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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.
91

The Effects of Doriden on Concentrative Attention Span and Problem Solving Ability in Mice

Putnam, David G. 01 1900 (has links)
It is the purpose of this thesis to examine the effect of Doriden on problem solving. Specifically, the present study was designed as an exploratory investigation of the effects of Doriden on the maze learning ability of mice.
92

Joint Attention Interventions for Young Children with Autism Spectrum Disorders: Caregiver and Child Actions and Transactions

Vo, Abigail 21 April 2011 (has links)
Early intervention is a critical component of efforts to optimize outcomes for children with autism spectrum disorders (ASD) and their families. One promising target for early intervention is joint attention, an early developing social-cognitive competency that is foundational to many other social, communicative, and cognitive skills; and a core deficit in children with ASD. While joint attention interventions are gaining interest among researchers, many are limited by their failure to situate joint attention development within the caregiver-child relationship and to adequately examine child and caregiver outcomes and transactional processes. The purpose of this study was to examine changes in child and caregiver joint attention actions and transactions across the course of a parent-mediated joint attention intervention. The Child-Caregiver Joint Attention coding system was developed and applied to videotaped caregiver-child interaction sessions from all phases of the Joint Attention Mediated Learning intervention. Participants included five mothers and their toddler aged sons. Joint attention actions examined included gaze alternations, pointing, showing, joint attention responding, and joint attention initiating for both children and caregivers. Four of five children demonstrated increases in gaze alternations, joint attention responding, and joint attention initiating by the end of the intervention. Three caregivers demonstrated increases in gaze alternations and joint attention responding, and four displayed increases in joint attention initiating. There was no clear pattern of change across children or caregivers in pointing or showing. All participants, with the exception of one caregiver, responded to a higher percentage of opportunities for joint attention in the final intervention phase than in Baseline, suggesting that most participants became more responsive to their social partners by the end of the intervention. The findings of this study suggest that parent-mediated joint attention interventions have the potential to promote changes in both child and caregiver joint attention actions and transactional relationships. Future research should continue to examine outcomes for both children and primary caregivers and changes in child-caregiver transactions over the course of different types of joint attention interventions in order to inform intervention development and selection, and explore mechanisms for change.
93

Motion and Attention

Unknown Date (has links)
The present study examined whether differential motion could influence the spread of attention across an object. In particular, we examined whether the type of motion exhibited by an object would impact the reaction time in which a participant made a judgement on the location of a target or the accuracy of their judgment. We did not find significant effects of motion type upon reaction time. We did find that accuracy was significantly greater for validly cued targets than for invalidly cued targets. Further investigation may be needed to demonstrate the impact of motion upon the spread of attention across an object. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
94

Information encoding: importance of attention in change blindness task. / Attention in CB

January 2006 (has links)
Li Yuk Lam. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 91-97). / Abstracts in English and Chinese. / Chapter Chapter 1 : --- Introduction --- p.6 / Brief Summary in Change Blindness Studies --- p.6 / Visual Processing and Change Blindness --- p.9 / Attention and Change Blindness --- p.9 / Different Types of Memory and Change Blindness --- p.16 / General Overview of the Paper --- p.19 / Chapter Chapter 2 : --- Experiment 1 --- p.23 / Experiment 1A --- p.25 / Method --- p.27 / Participants --- p.27 / Materials & Apparatus --- p.27 / Design & Procedure --- p.28 / Result --- p.31 / Discussion --- p.33 / Experiment IB --- p.34 / Method --- p.36 / Participants --- p.36 / Materials and Apparatus --- p.36 / Design and Procedure --- p.37 / Result --- p.39 / Discussion --- p.43 / Comparing Experiment 1A and IB --- p.45 / Discussion --- p.49 / Chapter Chapter 3 : --- Experiment 2 --- p.51 / Method --- p.53 / Participants --- p.53 / Materials & Apparatus --- p.53 / Design & Procedure --- p.53 / Result --- p.54 / Discussion --- p.56 / Chapter Chapter 4: --- Experiment 3 --- p.57 / Method --- p.61 / Participants --- p.61 / Materials & Apparatus --- p.61 / Design & Procedure --- p.62 / Result --- p.63 / Discussion --- p.68 / Chapter Chapter 5 : --- Experiment 4 --- p.69 / Method --- p.72 / Participants --- p.72 / Materials & Apparatus --- p.72 / Design & Procedure --- p.72 / Result --- p.73 / Discussion --- p.78 / Chapter Chapter 6 : --- General Discussion --- p.78 / Attention and Change Blindness --- p.79 / Stability of Different Kinds of Visual Information --- p.84 / Chapter Chapter 7 : --- Conclusion --- p.88
95

