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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Examining the effects of reward and punishment on incidental learning

Freedberg, Michael Vincent 01 May 2016 (has links)
Reward has been shown to improve multiple forms of learning. However, many of these studies do not distinguish whether reward directly benefits learning or if learning is boosted by modulation of top-down factors such as attention and motivation. The work outlined in this dissertation explores the modulatory effects of reward and punishment without directly manipulating top-down factors such as attention or motivation. We achieved this goal by studying the effects of reward and punishment on incidental learning – a branch of procedural learning where learning occurs without intention and through repetition. Our results reveal that reward is able to bolster incidental learning during the performance and learning of an associative task, even when awareness of how to achieve the reward is minimized (Experiments 1 and 2). However, a similar benefit was not observed in an analogous set of experiments examining the effect of punishment on incidental learning (Experiments 3 and 4). A direct comparison between the effect of reward and punishment on incidental learning revealed a significant advantage for rewarded combinations over punishment. However, this advantage was only observed when high cognitive (associative) demands were emphasized (Experiment 6), as opposed to high motor demands (Experiment 5). Finally, we explored the role of dopamine in the effect of reward on incidental learning. Because dopamine neuron dynamics have been implicated in both reward processing and in various forms of learning, we hypothesized that patients with Parkinson's disease (PD), who experience an accelerated rate of death of dopamine neurons, would experience impaired learning from rewards compared to healthy older adults. Experiment 7 revealed a significant impairment in reward-related incidental learning for patients with Parkinson's disease relative to comparisons. The amount of levodopa medication taken by PD patients predicted the effect of reward, demonstrating a potential link between dopamine levels and the effect of reward on incidental learning. Together, this dissertation demonstrates that 1) reward improves incidental learning, 2) reward may be an exceptional form of feedback, as opposed to punishments, and 3) dopamine levels may potentially drive the effect of reward on incidental learning
2

Development of high reliability construction work systems: Lessons from production practices of high performance work crews

January 2012 (has links)
abstract: The construction industry faces important performance problems such as low productivity, poor quality of work, and work-related accidents and injuries. Creating a high reliability work system that is simultaneously highly productive and exceptionally safe has become a challenge for construction practitioners and scholars. The main goal of this dissertation was to create an understanding of high reliability construction work systems based on lessons from the production practices of high performance work crews. High performance work crews are defined as the work crews that constantly reach and maintain a high level of productivity and exceptional safety record while delivering high quality of work. This study was conceptualized on findings from High Reliability Organizations and with a primary focus on lean construction, human factors, safety, and error management. Toward the research objective, this dissertation answered two major questions. First, it explored the task factors and project attributes that shape and increase workers' task demands and consequently affect workers' safety, production, and quality performance. Second, it explored and investigated the production practices of construction field supervisors (foremen) to understand how successful supervisors regulate task and project demands to create a highly reliable work process. Employing case study methodology, this study explored and analyzed the work practices of six work crews and crew supervisors in different trades including concrete, masonry, and hot asphalt roofing construction. The case studies included one exceptional and one average performing crew from each trade. Four major factors were considered in the selection of exceptional crew supervisors: (1) safety performance, (2) production performance, (3) quality performance, and (4) the level of project difficulty they supervised. The data collection was carried out in three phases including: (1) interview with field supervisors to understand their production practices, (2) survey and interview with workers to understand their perception and to identify the major sources of task demands, and (3) several close field observations. Each trade's specific findings including task demands, project attributes, and production practices used by crew supervisors are presented in a separate chapter. At the end the production practices that converged to create high reliability work systems are summarized and presented in nine major categories. / Dissertation/Thesis / Ph.D. Construction 2012
3

