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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

Changes in Parent-Child Relationships as a Result of Family Therapy

Kinney, Delane R. 05 1900 (has links)
The problem with which this study is concerned is whether pathogenic parental patterns which precipitate and maintain children's maladjustment can be ameliorated through family therapy. Specifically, this investigation focused on how parental attitudes and sons' perceptions of parental attitudes are altered by therapy.
2

Studying Journal Articles under Time Pressure

Meschino, Lisa January 2011 (has links)
The purpose of this dissertation is to understand how students distribute their attention while reading academic journal articles under time pressure. Given that most of the reading done in university is commonly time-sensitive and task-dependent, this dissertation explores how students actually shift their attention across the discrete sections of a journal article in the available time to identify and extract task-relevant information. Addressing gaps in the literature, the experiments in this dissertation observe the impact of the following three factors on strategic shifts in attention during study: (1) varied time conditions; (2) the presence/absence of summary information; and (3) the experience of the reader in terms of education level. The experimental methods used in this series of studies are consistent across all three chapters. Participants are given two 5-page academic journal articles to read on cognitive psychology for an impending test. Participants’ eye movement data are analyzed for the total adjusted viewing time the eyes spend in each section of the article, i.e., viewing time in each section was divided by the number of words in each section. The experiments in Chapter 2 examine overt attention when studying with and without a time constraint. Participants were given either 2 minutes of study time or unlimited study time. Analyses of the eye movement data reveal a reduced reading effect both when study time is restricted and unlimited. Specifically, the results showed that as time progresses, participants tend to read less and skim more, with the largest amount of adjusted time being spent on the Abstract. Chapter 3 examines further the apparent importance of the Abstract when reading under time constraint. It investigates whether people allocate more attention to the Abstract relative to other sections of the journal article based on its position or its summary content. Also, Chapter 3 explores whether the presence of an Abstract impacts what people read next in the article. Participants are given a limited time in which to read one of two versions of the articles to read, one version with an Abstract, the other without. The findings show that position, rather than summary content, seems to explain the amount of adjusted viewing time on the Abstract. Additionally, the summary information contained in an Abstract impacts what people read next in the article. Chapter 4 examines the extent to which participants’ education level impacts their use of a skimming strategy for studying. Here, participants form three different groups based on their year of study: graduates, senior undergraduates (3rd and 4th year), and junior undergraduates (1st and 2nd year). Overall, the results suggest that, when studying journal articles under time pressure, skimming behaviour changes from a primarily linear-skimming strategy (reading from beginning to end) to a more targeted-skimming strategy with increased education level. Finally, in the General Discussion in Chapter 5, a summary of the findings of this dissertation is considered in light of the literature on complex factors that impact attention and information-gain. The chapter also outlines hypotheses for future testing of overt attention while reading journal articles under time pressure.
3

Studying Journal Articles under Time Pressure

Meschino, Lisa January 2011 (has links)
The purpose of this dissertation is to understand how students distribute their attention while reading academic journal articles under time pressure. Given that most of the reading done in university is commonly time-sensitive and task-dependent, this dissertation explores how students actually shift their attention across the discrete sections of a journal article in the available time to identify and extract task-relevant information. Addressing gaps in the literature, the experiments in this dissertation observe the impact of the following three factors on strategic shifts in attention during study: (1) varied time conditions; (2) the presence/absence of summary information; and (3) the experience of the reader in terms of education level. The experimental methods used in this series of studies are consistent across all three chapters. Participants are given two 5-page academic journal articles to read on cognitive psychology for an impending test. Participants’ eye movement data are analyzed for the total adjusted viewing time the eyes spend in each section of the article, i.e., viewing time in each section was divided by the number of words in each section. The experiments in Chapter 2 examine overt attention when studying with and without a time constraint. Participants were given either 2 minutes of study time or unlimited study time. Analyses of the eye movement data reveal a reduced reading effect both when study time is restricted and unlimited. Specifically, the results showed that as time progresses, participants tend to read less and skim more, with the largest amount of adjusted time being spent on the Abstract. Chapter 3 examines further the apparent importance of the Abstract when reading under time constraint. It investigates whether people allocate more attention to the Abstract relative to other sections of the journal article based on its position or its summary content. Also, Chapter 3 explores whether the presence of an Abstract impacts what people read next in the article. Participants are given a limited time in which to read one of two versions of the articles to read, one version with an Abstract, the other without. The findings show that position, rather than summary content, seems to explain the amount of adjusted viewing time on the Abstract. Additionally, the summary information contained in an Abstract impacts what people read next in the article. Chapter 4 examines the extent to which participants’ education level impacts their use of a skimming strategy for studying. Here, participants form three different groups based on their year of study: graduates, senior undergraduates (3rd and 4th year), and junior undergraduates (1st and 2nd year). Overall, the results suggest that, when studying journal articles under time pressure, skimming behaviour changes from a primarily linear-skimming strategy (reading from beginning to end) to a more targeted-skimming strategy with increased education level. Finally, in the General Discussion in Chapter 5, a summary of the findings of this dissertation is considered in light of the literature on complex factors that impact attention and information-gain. The chapter also outlines hypotheses for future testing of overt attention while reading journal articles under time pressure.
4