Visual attention to social and non-social objects in the autism spectrum

Black, Joanne January 2015 (has links)
Autism Spectrum Disorders (ASDs) are characterised by impairments in social interaction and communication, and restricted interests or repetitive behaviours. Autism traits are theorised to lie on a continuum throughout the general population, with individuals with a clinical diagnosis at one extreme. Those with high levels of autism traits in the general population have been found to display similar characteristics to those with ASD, but to a lesser extent. Differences in visual attention to social and non-social information are thought to contribute to the characteristic behaviours in autism. Whilst social attention may be diminished in ASD, ASD may also be associated with an increase in attention towards objects that are of circumscribed interest. The present thesis investigated visual attention to social and non-social objects in participants with ASD and those from the general population with high and low autism traits, to investigate whether differences in social and non-social visual attention relate to the autism spectrum. Dot probe, peripheral cueing, and eye tracking tasks were used to explore different elements of visual attention, including orienting and disengaging. Overall, social objects captured attention more than non-social objects, revealing the high salience of social information. Participants with high levels of autism traits and a diagnosis of ASD showed reduced social attention in the dot probe and eye tracking tasks, but not the peripheral cueing experiment. Across all experiments, there was no evidence to suggest that the autism spectrum was related to attentional biases towards objects related to circumscribed interests. However, other non-social stimuli appeared to capture attention to a greater extent across the spectrum. The differences in social attention in those with higher autism traits and ASD appeared greater when more stimuli were competing for attention, suggesting reduced social attention may involve interference from non-social stimuli in the visual field. This may indicate that attention is guided more by visual properties of the stimuli than their semantic meaning in the autism spectrum.
96

Effects of alcohol on attention in alcoholics

Muller, James Julius January 1963 (has links)
Thesis (Ph.D.)--Boston University / This study is an investigation of the effects of alcohol ingestion on attention in alcoholics. Alcoholism is herein defined as alcohol ingestion, over which the individual exercises no control, in association with deterioration in marital or family relations, social status, or vocational activity for five or more years. Attention is defined as heightened accuracy in recognizing stimuli congruent with expectancies, where equally available incongruent material is less well recognized. Higher recognition of congruent than of incongruent signals is "narrow" focus of attention. Uniform accuracy in recognizing congruent and incongruent signals is "broad," or unfocused attention. Existing data indicates that relative narrowness of attention depends on the distinctiveness of stimulus qualities, and on personal capacities to develop and maintain attention-setting expectancies. Recent findings indicate alcoholics as a group may fail to narrow attention when directive qualities are lacking in the stimulus environment, and may therefore depend more on external stimulation than inner initiative for focusing attention [TRUNCATED]
97

Essays on Network Formation and Attention

Neligh, Nate Leigh January 2018 (has links)
This dissertation tackles two important developing topics in economics: network formation and the allocation of attention. First, it examine the idea that the timing of entry into the network is a crucial determinant of a node’s final centrality. We propose a model of strategic network growth which makes novel predictions about the forward-looking behaviors of players. In particular, the model predicts that agents entering the network at specific times will become central “vie for dominance”. In a laboratory experiment, we find that players do exhibit “vying for dominance” behavior, but do not always do so at the predicted critical times. A model of heterogeneous risk aversion best fits the observed deviations from initial predictions. Timing determines whether players have the opportunity to become attempt to become dominant, but individual characteristics determine whether players exploit that opportunity. This dissertation also examines models of rational inattention, in which decision-makers rationally evaluate the trade-off between the costs and the benefits of information acquisition. We provide results on recovering the implicit attention cost function by looking at the relationship between incentives and performance. We conduct laboratory experiments consisting of simple perceptual tasks with fine-grained variation in the level of potential rewards. We find that most subjects exhibit monotonicity in performance with respect to potential rewards, and there is mixed evidence on continuity and convexity of costs. We also perform a model selection exercise and find that subjects’ behavior is generally most consistent with a small but diverse subset of cost functions commonly assumed in the literature.
98

How is object-based attention modulated by the identicality between targets?. / 基于客体的注意是如何受目标子一致性调节的? / Ji yu ke ti de zhu yi shi ru he shou mu biao zi yi zhi xing diao jie de?