The Flexibility of Attentional Control in Selecting Features and Locations

Evans, Hsiao Chueh Kris 01 February 2010 (has links)
The visual processing of a stimulus is facilitated by attention when it is at an attended location compared to an unattended location. However, whether attentional selection operates on the basis of visual features (e.g., color) independently of spatial locations is less clear. Six experiments were designed to examine how color information as well as location information affected attentional selection. In Experiment 1, the color of the targets and the spatial distance between them were both manipulated. Stimuli were found to be grouped based on color similarity. Additionally, the evidence suggested direct selection on the basis of color groups, rather than selection that was mediated by location. By varying the probabilities of target location and color, Experiments 2, 3 and 4 demonstrated that the use of color in perceptual grouping and in biasing the priority of selection is not automatic, but is modulated by task demands. Experiments 5 and 6 further investigated the relationship between using color and using location as the selection basis under exogenous and endogenous orienting. The results suggest that the precise nature of the interaction between color and location varies according to the mode of attentional control. Collectively, these experiments contribute to an understanding of how different types of information are used in selection and suggest a greater degree of flexibility of attentional control than previously expected. The flexibility is likely to be determined by a number of factors, including task demands and the nature of attentional control.
4

Applying Cognitive Principles to the Delivery of Engineering Information by Different Mediums

Dadi, Gabriel B 01 January 2013 (has links)
Construction project performance and worker productivity are often tied to the availability and effective presentation of information, tools, materials, and equipment. While advancements in technology have improved much of the processes on a construction project, the medium of information dissemination at the construction work face has consistently relied on the use of two dimensional drawings and specifications. Industry initiatives are driving increased collaboration through three dimensional BIM (Building Information Modeling) models. However, the added dimension partially loses its effect when presented on a two dimensional computer monitor. Other computer forms of presentation intended for mobility (PDAs, laptops, and tablets) can be difficult to use in the field due to glare, durability in a harsh working environment, and the required skill level for effective use. Three dimensional (3D) physical printers now provide the capability to develop scaled and color models of a project directly from a BIM model. 3D physical printers represent a potential transformative change of providing engineering information to construction crews, but how to develop 3D models that leverage the cognitive benefits of viewing engineering information in a physical 3D form is unknown. The primary contribution to the overall body of knowledge of this dissertation is to scientifically examine the effect that different engineering information mediums have on an individual’s cognitive ability to effectively and accurately interpret spatial information. First, the author developed a robust scientific experiment for construction practitioners and students to complete. This experiment included outcomes measures on mental workload, cognitive demand, productivity, efficiency, demographics, and preferences. After collecting data, the author analyzed the outcomes through a series of statistical analyses to measure the differences between groups and quantify the affect and relationship among key variables. From the results, there are statistically significant improvements in productivity and efficiency of practitioners and students when using a physical model compared to two dimensional drawings and a three dimensional computer model. In addition, the average cognitive demand for a physical model was lower than the average cognitive demand for two dimensional drawings and three dimensional computer model.
5

A controlled resource approach to understanding the effects of feedback on learning

McLaughlin, Anne Collins 03 July 2007 (has links)
It is a testament to the complexity of learning that one hundred years of research on feedback has not produced universal prescriptions for training. Results are split in two directions; those recommending more feedback during training and those recommending less. Numerous theories that explain and predict certain feedback effects, but none explain the mixed findings in the literature. This has resulted in: a) no singular theory and b) little understanding of other factors that might affect the mechanism of feedback. The following series of studies systematically manipulated the cognitive load of the experimental task and measured learner working memory capacity. The overall question was whether forcing the learner to self-evaluate would result in more or less learning of a rule-based cognitive task and how this effect might be moderated by the working memory capacity of the learner and the load of the task to be learned. It was expected that high working memory capacity learners might learn more when difficulties were introduced for a simple task (via less supportive feedback). Instead, all groups not only learned more when receiving more support, the high working memory capacity learners appeared more able to utilize the additional feedback. Instead of providing their own support when feedback was minimal or lacking, high working memory capacity participants seemed best able to make use of the information provided in supportive feedback. Low working memory capacity participants seemed unable to either provide their own support when feedback was minimal or lacking, but also were not as able to make use of the information provided in more supportive feedback. The contribution of the current series of studies is an explanation of why and how appropriate level of feedback support can change based on the working memory capacity of the learner and demands of the task. Feedback can either impose a load upon the learner to self-evaluate or provide support for acquisition performance. Though learners may benefit from feedback neither too high nor too low, the current results indicate that additional feedback is most useful to those with the attentional resources available to utilize it.
6