Associations between Fear of Negative Evaluation and Covert and Overt Attention Bias Through Eye-Tracking and Visual Dot Probe

Capriola, Nicole N. 26 March 2018 (has links)
Social Anxiety Disorder is characterized by irrational and persistent fears of potential evaluation and scrutiny by others. For socially anxious youth, the core, maladaptive cognition is fear of negative evaluation (FNE). Whereas Cognitive Behavioral Therapy (CBT) targets remediation of intense and unfounded FNE, Attention Bias Modification Treatment (ABMT) targets attention bias. The degree to which FNE and biased attention are related processes is unknown. This study sought to assess the relationship between FNE and two indices of attention bias (dot probe and eye-tracking). In addition, this study examines differences in attention bias between a clinically confirmed group of youth SAD and healthy controls. A significant group difference in average latency to fixate on angry faces was found [F(1,65) = 31.94, p < .001, ηp2 = .33]. However, the pattern was not consistent across the other attention bias metrics (i.e., dot probe bias scores and first fixation direction percentage towards angry faces). In addition, associations between FNE and the attention bias metrics were not statistically significant in either group. Future directions and implications of these findings within the context of refinements to existing interventions are discussed. / Master of Science / Social Anxiety Disorder (SAD) is characterized by irrational and persistent fears of potential evaluation and scrutiny by others. For socially anxious youth, a main feature of the disorder is fear of negative evaluation (FNE). Whereas Cognitive Behavioral Therapy (CBT) targets FNE, Attention Bias Modification Treatment (ABMT) targets attention bias. However, the degree to which FNE and biased attention are related processes has not been studied. This study examined the relationship between FNE and two indices of attention bias (dot probe and eye-tracking). This study also examines differences in attention bias between a youth with SAD and healthy youth (no psychological diagnoses). Group differences were found for only one attention bias measure (i.e., youth with SAD were quicker to look at anger faces relative to non-anxious youth). In addition, associations between FNE and the attention bias metrics were not statistically significant in either group. Future directions of these findings are discussed.
5

Factors regulating the bottom-up guidance of overt visual attention under natural conditions

Acik, Alper 22 June 2015 (has links)
The main goal of the present thesis is to contribute to the study of overt visual attention under natural conditions. All publications included in the thesis employ eye-tracking methodology and local image feature analysis. The particular scientific question posed, if all parts of the thesis are considered together, can be formulated as: What experimental (i.e. experimenter controlled) and pseudo-experimental (e.g. demographic characteristics such as age) variables define, quantify and set limits for bottom-up determinants of fixation election? In this summary, I will bring together the answers to this question obtained during the course of the thesis and try to elucidate their significance in relation to the puzzles and riddles of eye movement research. After presenting an overview of the field, I will show how and to what extent fixation selection is altered as a function of age and as certain stimulus components are modified. Finally, I will argue that visual attention involves varying degrees of reliance on bottom-up cues according to the attending agent’s knowledge that is relevant in a given context.
6

High- and low-level factors in visual attention

Kaspar, Kai 17 July 2013 (has links)
The visual sense has outstanding importance for humans’ interaction with the environment and visual attention is the key mechanism that bundles our limited cognitive resources in order to enhance the perceptual processing of the most relevant environmental features at a certain point in time. Eye-Tracking technology enables us to accurately observe peoples’ eye movement behavior i.e. overt attention. In the last decade, overt attention on real-world scenes gained increasing popularity in vision research. The higher ecological validity of such scenes in combination with a free-viewing task allows us to investigate human viewing behavior under natural conditions. In this context, the majority of previous studies focused on the impact of basal image properties, such as color and luminance differences, to quantify the extent to which our fixation behavior is guided by these so-called low-level image properties. However, in most experimental studies complex images are observed only one time, whereas we are continually confronted with repeated visual impressions in everyday life. Therefore, I introduce a repeated-presentation-design that allows scrutinizing the impact of low-level image properties and the power of scene types over time. Besides these low-level factors, I also address inter-individual differences in motivation as well as emotional components as so-called high-level factors in overt attention. Previous research on visual attention has widely neglected these factors, especially in the context of real-world images. On the basis of novel study designs and by means of various analysis techniques, I show how several low- and high-level factors influence overt attention on complex scenes, how they interact, and how eye movement parameters are interrelated. In addition to that, I provide a comprehensive review of the previous literature on emotions’ and personality traits’ impacts on visual attention. On the basis of the inconsistent understanding of core concepts in the literature, I describe how behaviorally oriented studies investigate these high-level factors in visual attention, how the interplay between emotion and attention is conceptualized from a neuroscientific perspective, and I derive several conceptual and practical recommendations for future research. Finally, I outline some new ideas and venues for future research in the general discussion of the present work, for example how eye-tracking might overcome some fundamental problems of classical testing in psychological diagnostics, or how the view of embodied cognition can help us to get a better understanding of high- and low-level factors in visual attention.
7

