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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.
141

Gaze Control as a Marker of Self-other Differentiation: Implications for Sociocognitive Functioning and Close Relationship Quality

Petrican, Raluca 13 June 2011 (has links)
An individual`s eyes provide a wealth of information during social interactions. The present research investigates the social adjustment implications of one gaze behaviour, specifically, shared attention, which is the tendency to follow an interlocutor`s directed gaze to attend to the same object or location. Recent clinical research suggested that gaze control reflects the capacity to differentiate self from other at the attentional level, since patient populations with poor gaze control abilities (i.e., schizophrenic patients) were also found to exhibit difficulty in differentiating between the self and another agent. Four studies were conducted to examine whether flexible gaze following behavior, specifically the ability to inhibit gaze-following, when the situation warrants, would be positively linked with two markers of adaptive social functioning: sociocognitive abilities and self-close other(s) differentiation. Based on previous research that gaze cues linked to upright (but not inverted) faces trigger reflexive gaze following mechanisms, an upright face condition was used to assess social cueing mechanisms and an inverted face condition, as a control for non-social cueing mechanisms in a gaze control task with realistic (Study 2) and schematic faces (Studies 1, 3, and 4). Studies 1-4 showed that more flexible gaze following behavior predicted superior sociocognitive abilities, as indexed by higher capacity to infer the mental states of others in both young and older adults (Studies 1-3), as well as in clinical populations (i.e., Parkinson’s Disease [PD] patients, Study 4). Studies 2-4 further revealed that poorer gaze control predicted decreased self-close other differentiation in both younger and older adults. In Study 2, poorer gaze control performance characterized young adults from enmeshed family systems, which allow limited private space and emotional autonomy. In Studies 3 and 4, poorer gaze control predicted decreased cognitive-affective differentiation from one’s spouse and lower marital quality in healthy elderly couples (Study 3) and elderly couples, where one spouse had PD (Study 4). The present findings argue for the existence of a unified sociocognitive network, perpetually shaped by one’s interpersonal history, and which encompasses perceptual mechanisms, specialized for face and gaze processing and higher-order cognitive mechanisms, specialized for processing the meaning (s) of social environments.
142

Competition in Visual Working Memory

Emrich, Stephen Michael 06 December 2012 (has links)
The processing of information within the visual system is limited by several cognitive and neural bottlenecks. One critical bottleneck occurs in visual working memory (VWM), as the amount of information that can be maintained on-line is limited to three to four items. While numerous theories have addressed this limited capacity of VWM, it is unclear how processing bottlenecks in the initial selection and perception of visual information affect the number or precision of representations that can be maintained in VWM. The purpose of this dissertation was to examine whether early competition for resources within the visual system limits the number or precision of representation that can be maintained in VWM. To establish whether competitive interactions affect VWM, Chapters 1 – 4 tested whether performance on VWM tasks was related to the distance between memory items. The results of these experiments reveal that when objects are presented close together in space, VWM performance is impaired relative to when those same objects are presented further apart. Using a three-component model of continuous responses in a recall task, Chapters 3 – 4 demonstrated that the distance between objects primarily affects the precision of responses, and increases the number of non-target errors. Chapter 5 extended these findings to distractors, demonstrating that multiple distractors affect the precision and accuracy of VWM responses. Chapters 6 – 7 tested how attentional selection can bias memory representations, revealing that objects that are given high attentional priority were reported with greater precision. Finally, Chapters 8 and 9 examined bias-signals as a potential source of individual differences in VWM performance, revealing that high-performers have more precise representations of sub-capacity representations than low-performers. Together, these results reveal that VWM performance is limited by competition for representation within the visual system, and that attention plays a critical role in resolving competition and consequently, determining the contents of VWM.
143