Neurofunctional reorganization to support semantic processing during aging : an fMRI study

Haitas, Niobe 11 1900 (has links)
Le langage est dans son ensemble bien préservé pendant le vieillissement (Meyer & Federmeier, 2010) tandis que la mémoire sémantique peut même s'améliorer (Kavé, Samuel-Enoch, & Adiv, 2009; Prinz, Bucher, & Marder, 2004; Salthouse, 2009; Verhaegen & Poncelet, 2013 ; Wingfield & Grossman, 2006), malgré de nombreux changements neurophysiologiques se produisant dans le cerveau (Grady, Springer, Hongwanishkul, McIntosh, & Winocur, 2006 ; Kemper & Anagnopoulos, 1989 ; Wingfield & Grossman, 2006). Cette thèse se concentre sur la préservation de la mémoire sémantique dans le vieillissement, « l'acte cognitif d'accéder aux connaissances stockées sur le monde » (Binder, Desai, Graves et Conant, 2009) à travers une tâche de jugement sémantique manipulant le contrôle sémantique avec deux niveaux de demande (faible et élevé) et deux types de relations sémantiques (taxonomique et thématique). Nous avons développé une nouvelle tâche variant les niveaux de demande (faible et élevé) chez 39 adultes jeunes et 39 adultes âgés. Plus précisément, les objectifs de notre étude étaient 1) d'identifier si le vieillissement affecte l'activité cérébrale liée à la mémoire sémantique conformément aux prédictions du modèle CRUNCH, à travers une tâche de jugement sémantique à deux niveaux d'exigences. 2) de combler le vide de la littérature sur l'existence et l'évolution des hubs sémantiques dans le vieillissement, à la lumière des théories single hub et dual-hub, en évaluant l'effet du vieillissement sur le rôle des lobes temporaux antérieurs (ATL) et du jonction temporo-pariétale (TPJ) en tant que représentations neuronales des centres sémantiques responsables respectivement du traitement taxonomique et thématique. Une soumission par rapport pré-enregistré (registered report) a été utilisée pour ce projet de recherche. Nos participants, adultes plus jeunes et plus âgés, étaient globalement appariés en termes de réserve cognitive, plus précisément en ce qui concerne le niveau d'éducation et comme le montrent les questionnaires évaluant l'engagement dans des activités cognitivement stimulantes, les tests MoCA et WAIS-III. Les résultats comportementaux ont confirmé que la tâche varie correctement la difficulté de la tâche puisque les taux d'erreur et les temps de réponse (RT) augmentent de manière linéaire avec l'augmentation des exigences de la tâche, à savoir dans la condition de forte demande. Nous avons constaté que la participation à des activités stimulantes sur le plan cognitif avait un impact positif à la fois sur les RT de référence et sur la précision. Nous n’avons pas observé de différence statistiquement significative dans la précision entre les participants jeunes et plus âgés, quelle que soit la condition. Nous avons constaté que des scores plus élevés aux tests WAIS-III et PPTT étaient positivement corrélés avec la précision chez les personnes âgées. En termes de RT, nous avons observé une différence statistiquement significative entre les participants jeunes et plus âgés pour la tâche et les conditions de référence, les adultes plus âgés étant plus lents à répondre en général. Les RT augmentent linéairement avec l'âge du participant. En tant que telle, la tâche de mémoire sémantique a réussi à a) manipuler la difficulté de la tâche sur deux niveaux d'exigences et b) démontrer une performance comportementale invariante selon l'âge pour le groupe plus âgé, comme l'exige le test du modèle CRUNCH (Fabiani, 2012 ; Schneider-Garces et al., 2010). Pour l'objectif n°1, les tests cruciaux du modèle CRUNCH, l'interaction IRMf groupe par difficulté, n'étaient pas cohérents avec les prédictions du modèle. Malgré nos résultats comportementaux, lorsque nous avons comparé directement la condition de faible demande avec la condition de forte demande, il n'y avait pas de différence statistiquement significative dans l'activation entre les conditions de faible et de forte demande. Nous n'avons pas non plus obtenu d'interaction entre tranche d'âge et difficulté. Nous avons obtenu des interactions significatives en comparant les conditions de demande faible et élevée avec la ligne de référence. Au niveau neuronal, indépendamment de l'âge, la tâche de jugement de similarité sémantique a activé un large réseau bilatéral fronto-temporo-pariétal. Pour l'objectif n°2 concernant l'effet de relation