January 2013 (has links)
同客体效应通常被用来支持基于物体的注意分配这一理论观点,该效应已被广大研究者所证实。但是,与之同时,有些研究者报告发现与同客体效应完全相反的效应---异客体效应。因此,本文旨在探究为何这两种看似矛盾的效应会在不同的研究中出现,从而解决由这两类效应引发的冲突。研究一通过6个实验并且采用不同的刺激、任务以及研究范式来检验异客体效应的稳定性以及普遍性。研究结果表明,正如已被广泛探究和验证的同客体效应一样,异客体效应同样也是一种有效稳定并且普遍存在的效应,该效应可以在不同的实验情境下出现。这些结果激发了研究二中探讨的一系列新的问题。即,既然异客体效应也是一种有效稳定并且普遍存在的效应,而并非只是一些特定方法的产物,那为什么该效应会发生,其内在的心理机制是什么?此外,假如同客体与异客体这两种效应都是有效稳定的效应,那么这两种效应分别会在什么时候出现,以及哪些因素可以预测决定这两种效应的出现。研究二通过5个实验并且调控两个目标子之间的一致性来探究以上问题。结果发现,当两个目标子是相同的刺激(甚至当两个目标子只是在身份上一样而物理特征上不一样),异客体效应出现;而当两个目标子是不同刺激时,则同客体效应出现。此外,这些结果已经被证明并不仅仅是由于被试的反应偏差所导致的。总得来说,本次研究结果证明 1)异客体效应与同客体效应一样,也是一种有效稳定并且普遍存在的效应; 2)两目标子之间的一致性可以预测决定同客体或是异客体效应的出现。 / The same-object advantage (SOA) effect is usually cited as evidence favoring the view of object-based attention. However, the different-object advantage (DOA) effect, which appears to be the opposite of the SOA effect, has also been reported by some researchers. The present study was designed to resolve this apparent inconsistency. In Study 1, I tested the robustness and generality of the DOA effect through a series of six experiments (Experiments 1-6) by exploiting different stimuli, tasks and paradigms. The results demonstrated that, as the well-documented SOA effect, the DOA effect was also a robust effect that can emerge under numerous circumstances, rather than just the byproducts of certain methods. These findings motived the second study in which I attempted to investigate the mechanism underlie DOA effect, as well as to explore critical factors that can predict the presences of SOA and DOA effects. Specifically, with a series of another five experiments (Experiments 7-11), I manipulated the identicality between two targets and found the SOA effect when the targets were different but the DOA effect when they were identical (even when the targets just share a common identity but different physical formats). These findings have been proved not just arose from any possible response bias. Taken together, the results of the present study demonstrate that 1) the DOA effect was also a robust effect as the SOA effect, and 2) the occurrences of SOA versus DOA effects can be critically determined by the identicality between targets. / Detailed summary in vernacular field only. / Chen, Hui. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 96-103). / Abstracts also in Chinese. / Abstract --- p.II / Chinese Abstract --- p.IV / Acknowledgements --- p.V / Contents --- p.VII / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Previous studies on the SOA effect --- p.2 / Chapter 1.1.1. --- SOA effect based on divided-attention paradigm: --- p.2 / Chapter 1.1.2. --- SOA effect based on spatial-cuing paradigm --- p.5 / Chapter 1.2. --- Theories of SOA effect --- p.6 / Chapter 1.2.1 --- Sensory enhancement hypothesis --- p.7 / Chapter 1.2.2. --- Attentional shifting hypothesis --- p.9 / Chapter 1.2.3. --- Attentional prioritization hypothesis --- p.11 / Chapter 1.3. --- The factors that can affect SOA effect --- p.14 / Chapter 1.3.1. --- Cue-target