Cognitive Abilities Underlying the Bilingual Advantage in Set Shifting

Nguyen, Thien-Kim 11 January 2012 (has links)
Prior research has demonstrated that bilinguals outperform monolinguals on tasks requiring set shifting – that is, the ability to shift between different ways of thinking about an object or situation. For example, bilingual children have been shown to outperform monolingual controls on false-belief tasks and on the Dimensional Change Card Sort (DCCS) task. The present study aimed (a) to examine whether the bilingual advantage in false-belief and DCCS tasks can be replicated when accounting for languages/cultures and socio-economic status and (b) to determine whether inhibitory control, metarepresentation, and/or working memory underlie the advantage, if any exists. Three language groups (24 English monolingual, 24 French monolingual, and 24 English-French bilingual preschoolers) were tested on the following tasks: false-belief (FB) tasks, the DCCS task, an inhibitory control task (Stroop task), a metarepresentation task (Identity Statements task), a working memory task (Backward Word Span), and receptive language proficiency tests. Socio-economic status was measured through a parental questionnaire containing questions about parental income and education. Results showed that the three language groups were equivalent on socio-economic measures. Despite having significantly lower language proficiency scores, bilinguals’ raw scores on FB and DCCS tasks did not differ from monolinguals’ raw scores. After statistically controlling for language proficiency and age, bilinguals had significantly higher FB scores, but did not differ from monolinguals on DCCS scores. Analyses were then performed to determine whether inhibitory control, metarepresentation, and/or working memory help bilinguals “do more” in FB “with less” language proficiency. Working memory emerged as the likely candidate that compensates for the negative effect of bilingual children’s low language proficiency on FB performance because, after controlling for age and language proficiency, it was the only cognitive ability that fulfilled both criteria: (a) its measure correlated significantly with FB and (b) there was a bilingual advantage over both monolingual groups in the measure. A mediation analysis confirmed that the working memory measure significantly mediates the relation between bilingual status and FB while controlling for age and language proficiency. Both components of the working memory measure – that is, understanding of task instructions and maintenance/manipulation capacity – mediate this relation.
144

Investigating Spatial Working Memory and Saccadic Remapping Processes in Healthy Young and Elderly Participants

Goldberg, Lana January 2009 (has links)
Additional cognitive deficits, including impairments in spatial working memory and/or saccadic remapping processes, have recently been implicated in unilateral neglect – a neurological condition classically characterized as a disorder of attention. The interactions between saccadic remapping and three memory processes (position memory, object memory and object-location binding) were investigated in healthy young (n=27) and elderly (n=20) participants to establish a baseline of comparison for future use with neglect patients and to study the effects of aging on these processes. In a computerized task, participants were instructed to first detect a target, and then hold in memory either its position, identity or both over a delay period. Subsequently, participants were tested on their memory for that particular task. The saccadic remapping component was introduced at the onset of the delay period with the fixation cross shifting either to the left, or right, requiring participants to remap the visual array into either right or left space, or remaining in the centre of the screen (i.e., no remapping condition). In the position memory and object-location binding task, a consistent cost to memory performance was found when remapping right only for the young participants. Overall the elderly did not perform any of the tasks involving a position memory component as well as the young participants and showed spatial asymmetries in the target detection task. The lack of an effect of remapping in the elderly group may be due to a general decrement in performance. These results are discussed in terms of hemispheric asymmetries and cognitive theories of aging.
145

Self-Esteem, Failure Feedback, and Physiological Reactivity: Implications for Working Memory and Aggression