Sensory Integration under Natural Conditions: a Theoretical, Physiological and Behavioral Approach

Onat, Selim 02 September 2011 (has links)
We can affirm to apprehend a system in its totality only when we know how it behaves under its natural operating conditions. However, in the face of the complexity of the world, science can only evolve by simplifications, which paradoxically hide a good deal of the very mechanisms we are interested in. On the other hand, scientific enterprise is very tightly related to the advances in technology and the latter inevitably influences the manner in which the scientific experiments are conducted. Due to this factor, experimental conditions which would have been impossible to bring into laboratory not more than 20 years ago, are today within our reach. This thesis investigates neuronal integrative processes by using a variety of theoretical and experimental techniques wherein the approximation of ecologically relevant conditions within the laboratory is the common denominator. The working hypothesis of this thesis is that neurons and neuronal systems, in the sensory and higher cortices, are specifically adapted, as a result of evolutionary processes, to the sensory signals most likely to be received under ecologically relevant conditions. In order to conduct the present study along this line, we first recorded movies with the help of two microcameras carried by cats exploring a natural environment. This resulted in a database of binocular natural movies that was used in our theoretical and experimental studies. In a theoretical study, we aimed to understand the principles of binocular disparity encoding in terms of spatio-temporal statistical properties of natural movies in conjunction with simple mathematical expressions governing the activity levels of simulated neurons. In an unsupervised learning scheme, we used the binocular movies as input to a neuronal network and obtained receptive fields that represent these movies optimally with respect to the temporal stability criterion. Many distinctive aspects of the binocular coding in complex cells, such as the phase and position encoding of disparity and the existence of unbalanced ocular contributions, were seen to emerge as the result of this optimization process. Therefore we conclude that the encoding of binocular disparity by complex cells can be understood in terms of an optimization process that regulates activities of neurons receiving ecologically relevant information. Next we aimed to physiologically characterize the responses of the visual cortex to ecologically relevant stimuli in its full complexity and compare these to the responses evoked by artificial, conventional laboratory stimuli. To achieve this, a state-of-the-art recording method, voltage-sensitive dye imaging was used. This method captures the spatio-temporal activity patterns within the millisecond range across large cortical portions spanning over many pinwheels and orientation columns. It is therefore very well suited to provide a faithful picture of the cortical state in its full complexity. Drifting bar stimuli evoked two major sets of components, one coding for the position and the other for the orientation of the grating. Responses to natural stimuli involved more complex dynamics, which were locked to the motion present in the natural movies. In response to drifting gratings, the cortical state was initially dominated by a strong excitatory wave. This initial spatially widespread hyper-excitatory state had a detrimental effect on feature selectivity. In contrast, natural movies only rarely induced such high activity levels and the onset of inhibition cut short a further increase in activation level. An increase of 30% of the movie contrast was estimated to be necessary in order to produce activity levels comparable to gratings. These results show that the operating regime within which the natural movies are processed differs remarkably. Moreover, it remains to be established to what extent the cortical state under artificial conditions represents a valid state to make inferences concerning operationally more relevant input. The primary visual cortex contains a dense web of neuronal connections linking distant neurons. However the flow of information within this local network is to a large extent unknown under natural stimulation conditions. To functionally characterize these long-range intra-areal interactions, we presented natural movies also locally through either one or two apertures and analyzed the effects of the distant visual stimulation on the local activity levels. The distant patch had a net facilitatory effect on the local activity levels. Furthermore, the degree of the facilitation was dependent on the congruency between the two simultaneously presented movie patches. Taken together, our results indicate that the ecologically relevant stimuli are processed within a distinct operating regime characterized by moderate levels of excitation and/or high levels of inhibition, where facilitatory cooperative interactions form the basis of integrative processes. To gather better insights into the motion locking phenomenon and test the generalizability of the local cooperative processes toward larger scale interactions, we resorted to the unequalized temporal resolution of EEG and conducted a multimodal study. Inspired from the temporal properties of our natural movies, we designed a dynamic multimodal stimulus that was either congruent or incongruent across visual and auditory modalities. In the visual areas, the dynamic stimulation unfolded neuronal oscillations with frequencies well above the frequency spectrum content of the stimuli and the strength of these oscillations was coupled to the stimuli's motion profile. Furthermore, the coupling was found to be stronger in the case where the auditory and visual streams were congruent. These results show that the motion locking, which was so far observed in cats, is a phenomenon that also exists in humans. Moreover, the presence of long-range multimodal interactions indicates that, in addition to local intra-areal mechanisms ensuring the integration of local information, the central nervous system embodies an architecture that enables also the integration of information on much larger scales spread across different modalities. Any characterization of integrative phenomena at the neuronal level needs to be supplemented by its effects at the behavioral level. We therefore tested whether we could find any evidence of integration of different sources of information at the behavioral level using natural stimuli. To this end, we presented to human subjects images of natural scenes and evaluated the effect of simultaneously played localized natural sounds on their eye movements. The behavior during multimodal conditions was well approximated by a linear combination of the behavior under unimodal conditions. This is a strong indication that both streams of information are integrated in a joint multimodal saliency map before the final motor command is produced. The results presented here validate the possibility and the utility of using natural stimuli in experimental settings. It is clear that the ecological relevance of the experimental conditions are crucial in order to elucidate complex neuronal mechanisms resulting from evolutionary processes. In the future, having better insights on the nervous system can only be possible when the complexity of our experiments will match to the complexity of the mechanisms we are interested in.
8