stimulus onset asynchrony --- p.15 / Chapter 1.3.2. --- Object preview time --- p.16 / Chapter 1.3.3. --- Goodness of the object --- p.17 / Chapter 1.3.4. --- Spatial extent of attention --- p.18 / Chapter 1.4. --- Previous studies on the DOA effect --- p.19 / Chapter Chapter 2. --- The current study --- p.23 / Chapter 2.1. --- Aim of the present study --- p.23 / Chapter 2.2. --- Overview of the present study --- p.23 / Chapter Chapter 3. --- Study 1: The robustness and generality of the DOA effect --- p.25 / Chapter 3.1. --- Experiment 1 --- p.25 / Chapter 3.1.1. --- Method --- p.25 / Chapter 3.1.2. --- Results --- p.27 / Chapter 3.1.3. --- Discussion --- p.29 / Chapter 3.2. --- Experiment 2 --- p.30 / Chapter 3.2.1. --- Method --- p.30 / Chapter 3.2.2. --- Results --- p.31 / Chapter 3.2.3. --- Discussion --- p.33 / Chapter 3.3. --- Experiment 3 --- p.34 / Chapter 3.3.1. --- Method --- p.34 / Chapter 3.3.2. --- Results --- p.36 / Chapter 3.3.3. --- Discussion --- p.37 / Chapter 3.4. --- Experiment 4 --- p.38 / Chapter 3.4.1. --- Method --- p.39 / Chapter 3.4.2. --- Results --- p.40 / Chapter 3.4.3. --- Discussion --- p.43 / Chapter 3.5. --- Experiment 5 --- p.44 / Chapter 3.5.1. --- Method --- p.44 / Chapter 3.5.2. --- Results --- p.46 / Chapter 3.5.3. --- Discussion --- p.47 / Chapter 3.6 --- Experiment 6 --- p.48 / Chapter 3.6.1. --- Method --- p.48 / Chapter 3.6.2. --- Results --- p.51 / Chapter 3.6.3. --- Discussion --- p.53 / Chapter Chapter 4. --- Study 2: The mechanism underlie DOA effect and the factor that determine the occurrence of SOA vs. DOA effect --- p.55 / Chapter 4.1 --- Experiment 7 --- p.57 / Chapter 4.1.1. --- Method --- p.57 / Chapter 4.1.2. --- Results --- p.59 / Chapter 4.1.3. --- Discussion --- p.61 / Chapter 4.2 --- Experiment 8 --- p.61 / Chapter 4.2.1. --- Method --- p.62 / Chapter 4.2.2. --- Results --- p.63 / Chapter 4.2.3. --- Discussion --- p.64 / Chapter 4.3 --- Experiment 9 --- p.65 / Chapter 4.3.1. --- Method --- p.66 / Chapter 4.3.2. --- Results --- p.67 / Chapter 4.3.3. --- Discussion --- p.69 / Chapter 4.4 --- Experiment 10 --- p.69 / Chapter 4.4.1. --- Method --- p.70 / Chapter 4.4.2. --- Results --- p.71 / Chapter 4.4.3. --- Discussion --- p.72 / Chapter 4.5 --- Experiment 11 --- p.74 / Chapter 4.5.1. --- Method --- p.74 / Chapter 4.5.2. --- Results --- p.76 / Chapter 4.5.3. --- Discussion --- p.78 / Chapter Chapter 5. --- General discussion --- p.79 / Chapter 5.1 --- Overview of present findings --- p.79 / Chapter 5.2 --- When can SOA effect happen? --- p.81 / Chapter 5.2.1 --- The initial distribution of attention --- p.82 / Chapter 5.2.2 --- The relationship between targets and objects --- p.84 / Chapter 5.3 --- When can DOA effect happen? --- p.86 / Chapter 5.4 --- How can SOA effect happen? --- p.88 / Chapter 5.5 --- How can DOA effect happen? --- p.90 / Chapter 5.6 --- The possible relationships between SOA and DOA effects --- p.92 / Chapter 5.7 --- Limitations and future directions --- p.93 / BIBLIOGRAPHY --- p.96
99

