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Artificial neural networks (ANNs) and logic programs have both been suggested as means of modelling human cognition. While ANNs are adaptable and relatively noise resistant, the information they represent is distributed across various neurons and is therefore difficult to interpret. On the contrary, symbolic systems such as logic programs are interpretable but less adaptable. Human cognition is performed in a network of biological neurons and yet is capable of representing symbols, and therefore an ideal model would combine the strengths of the two approaches. This is the goal of Neural-Symbolic Integration [4, 16, 21, 40], in which ANNs are used to produce interpretable, adaptable representations of logic programs and other symbolic models. One neural-symbolic model of reasoning is SHRUTI [89, 95], argued to exhibit biological plausibility in that it captures some aspects of real biological processes. SHRUTI's original developers also suggest that further biological plausibility can be ascribed to the fact that SHRUTI networks can be represented by a model of genetic development [96, 120]. The aims of this thesis are to support the claims of SHRUTI's developers by producing the first such genetic representation for SHRUTI networks and to explore biological plausibility further by investigating the evolvability of the proposed SHRUTI genome. The SHRUTI genome is developed and evolved using principles from Generative and Developmental Systems and Artificial Development [13, 105], in which genomes use indirect encoding to provide a set of instructions for the gradual development of the phenotype just as DNA does for biological organisms. This thesis presents genomes that develop SHRUTI representations of logical relations and episodic facts so that they are able to correctly answer questions on the knowledge they represent. The evolvability of the SHRUTI genomes is limited in that an evolutionary search was able to discover genomes for simple relational structures that did not include conjunction, but could not discover structures that enabled conjunctive relations or episodic facts to be learned. Experiments were performed to understand the SHRUTI fitness landscape and demonstrated that this landscape is unsuitable for navigation using an evolutionary search. Complex SHRUTI structures require that necessary substructures must be discovered in unison and not individually in order to yield a positive change in objective fitness that informs the evolutionary search of their discovery. The requirement for multiple substructures to be in place before fitness can be improved is probably owed to the localist representation of concepts and relations in SHRUTI. Therefore this thesis concludes by making a case for switching to more distributed representations as a possible means of improving evolvability in the future.

Rural schools experience difficulty in filling teaching positions at higher rates than non-rural schools. Recruiting and retaining teachers are critical in these districts; however, because the term “rural” is variable, a one-size-fits-all response is not possible. Rural communities tend to be geographically remote, have a low critical mass of students with distinct disabilities, and have relatively few resources to provide differential support for students. In this context, special educators may find themselves in circumstances where they operate as general specialists who are responsible for addressing a broad range of student needs without the support of other related service providers (e.g., school psychologists, curriculum specialists, school counselors, speech and language pathologists). Garwood’s article provides a catalyst to consider ecological system factors that affect burnout, attrition, and, as a consequence, instruction, particularly for students with disabilities. In this response, we view this issue from a perspective of rural schools, where the system contexts are varied and directly impact teacher-level variables, such as the ability to implement evidence-based practices (EBPs) with fidelity. Taking a developmental systems approach, we describe what makes rural settings unique and how these characteristics interact with the critical features of EBPs, as well as suggest how preparation and induction programs might better prepare and sustain teachers to adapt instruction to these rural contexts. We conclude with implications for practice and policy.

The South African context, in particular, is characterized by a definite need for the facilitation of the development of the youth in a more positive trajectory. Family structures are not always robust enough to support the positive development of the youth, owing to the demands made on single–parent families, amongst other reasons. Community structures may also be less supportive of the development of the youth, because of the impact of the changes associated with the transitional phase of the country during the past sixteen years (Meehan, Peirson & Fridjhon, 2007). Furthermore, young people under the age of 15 years comprise almost a third of the total South African population (Statistics South Africa, 2009), and in the future, they will have to be prepared for an adulthood faced with previously unknown challenges (United Nations Population Fund). The importance of the development of the youth, in order to enable them to contribute to their country in future, is acknowledged by the South African Governement (National Youth Commission website). This study was conducted within the parameters of the newly developing positive youth development (PYD) paradigm. The empirical level of this paradigm is well represented in the literature, indicating that the content areas, or the “what” of PYD, have been well elucidated. However, there is a lack of theory, especially with regard to models describing developmental change (Larson et al., 2004), and evaluation of interventions aiming at the facilitation of PYD. In order to contribute to the answering of the questions regarding the “how” of development, this study had the following main aims: a) the compilation of a theoretical model, describing developmental change in the youth; b) the operationalization of this model for intervention purposes; and c) the evaluation of a programme and the model on which it is based. The study is reported on in an article format, and comprises a total of three articles. The first article focuses on the process of the compilation of a theoretical model by means of: a) the construction of a comprehensive meta–theoretical matrix, b) the integration of theory that features in the PYD literature, and c) the expansion of the latter with theory from other compatible sub–disciplines in psychology. The resultant Positive Youth Development Intervention (PYDI) model provides a process–related description of developmental change ? and is one of the first models to do so. The second article describes the operationalization of the PYDI model, by means of an indication of the relevant constructs, phenomena and processes to be facilitated. Although recent research points to a relation between PYD and self–regulation, there has been no model, describing the role of self–regulation in the facilitation of the positive development of the youth. This study adapted a model from an educational context (Heckhausen & Gollwitzer, 1987 (as cited in Boekaerts & Niemivirta, 2005)), in order to describe the regular self–regulatory processes constituting the bi–directional interactions between the youth and their primary life contexts, as proposed by developmental systems theory (Lerner, 1998), the meta–theory to PYD (King et al., 2005). A further specifc contribution is that the presentation aspects of the programme material, aimed at facilitating the integration thereof, are addressed on a theoretical level. The third article describes the evaluation of the PYDI model and programme, with young adolescents in a school in a rural area as participants. A mixed–methods study, which has been shown to render much richer information than a quantitative study alone, was applied. Although the quantitative data did not prove the success of the programme, the qualitative data suggested that some aspects of self–regulation had indeed been facilitated successfully. A second follow–up assessment, conducted seventeen months later, indicated that certain skills had only become internalized by that time, suggesting that the implementation and evaluation of such a programme should be expanded over an extended time–frame. This study has contributed to the level of theory of PYD, by indicating, a) the lacunae, and b) that theory in compatible sub–disciplinary paradigms could be used in order to devise workable models for PYD. Furthermore, the process–related nature of the PYDI model and programme, owing to its adaptability to different needs, may be adapted and extended to be applicable to the needs of the diverse South African population. Recommendations regarding future application and research, especially within the South African context, have also been put forward in the study. / Thesis (Ph.D. (Psychology))--North-West University, Potchefstroom Campus, 2011.