The effects of anxiety on visual attention for emotive stimuli in primary school children

Kelly, Lauren January 2014 (has links)
Anxiety can be advantageous in terms of survival and well-being, yet atypically high levels may be maladaptive and result in the clinical diagnosis of an anxiety disorder. Several risk factors have been implicated in the manifestation of clinical anxiety, including cognitive biases. In recent years, a plethora of research has emerged demonstrating that anxious adults exhibit biases of attention for threatening stimuli, especially that which is biologically relevant (e.g., facial expressions). Specific components of attentional bias have also been identified, namely facilitated engagement, impaired disengagement, and avoidance. However, the majority of studies have focused on the spatial domain of attention. Furthermore, the area is under-researched in children, despite research demonstrating that symptoms relating to clinical and non-clinical anxiety follow a stable course from childhood through to adolescence and adulthood. Consequently, the aim of this thesis was to investigate how anxiety affects children’s visual attention for emotive, particularly angry, faces. In order to provide a more comprehensive understanding, the current research involved examining the role of temporal and spatial attention utilising rapid serial visual presentation with the attentional blink, and the visual probe paradigm, respectively. The main hypothesis was that high state and/or trait anxiety would be associated with an attentional bias for angry, relative to positive or neutral faces in both the temporal and spatial domains. In relation to the temporal domain, key findings demonstrated that high levels of trait anxiety were associated with facilitated engagement towards both angry and neutral faces. It was further found that all children rapidly disengaged attention away from angry faces. Findings related to the processing of angry faces accorded with the main hypothesis stated in this thesis, as well as research and theory in the area. The finding that anxious children preferentially processed neutral faces in an attentional blink investigation was unexpected. This was argued to potentially reflect this stimulus type being interpreted as threatening. Key findings regarding the spatial domain were that high trait anxious children displayed an early covert bias of attention away from happy faces and a later, overt bias of attention away from angry faces. The finding that high trait anxiety was linked to an attentional bias away from happy faces in a visual probe task was also unexpected. This was argued to potentially reflect smiling faces being interpreted as signifying social dominance, thus resulting in the viewer experiencing feelings of subordination and becoming avoidant and/or submissive. To conclude, this thesis has enhanced current knowledge of attentional bias in both the temporal and spatial domains for emotive stimuli in anxious children. It has demonstrated that higher levels of trait anxiety moderate children’s allocation of attentional resources to different stimulus types, whether these are threatening, positive, or neutral. This has important implications for evaluating past research in adults and children, and for further developing theoretical models of attentional bias and anxiety. It also offers important clinical implications, since attending towards or away from specific stimuli may affect the development and maintenance of anxiety disorders. Recently, a treatment that aims to modify attentional bias in anxious individuals has begun to be developed. In light of the present findings, it may be necessary to review this treatment so that anxious children are re-trained in the specific biases of attention demonstrated here.

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