Nonspatial inhibition of return (IOR) in attentional orienting. / CUHK electronic theses & dissertations collection

January 2009 (has links)
First, although there is some evidence suggesting IOR influences nonspatial attribute-based visual search, the effects observed have been small and inconsistent, have not followed the same time course as more standard IOR, and there is some evidence that the effect may depend on presenting a "neutral attractor" between the cue and target. In Experiments 1(1a,1b) and Experiment 2(2a), participants ii demonstrated a robust color-, and shape-based inhibitory effect that, unlike previous findings, followed a time course similar to that for location-based IOR. Moreover, the effect does not seem to require the presentation of a neural attractor. Experiment 3 and Experiment 2b demonstrated that less or no attribute-based IOR appeared if the cue and target were less salient. The results showed that if the stimuli offer featural differences that are salient enough, the perceptual system uses them to encode the displays, and IOR can be applied to those features. / Inhibition of return (IOR) has been reported when a target is preceded by an irrelevant stimulus (cue) at the same location: Target detection is slowed, relative to uncued locations. It is suggested that IOR is a general phenomenon that helps to provide a broad sampling of stimuli in the environment. In recent years, however, the generality of the IOR phenomenon has been questioned. Although there is considerable research demonstrating inhibition of cued locations, and a mountain of evidence for inhibition of cued objects, inhibition of cued nonspatial attributes, like color, shape and orientation, has rarely been explicitly demonstrated. Using a paradigm that has shown robust location-based IOR when relatively richer displays are presented, the present thesis addresses three noticeable gaps in the IOR literature relating to nonspatial feature visual search. / Second, the nonspatial-based IOR effect does not seem to be independent of location, as it only occurs when cue and target share not only features, but location. The results suggest that attentional selection can be applied to stimulus properties such as color, shape, and orientation, but that the attentional operations are specified in location-based coordinates. Given location-based IOR appeared in all experiments, repetition of nonspatial features may reflect an additional phenomenon. When the cue and the target do not share location, they can not be the same object, indicating featural IOR is rather object based. / Third, in Experiment 4, 5 and 6, when attribute discrimination tasks were required, the attribute-based IOR was gone. So far, there have been a limited number of studies examing the attribute-based discrimination research, and the results of them are mixed. Our results clearly indicated that the attribute-based inhibitory effect does not generalize to higher mental demanding tasks. We suggested that this type of cuing effects can be considered as different manifestations of attentional capture on non-spatial attributes processing, that is, under attribute-based higher demanding tasks observers allocate attestation to locations, rather than to attributes; hence IOR is predominantly location-based. / To conclude, these findings shed considerable light on IOR: nonspaital attribute-based IOR can be demonstrated under certain conditions, with rich displays, and with enough stimulus salience. Critically, the effect of inhibition directed to an attribute is tied to the location of the prior stimulus. The effect also depends on the difficulty of the target processing (simple detection task vs. discrimination task). / Hu, Kesong. / Adviser: Agnes S.Chan. / Source: Dissertation Abstracts International, Volume: 72-11, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 108-122). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
100

Dynamics Of Cognitive Control And Midline Theta Activity Across Multiple Timescales

January 2016 (has links)
Humans frequently encounter cognitive conflict situations, such as the need to ignore distractions or make a decision with multiple options. Cognitive control over attention and behavior in conflict situations is a basic executive functioning skill vital for goal-oriented behaviors. Musicians spend many hours exercising cognitive control while ignoring distractions, focusing on specific sounds, and avoiding incorrect movements. Therefore, musicians are a useful population to examine the effects of long-term experience on cognitive control. The current study used independent component analysis, time-frequency analysis, and ERP analysis on electrophysiological data to identify neocortical activity and timescales of cognitive control during an auditory Simon Task. Musicians showed no cognitive control advantage over non-musicians. Consistent with previous research, we found short-term compatibility sequence effects as well as longer-term effects of base rate (proportion of compatible trials) in response time Simon effect data. Sequence effects and a base rate x compatibility interaction also emerged for some ERP and ERSP components, including frontal theta in the ERSPs. We then used predictive models to test whether changes in the Simon effect across base rates were due to changing numbers of each sequence type that necessarily accompany base rate manipulations. Results indicate that sequence effects account for 17% of the reaction time cognitive control shift associated with proportion compatible manipulations. The base rate manipulation affected behavior and neural correlates above and beyond sequence effects. / Lisa Chinn

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