Ryan, John Patrick 17 July 2009 (has links)
Research has recently begun to focus on separable conscious and subconscious aspects of self-esteem. Meanwhile, research on aggressive behavior has found that some individuals with high self-esteem are more prone to aggressive behavior. Based on a biopsychosocial approach, research has shown that appraisals of threat/challenge are marked by distinct physiological responses – threat appraisals are marked by activation of the hypothalamic-pituitary-adrenal axis, whereas challenge appraisals are marked by activation of the sympathetic adrenal-medullary axis. The present study examines the relationship between failure feedback, implicit and explicit self-esteem, appraisals, working memory and aggression in a series of three experiments. Experiment 1 examined the impact of failure feedback on stress physiology and found that individuals who displayed a physiological response to failure feedback consistent with a challenge response, as indicated by an increase in blood pressure without a concurrent increase in salivary cortisol, were the most likely group to become aggressive. Experiment 2 examined the relationships between implicit and explicit self-esteem in predicting aggressive behavior. Implicit self-esteem predicted behavioral inhibition in response to negative feedback such that higher implicit self-esteem was associated with fewer behavioral inhibition errors. In Experiment 3, threat/challenge motivations were manipulated to determine their impact on working memory performance. Increases in feelings of threat were associated with greater working memory performance, whereas increases in feelings of challenge were associated with decreases in working memory performance. The present study is the first to examine aggression in the context of threat/challenge appraisal responses. Overall, this study suggests that appraisals and physiology can assist in predicting aggressive behavior, although the cognitive mechanism by which this occurs remains elusive.
146

Räkna - Läsa - Minnas : Vilka samband finns det? / Calculate – Read – Remember : What correlation is there?

Thompson, Helen, Petersson, Yvonne January 2011 (has links)
Syftet med studien är att undersöka samband som visas tydligt hos elever i både matematiksvårigheter samt fonologiska svårigheter. Studien har genomförts på elever i årskurs 7 som uppvisat matematiska såväl som fonologiska svårigheter. Resultatet baseras på en filmad observation där eleverna fått lösa ett urval uppgifter konstruerade utifrån svårigheter gällande grundläggande taluppfattning och aritmetik. Elever med fonologiska svårigheter såväl som bristande arbetsminne visar sig ha svårigheter när det gäller att automatisera tabellkunskap såväl som utföra beräkningar gällande de fyra räknesätten. / The purpose of the study is to research what correlation is apparent in students with both mathematical and phonological difficulties. The study has been conducted with 7th grade students who have shown both mathematical and phonological difficulties. The result is based on a filmed observation where the students solved a selection of tasks constructed based on problems with basic number sense and arithmetic. Students with phonological difficulties as well as inadequate working memory are showing problems when it comes to automated knowledge of the multiplication table as well as performing calculations concerning arithmetic.
147

Investigating Spatial Working Memory and Saccadic Remapping Processes in Healthy Young and Elderly Participants

Goldberg, Lana January 2009 (has links)
Additional cognitive deficits, including impairments in spatial working memory and/or saccadic remapping processes, have recently been implicated in unilateral neglect – a neurological condition classically characterized as a disorder of attention. The interactions between saccadic remapping and three memory processes (position memory, object memory and object-location binding) were investigated in healthy young (n=27) and elderly (n=20) participants to establish a baseline of comparison for future use with neglect patients and to study the effects of aging on these processes. In a computerized task, participants were instructed to first detect a target, and then hold in memory either its position, identity or both over a delay period. Subsequently, participants were tested on their memory for that particular task. The saccadic remapping component was introduced at the onset of the delay period with the fixation cross shifting either to the left, or right, requiring participants to remap the visual array into either right or left space, or remaining in the centre of the screen (i.e., no remapping condition). In the position memory and object-location binding task, a consistent cost to memory performance was found when remapping right only for the young participants. Overall the elderly did not perform any of the tasks involving a position memory component as well as the young participants and showed spatial asymmetries in the target detection task. The lack of an effect of remapping in the elderly group may be due to a general decrement in performance. These results are discussed in terms of hemispheric asymmetries and cognitive theories of aging.
148

The effects of gaming on working memory, inattention, reading and math : A longitudinal study

Sjöwall, Douglas January 2010 (has links)
Previous research has shown both positive and negative effects of gaming on academic and cognitive performance. The purpose of this study was to assess the effect of gaming on development of working memory (WM), inattention, reading and math ability using a longitudinal design. A randomly chosen sample of 335 (168 girls) 6–25 year olds performed tests of visuo-spatial and verbal WM, reading and math ability twice, with a two year interval. Gaming and inattention were assed with questionnaires. Time spent gaming did not affect development of any of the variables. However, game category did correlate with development of visuo-spatial WM, with action-gamers having a more favourable development. There was, however, no positive interaction with more time spent gaming for action-gamers. These results suggest that gaming should not be regarded as a damaging leisure activity. There could instead be some positive effects of gaming, but future research should try to identify the aspects of gaming contributing to this effect.
149