sémantique, le contraste de la condition taxonomique avec la condition thématique directement n'a pas trouvé d'activation robuste à un seuil corrigé. La condition taxonomique a donné des résultats intéressants par rapport à la condition de base. Sept groupes distincts dans le cortex fronto-temporo-pariétal ont été activés dans les deux hémisphères, y compris les lobes temporaux antérieurs (ATL) et la jonction temporo-pariétale gauche (TPJ). De plus, l'activation était significative dans le gyrus supérieur frontal gauche, le gyrus angulaire gauche (AG) et le gyrus frontal inférieur (partie orbitale) sur l'hémisphère droit. Cette découverte pourrait être en partie conforme à la théorie du double-hub, qui propose que les ATL bilatéralement et le TPJ agissent comme des hubs sémantiques. Bien que nous n'ayons pas trouvé d'activation significative dans les ATL pendant la condition taxonomique et dans le TPJ pendant la condition thématique, nous avons cependant constaté que dans la condition taxonomique parmi les sept clusters significativement activés, l'activation dans le gyrus frontal supérieur gauche était significativement corrélée avec la performance dans la condition taxonomique pour les deux groupes d'âge. L'activation dans le gyrus temporal moyen droit était également corrélée à l'amélioration des performances, mais cela n'était pas significatif dans le groupe plus âgé. En ce qui concerne la condition thématique, par contraste avec condition de référence, dix groupes distincts ont été activés, y compris la jonction temporo-pariétale (TPJ), alors que les ATL n'ont pas été activés de manière robuste pendant la condition thématique. Plus précisément, les régions activées comprenaient bilatéralement le gyrus angulaire, le gyrus temporal moyen, le gyrus frontal inférieur (partie triangulaire) et le gyrus frontal moyen. Nous visons à poursuivre des analyses supplémentaires pour explorer la relation entre les exigences de la tâche, le type de relation sémantique et la réorganisation neurofonctionnelle liée à l'âge. Cependant, ces résultats relatifs à la préservation avec l'âge des capacités à traiter les différentes relations sémantiques de mots sont associés à un certain nombre de réorganisations neurofonctionnelles. Celles-ci peuvent être spécifiques au traitement de différentes relations sémantiques et de différentes demandes de tâches. Il reste à déterminer si cette réorganisation est induite par les changements structurels du cerveau avec l'âge, ou par l'utilisation accrue de telles relations sémantiques tout au long de la trajectoire de la vie. / Language overall is well preserved in aging (Meyer & Federmeier, 2010) whereas semantic memory may even improve (Kavé, Samuel-Enoch, & Adiv, 2009; Prinz, Bucher, & Marder, 2004; Salthouse, 2009; Verhaegen & Poncelet, 2013; Wingfield & Grossman, 2006), despite numerous neurophysiological changes taking place in the brain (Grady, Springer, Hongwanishkul, McIntosh, & Winocur, 2006; Kemper & Anagnopoulos, 1989; Wingfield & Grossman, 2006). The present study focuses on the preservation of semantic memory in aging, the ‘cognitive act of accessing stored knowledge about the world’ (Binder, Desai, Graves, & Conant, 2009) by means of a semantic judgment task manipulating semantic control with two demand levels (low and high) and two types of semantic relations (taxonomic-thematic). We used a novel task that varied task demands (low versus high) in 39 younger and 39 older adults. More specifically, the aims of this study was 1) to identify whether aging affects the brain activity subserving semantic memory in accordance with the CRUNCH predictions, through a semantic judgment task with two levels of demands (low and high). 2) To bridge the gap in the literature on the existence and evolution of semantic hubs in aging, in light of the dual and single-hub theories, by evaluating the effect of aging on the role of the Anterior Temporal Lobes (ATLs) and the Temporo-parietal junction (TPJ) as neural representations of the semantic hubs responsible for taxonomic and thematic processing, respectively. A submission by registered report was opted for this research project. Our participants, younger and older adults, were overall matched in regards to level of education and as shown in questionnaires assessing engagement in cognitively stimulating activities, MoCA and WAIS-III tests. The behavioral results confirmed that the task was successful in