The South African context, in particular, is characterized by a definite need for the facilitation of the development of the youth in a more positive trajectory. Family structures are not always robust enough to support the positive development of the youth, owing to the demands made on single–parent families, amongst other reasons. Community structures may also be less supportive of the development of the youth, because of the impact of the changes associated with the transitional phase of the country during the past sixteen years (Meehan, Peirson & Fridjhon, 2007). Furthermore, young people under the age of 15 years comprise almost a third of the total South African population (Statistics South Africa, 2009), and in the future, they will have to be prepared for an adulthood faced with previously unknown challenges (United Nations Population Fund). The importance of the development of the youth, in order to enable them to contribute to their country in future, is acknowledged by the South African Governement (National Youth Commission website). This study was conducted within the parameters of the newly developing positive youth development (PYD) paradigm. The empirical level of this paradigm is well represented in the literature, indicating that the content areas, or the “what” of PYD, have been well elucidated. However, there is a lack of theory, especially with regard to models describing developmental change (Larson et al., 2004), and evaluation of interventions aiming at the facilitation of PYD. In order to contribute to the answering of the questions regarding the “how” of development, this study had the following main aims: a) the compilation of a theoretical model, describing developmental change in the youth; b) the operationalization of this model for intervention purposes; and c) the evaluation of a programme and the model on which it is based. The study is reported on in an article format, and comprises a total of three articles. The first article focuses on the process of the compilation of a theoretical model by means of: a) the construction of a comprehensive meta–theoretical matrix, b) the integration of theory that features in the PYD literature, and c) the expansion of the latter with theory from other compatible sub–disciplines in psychology. The resultant Positive Youth Development Intervention (PYDI) model provides a process–related description of developmental change ? and is one of the first models to do so. The second article describes the operationalization of the PYDI model, by means of an indication of the relevant constructs, phenomena and processes to be facilitated. Although recent research points to a relation between PYD and self–regulation, there has been no model, describing the role of self–regulation in the facilitation of the positive development of the youth. This study adapted a model from an educational context (Heckhausen & Gollwitzer, 1987 (as cited in Boekaerts & Niemivirta, 2005)), in order to describe the regular self–regulatory processes constituting the bi–directional interactions between the youth and their primary life contexts, as proposed by developmental systems theory (Lerner, 1998), the meta–theory to PYD (King et al., 2005). A further specifc contribution is that the presentation aspects of the programme material, aimed at facilitating the integration thereof, are addressed on a theoretical level. The third article describes the evaluation of the PYDI model and programme, with young adolescents in a school in a rural area as participants. A mixed–methods study, which has been shown to render much richer information than a quantitative study alone, was applied. Although the quantitative data did not prove the success of the programme, the qualitative data suggested that some aspects of self–regulation had indeed been facilitated successfully. A second follow–up assessment, conducted seventeen months later, indicated that certain skills had only become internalized by that time, suggesting that the implementation and evaluation of such a programme should be expanded over an extended time–frame. This study has contributed to the level of theory of PYD, by indicating, a) the lacunae, and b) that theory in compatible sub–disciplinary paradigms could be used in order to devise workable models for PYD. Furthermore, the process–related nature of the PYDI model and programme, owing to its adaptability to different needs, may be adapted and extended to be applicable to the needs of the diverse South African population. Recommendations regarding future application and research, especially within the South African context, have also been put forward in the study. / Thesis (Ph.D. (Psychology))--North-West University, Potchefstroom Campus, 2011.