Testing executive function models of ADHD and its comorbid conditions: A latent variable approach

Lee, Dong Hyung 01 November 2005 (has links)
Current theoretical models of ADHD (i.e., Disinhibition Model: Barkley, 1997; Working Memory Model: Rapport et al., 2001) conceptualize ADHD as the disorder of executive function (EF) with some variation in their emphases on particular components of the broadly-defined EF (e.g., working memory vs. inhibition) and in their postulated relationships with ADHD symptoms. Although these models provide systematic accounts of the manifestation of ADHD, they have not been extensively tested from an empirical standpoint. Moreover, despite the fact that ADHD is highly comorbid with other additional conditions such as learning and behavioral problems and EF deficits are found in individuals with these conditions as well as in those with ADHD, current EF models have not specified the developmental relationship between ADHD and its comorbid conditions. This study was: (1) to examine the extent to which two current models of ADHD are supported in a sample of 102 adults; (2) to present an ??integrated?? model by combining two current models of ADHD and linking them to recent research findings on two common comorbid conditions with ADHD (i.e., reading difficulty and substance abuse); and (3) to test and revise such an integrated model in the light of data using a latent variable analysis. Major findings provided a strong support for the Working Memory Model with a lesser degree of support for the Disinhibition Model. Preliminary evidence of working memory as the primary deficit in ADHD was also obtained in the present sample. Finally, the integrated EF model and its revised model (final model) demonstrated a very good fit to the data. These findings suggest that the integrated model provides a unified account of how EF deficits contribute to the manifestation of ADHD symptoms and comorbid conditions with ADHD. Given some limitations (e.g., sample size and scope) of the present study, current findings need to be replicated.
150

Executive function processes: inhibition, working memory, planning and attention in children and youth with Attention Deficit Hyperactivity Disorder

Wolfe, Monica Eileen 12 April 2006 (has links)
This study examines the roles of inhibition, attention, working memory, and planning in youth with and without ADHD. As conceptualized in theories of attention, inhibition, and working memory, difficulties with these executive processes interact to manifest in the behavioral syndrome(s) of ADHD. Barkley (1997) proposed disinhibition as the primary deficit of ADHD. Rapport, Chung, Shore, Denney, & Isaacs, (2000) theorized that ADHD results from a primary deficit in working memory. Mirsky (1987) proposed a model of attention which children with ADHD have deficits in abilities to focus/execute, encode and sustain attention. Posner and Petersen (1990) proposed that three attentional networks are responsible for attentional processes and those children with ADHD have deficits in the vigilance network. To investigate the contributions of inhibition, working memory, attention, and planning in executive dysfunction in children with ADHD, measures were selected from factor analytic studies. Children with ADHD-Combined Type demonstrated poorer inhibition and working memory than children with no diagnosis after controlling for IQ effects. No differences in planning and attention were indicated after controlling for IQ effects. However, a predictive discriminant analysis indicated that none of the executive processes contributed to the prediction of group membership. Given correlational and predictive discriminant analysis results, further analyses were conducted to investigate the contribution of the measures selected for the domains. The theoretical model did not represent a good fit of the data. A three-factor model indicated the best representation suggesting that inhibition and attention were not separable. There were no group differences with the revised measurement model for inhibition/attention, working memory and planning. Taken together, results indicated measures originally selected to tap executive function may not be clean measures of inhibition, working memory, planning, or attention processes. In addition, recently proposed theories overlap and conceptualize the multiple constructs involved in ADHD with a variety of methodologies, further contributing to difficulties in interpreting results and measurement issues.

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