manipulating task difficulty, with error rates and RTs increasing with increasing task demands, namely in the high-demand condition. We found that engaging in cognitively stimulating activities impacted positively on both baseline RTs and accuracy and that higher scores on the WAIS-III and the PPTT tests were positively correlated with accuracy in older adults. There was no statistical difference in accuracy between younger and older participants regardless of the condition, so there was no age effect in accuracy. In terms of RTs, there was a statistically significant difference between younger and older participants for both the task and the baseline conditions, with older adults being slower to respond in general. RTs increased the more the participant’s age increased, which is in line with findings in the literature. As such, the semantic memory task was successful in a) manipulating task difficulty across two levels of demands and b) demonstrating age-invariant behavioural performance for the older group, as requires to test the CRUNCH model (Fabiani, 2012; Schneider-Garces et al., 2010). For objective no 1, the crucial test of CRUNCH model, the fMRI age group by task demand interaction was not found. We did not find statistically significant interaction neither between task demands and age group for RTs or accuracy, nor in regards to brain activation. At the neural level, independently of age, the semantic similarity judgment task activated a large network including bilateral inferior frontal, parietal, supplementary motor, temporal and occipital brain regions, which correspond overall with the semantic network, as suggested in the literature. Region of interest analyses demonstrated task demand effect in these regions, most notably in the left and right inferior frontal gyrus, the left posterior middle temporal gyrus, the posterior inferior temporal gyrus and the pre-frontal gyrus, regions which are typically associated with semantic control requirements. We did not find any significant interactions between task demands and activation in the regions of interest either. Several possible reasons may justify the lack of findings as predicted by the CRUNCH hypothesis. For objective no 2 in regards to the semantic relation effect, the contrast of the taxonomic with the thematic condition directly did not produce any robust activation at a corrected threshold. The taxonomic condition yielded interesting results when contrasted with the baseline one. Seven distinct clusters in the fronto-temporo-parietal cortex were activated across the two hemispheres, including the anterior temporal lobes (ATLs) and the left temporo-parietal junction (TPJ). Additionally, activation was significant in the left frontal syperior gyrus, the left angular gyrus (AG) and the inferior frontal gyrus (orbital part) on the right hemisphere. This finding could be partly in line with the dual-hub theory, that proposes that the ATLs bilaterally and the TPJ act as semantic hubs. Though we did not find the expected double dissociation e.g., significant activation in the ATLs during the taxonomic condition only and in the TPJ during the thematic condition only, we found however that in the taxonomic condition among the seven significantly activated clusters, activation in the left superior frontal gyrus was significantly correlated with performance in both age groups. Activation in the right middle temporal gyrus was also correlated with improved performance, but this was not significant in the older group. During the thematic condition, when contrasted with baseline, ten distinct clusters were activated, including the temporo-parietal junction (TPJ), whereas the ATLs were not robustly activated during the thematic condition. We aim to pursue additional analyses to explore the relation between task demands, type of semantic relation and age-related neurofunctional reorganization. However, these results in relation to the preservation with age of the abiliites to process the different semantic word relations is associated with a number of neurofunctional reorganizations. These can be specific to the processing of different semantic relations and different task demands. Whether this reorganization is induced by the structural changes in the brain with age, or by the enhanced use of such semantic relations along the trajectory of life is still under exploration.

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