitive processing but that in bilinguals their roles are more complex than they are in monolinguals. This research explored the capacity of WM and the role of WM in reading comprehension and mathematical ability in two South African populations: a monolingual English group (L1) and a bilingual Afrikaans/English group (L2). No significant differences were found in the WM capacity of the two groups. In the second part of the study it was found that both reading comprehension and bilingualism depend on the same verbal domain resources of WM, which act as constraining factors for the L2 group. However, in the L1 group, there appeared to be less competition for verbal domain resources and more for visuospatial resources probably due to the phase of literacy acquisition these learners were in. In terms of WM and mathematical ability it was found that bilinguals exceed their storage capacity (STM) before they run out of processing capacity (WM). STM therefore is a constraining factor for this group. However, for the L1 group, visuospatial processing is the constraining factor. The research concludes that bilinguals use WM both for semantic processing of their nondominant language and for complex cognitive processing. While the WM capacity for monolingual and bilingual learners appears to be equivalent, the way the resources are allocated during cognitive tasks differ.

Working memory, which enables the temporary storage of information in an active “online” state, is an exceptionally capacity limited system. Given this capacity limit, irrelevant information in our environment must be filtered out, while relevant representation is maintained. Research has shown that neural oscillations in the alpha frequency range (8-12Hz) are greatly influenced by the number of items in memory. Most work has argued that alpha oscillations primarily support working memory processing by suppressing information that could interfere with items already in memory, as indexed by an increase in alpha power. However, other work has shown that decreases in alpha power, with little evidence of concurrent increases, support the maintenance of working memory representations. In this thesis we show that, in the context of visual working memory, the primary role of alpha oscillations is to maintain distinct working memory representations, rather than to suppress irrelevant information. This is shown in a series of three experiments all indicating that as the number of relevant items increases, the power of alpha oscillations systematically decreases. In the first experiment, we use a whole report and change detection task to examine how the number of items in memory influences alpha oscillations. In the second experiment, we use a cuing (Experiment 2A) and filtering (Experiment 2B) paradigm to demonstrate that alpha power tracks the number of remembered items instead of the number of total items on the screen. Lastly, by presenting items sequentially (Experiment 3A) or in overlapping locations (Experiment 3B), we see evidence that decreases in alpha power are related to the maintenance of relevant spatial locations, instead of the number of items in memory. The results of the experiments suggest that alpha power reflects the maintenance of relevant working memory representations, rather than the suppression of irrelevant external distractors or the inhibition of task-irrelevant neural areas. Furthermore, our last experiment indicates that the alpha frequency band is especially sensitive to the maintenance of spatial information.

During scene viewing, visual working memory (VWM) is used to retain information from recently attended and fixated objects. In the present study, I examined whether and how people can strategically control the content of VWM during scene viewing, prioritizing task-relevant objects for retention even as the eyes are directed to subsequent objects. Participants viewed a set of real-world objects presented serially within a 3-D rendered scene. One object in the sequence was cued by a tone as to-be-remembered. At the end of the sequence, memory for the visual form of one object was tested. Participants exhibited tight control over the content of VWM, implementing prioritization after the encoding of an object into VWM, protecting that item from subsequent interference. Participants also successfully reallocated protection to subsequent objects, regardless of the duration of prioritization of the original item. Such strategic maintenance of objects in VWM is likely to play an important role in real-world visual behavior, especially when object information must be maintained across shifts of attention and the eyes to other objects (such as when comparing two spatially separated objects).

Evidence is presented that supports the view that most models of short-term memory cannot account for the flexibility of the primary memory system. It is argued that the working memory model outlined by Baddeley and Hitch (1974) is, however, a potentially adequate model. Working memory, in this thesis, is depicted as a system that assembles 'constellations' consisting of the central executive and one or more sub-systems. This view suggests a formulation that is considerably more complex than the 1974 model. The empirical studies examine the role of the visuo-spatial scratch pad in the formation and maintenance of working memory constellations. It is concluded from these studies that the scratch pad is independent of the articulatory loop but is usually coupled to the central executive except during maintenance rehearsal. Furthermore, it can be used concurrently with the articulatory loop to process spatial aspects of highly verbal tasks. However a constellation consisting of the executive, the loop and the scratch pad is vulnerable to a wider range of interference effects than a simpler constellation. Paivio (1971) suggested that 'dual coding' leads to better memory performance, however, this is only the case when no distractors are present. The final two chapters present some speculations on how working memory research might proceed in the future. It is concluded that the current trend towards collecting convergent evidence and the emphasis on testing theory in applied situations should give us insights into memory that were not available to Ebbinghaus and other early memory researchers.

One of the best ways to increase memory performance on a task is to organize the to-be-remembered material (Postman, 1972). Throughout a number of experiments, the amount a subject organizes a list of words has been shown to be related to their overall recall performance (e.g., Mandler & Pearlstone, 1966). However, few studies have investigated whether other cognitive abilities are related to the organization of memory and whether these other abilities contribute to the relationship between organization and memory performance. In the present study subjects completed four sets of multitrial free recall and the consistency in which subjects recalled words (a measure of organization) was compared to performance on multiple measures of working memory capacity and fluid intelligence. I show that working memory capacity is related to the organization of memory particularly when subjects were told to use an organizational strategy and that fluid intelligence is related to organization regardless of strategy. Additionally, both working memory capacity and organization predict unique variance in immediate free recall performance.

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This study examines how undergraduate students use hand gestures to offload cognitive demands on their working memory (WM) when they are engaged in three major proving activities: reading, presenting, and constructing proofs of mathematical conjectures. Existing research literature on the role of gesturing in cognitive offloading has been limited to the context of elementary mathematics but has shown promise for extension to the college level. My framework weaves together theoretical constructs from mathematics education and cognitive psychology: gestures, WM, and mathematical proofs. Piagetian and embodied perspectives allow for the integration of these constructs through positioning bodily activity at the core of human cognition. This framework is operationalized through the methodology for measuring cognitive demands of proofs, which is used to identify the set of mental schemes that are activated simultaneously, as well as the places of potential cognitive overload. The data examined in this dissertation includes individual clinical interviews with six undergraduate students enrolled in different sections of the Introduction to Proofs course in Fall 2021 and Spring 2022. Each student participated in seven interviews: two WM assessments, three proofs-based interviews, a stimulated recall interview (SRI), and post-interview assessments. In total, 42 interviews were conducted. The participants' hand gesturing and mathematical reasoning were qualitatively analyzed. Ultimately, students' reflections during SRIs helped me triangulate the initial data findings. The findings suggest that, in absence of other forms of offloading, hand gesturing may become a convenient, powerful, although not an exclusive offloading mechanism: several participants employed alternative mental strategies in overcoming the cognitive overload they experienced. To better understand what constitutes the essence of cognitive offloading via hand gesturing, I propose a typology of offloading gestures. This typology differs from the existing classification schemes by capturing the cognitive nuances of hand gestures rather than reflecting their mechanical characteristics or the underlying mathematical content. Employing the emerged typology, I then show that cognitive offloading takes different forms when students read or construct proofs, and when they present proofs to the interviewer. Finally, I report on some WM-related issues in presenting and constructing proofs that can be attributed to the potential side effects of mathematical chunking. The dissertation concludes with a discussion of the limitations and practical implications of this project, as well as foreshadowing the avenues for future research. / Doctor of Philosophy / In this study, I examined how undergraduate students can rely on their hand gesturing to reduce the cognitive complexity of mathematical proofs. Specifically, I studied gestures produced by students when they are engaged in various kinds of proving activities: reading for comprehension, reading for validation, presenting, and constructing proofs of mathematical conjectures. During the experiments, the participants were not given pencils/paper, calculators, or any other and other figurative materials. Therefore, they had to rely on their imagination, working memory, and hand gestures to make progress on the tasks. Results suggest that students' hand gestures have a beneficial effect in navigating cognitive challenges associated with mathematical proofs. Moreover, I show that this effect takes different forms depending on the proving activity in which the student engages. Finally, I report on some memory-related issues in presenting and constructing proofs. The dissertation concludes with a discussion of the limitations and practical implications of this project, as well as foreshadowing the avenues for future research.

The literature suggests working memory can have a significant effect on children's academic success. A number of working memory training programmes have been developed as tools for helping children to boost their working memory and learning ability. The reliability and validity of this body of evidence has been challenged recently with questions raised as to whether such programmes actually do boost working memory or show any subsequent impact upon learning. The thesis contains an evaluative systematic review examining eight studies from the last decade that explore the effects of working memory training on working memory, literacy and numeracy. The review found significant near and far transfer effects for improvements to working memory with differences in the pattern of these improvements. The assertion that working memory training leads to improvements in other areas such as literacy and numeracy is also challenged. The thesis also contains an examination of the efficacy of a paired whole class working memory intervention in delivering improvements in the working memory, literacy and numeracy skills of primary aged school children. The pre-experimental design tested the impact of the intervention on the working memory, literacy and numeracy of a sample of forty-one Year 4 children. The data demonstrated a significant positive immediate effect of the programme on verbal working memory recall and processing and visual-spatial working memory processing and recall. No significant immediate effects of the programme were found on numeracy or literacy. Finally a critical appraisal of concepts of evidence based practice and a review of the literature regarding the dissemination of research and notions of research impact is presented. The implications of the current research for professional practice is explored in terms of the care that must be taken by educational professionals in offering up working memory training programmes as solutions to academic underachievement in children.

The current study explored the relationship between working memory (WM) and reading performance in 50 typically-developing third-grade students, as well as the effect of WM-training on their WM, reading fluency, and reading comprehension skills. Half of the sample was randomly assigned to the experimental group, while the other half was placed in the control group. Children in both groups participated in a battery of WM and reading assessments preceding and following three weeks of computer game play. The children in the experimental group played a WM-training computer game for about 10 minutes a day (Monday-Friday) for three weeks, while children in the control group played a computer game that required sustained attention, but did not have a WM component. It was hypothesized that WM performance would predict reading performance, such that better WM ability would be associated with better reading ability. Furthermore, it was predicted that WM span would mediate the relationship between reading fluency and reading comprehension. In terms of WM training, it was hypothesized that WM training would significantly improve the experimental group's performance on the measures of WM, reading fluency, and reading comprehension relative to the control group. Results indicated that WM ability significantly predicted performance on measures of reading fluency and reading comprehension at pre-test; however, WM performance was not observed to mediate the relationship between reading fluency and reading comprehension despite being closely associated with both skills. Finally, although children in the experimental group did not show improvements in WM performance relative to those in the control group on transfer tasks, they did demonstrate improvements in reading fluency and reading comprehension. The findings of this study not only suggest that WM ability is closely related to reading skills, but also that WM training may serve as another route to further improve and develop students' literacy abilities.