<p> Boundary extension is a perceptual phenomenon in which people remember more of a scene than they actually saw. This effect is very robust, found in subjects of all ages, and observed as rapidly as 1/20th of a second after scene onset. Due to several factors, including the rapid onset, boundary extension is thought to be an automatic process. However, some studies have indicated that attentional factors may influence the effect. This study examined the idea that differences in attention may alter the degree of boundary extension. Specifically, the current study investigated the automaticity of boundary extension by altering the attentional resources allocated to an image. This was manipulated in two ways. First, the location of the objects in the scene were placed either centrally or peripherally. Second, the categorical distinctiveness of the objects in the scene was manipulated such that half of the images contained a single distinctive object while the other half contained none. Including distinctive objects in the picture plane should entice participants to more deeply process the images, thus attenuate boundary extension. Individual differences in need for cognition and field dependence/independence were also considered. These additional scales allowed for the examination of individual differences in information processing styles in relation to the boundary extension error. Results indicate the relationship between these factors is complex, but that in general, increased attention reduces the degree of reported boundary extension. </p>

The purpose of this project was to investigate 8-month-old infants' representation and tracking of objects in occlusion events. Recent research has shown that young infants are able to reason about various aspects of physical objects' behavior. This project further explores this ability and delineates some limits to it. Specifically, the first set of studies (1A-1F) investigated whether infants' apply spatiotemporal continuity to collections of objects as they do to single objects. Because to adults a collection can be viewed as multiple objects as well as a non-object individual, infants' tracking of a collection may thus inform us not only about their representation of objects but also about their representation of non-object entities. The second set of studies (2A and 2B) focused on infants' detection of spatiotemporal discontinuity in object behavior in different situations: The disappearance versus appearance situation. These two sets of studies revealed two limitations in infants' application of spatiotemporal continuity: While 8-month-old infants are able to detect the discontinuous disappearance of single objects, they (a) do not readily detect the discontinuous disappearance of a collection but succeed only in certain circumstances, and (b) do not detect the discontinuous appearance of single objects. These limitations have important implications for infants' knowledge of and tracking systems for objects. Finally, some general issues arising from the current project are discussed.

<p> This dissertation couples the growing corpus of human subjects and behavioral research in information security with large-scale data and robust quantitative methods. Linking human subject experimentation with theoretical models enables the information security community to reason more effectively about the system-wide effects of user behavior. I examine how users interact with the digital environment, how those interactions affect decision-making, and how aggregate decision-making affects system-wide vulnerabilities. This interdisciplinary challenge requires a combination of techniques from cognitive neuroscience, social network analysis, human-subjects research, dynamical systems, network theory, and agent-based models. </p><p> In the first section, eye-tracking data demonstrates the relationships between expertise and online perceptual awareness of security cues. Expertise is shown to be only a small factor in attention to security cues, and task-type proves to be much larger indicator of attention, with tasks requiring the use of personal accounts driving attention to cues. This section uses Bayesian ANOVA to evaluate users' perceptual awareness of security cues as they complete common online tasks, as it relates to user sophistication and task type. </p><p> The second section uses a theoretical epidemiological model of malware spread to investigate factors that might mitigate the prevalence of malware in a coupled, two-population model. This both demonstrates that cost is the largest factor for affecting malware prevalence, outside of malware infection rates, and identifies appropriate strategies for system-wide botnet mitigation. </p><p> The final section utilizes an agent-based model of mobile application adoption combined with social network data and mobile marketplace policy. The result is an examination of the dynamic effects of user and market behavior on the spread of mobile malware and the second order effects, such as privacy loss, due to that spread. This model reveals that well-regulated markets are effective at limiting malware spread, but user behavior grows in importance as markets become less restricted. </p><p> Each study examines ways in which users interact with their technology, the aggregate effects of those behaviors, and identifies possible inflection points to change system-wide behaviors. This dissertation integrates empirical behavioral studies to develop a better understanding of digital behavior, thus enabling a more holistic approach to information security.</p>

<p> This study examined cultural differences in children's collaborative processes and explored the relationship between these collaborative processes and the children's collaboration in household work. 30 6- to 10-year-old sibling pairs from Mexican-heritage and middle-class European-heritage backgrounds participated in the study. Home visits were conducted using a planning task where dyads planned five grocery-shopping trips using a model store, first creating individual plans and then working together to create a combined plan. After participants completed their individual plans, the research assistant asked them to work together and help each other to make the shortest route to pick up all the items on their shopping list. Using 10-second segments, data were coded in four main categories; fluid ensemble, coming to agreement, one child leads activity, or dividing separate roles (which had several subcategories). Mexican Indigenous-heritage siblings collaborated as an ensemble in a higher proportion of segments than middle-class European-heritage siblings, who spent more segments dividing roles. Specifically, when European-heritage pairs were dividing roles they spent a higher proportion of segments being <i>bossy </i> to their sibling with the sibling <i>implementing</i> their plan, and ignoring their sibling while working on the plan. There was a positive relationship between siblings' collaboration at home and collaboration in the planning task. Siblings who were reported to collaborate with initiative in household work, based on mothers' reports, were more likely to collaborate as fluid ensemble with their sibling in the planning task. In contrast, children that were reported to do household work only when adults managed their chores were more likely to collaborate by being bossy to their sibling or by ignoring their sibling while working on the plan. Findings may help us better understand how cultural practices contribute to children's tendencies to collaborate with others in different contexts, including in the classroom setting where collaboration might be discouraged or managed by adults.</p>

In this thesis, I shall explore the theoretical and empirical expositions regarding the causal mechanisms of cognitive growth. I shall do this in order to determine if biological epistemic theories of cognitive systems can be justified. It will be necessary in this thesis for me to adopt a multidisciplinary stance from Philosophy and Psychology. It will try to investigate from these two perspectives what it means to be a cognitive creature. However, I shall argue, if taken singularly, each standpoint fails to provide an adequate account of cognition that is necessarily based on adaptive, evolutionary constructs. During this thesis I will primarily focus on the major arguments in Philosophy that show a tight coupling between language, cognition and rationality. More specifically I will examine in detail Donald Davidson’s holistic account of what it is to be a rational, cognitive creature. I will show in the thesis, through comparative experimental evidence, that the causal mechanisms of cognitive growth, and thus thought may not be language. Consequently, Philosophical arguments that are based on tight relationships of thought and language will not be able to deliver a true account of cognition. I will demonstrate that Davidson’s philosophy has suffered from not being able to ground his philosophical perspectives on the relationship of language, cognition and rationality within an empirical programme and consequently it makes fundamental errors. Davidson’s account does not take on board the recent (and not so recent) empirical based work on primates which show the possible mechanisms of cognitive growth, which are independent of language. Similarly, I will also show that Psychology, which does provide us with the means to deliver an empirical account of cognition, due to its history based on Behaviourism, does not have the right causal mechanisms nor language to talk about the nature of complex cognition. I will show how Associationistic Psychology mischaracterises what it is to be cognitive and consequently, like philosophy, cannot deliver an accurate ontology of cognition. I intend in this thesis to provide a bridge between the two schools by adopting a comparative psychological approach. By using this comparative perspective, a more accurate theory of cognition may be possible and one that is not contaminated by language or any other cultural symbolic systems. I aim by the end of the thesis to be in a position which will hopefully allow modification of Davidson’s condition on possessing beliefs, a creature must have beliefs about beliefs. This modification will be based on an evolutionary account of what may or may not eventually turn out to be the precursors of higher cognitive states.

<p> MBCT has been successful in preventing depressive relapse. However, its efficacy has not been studied in non-mental health settings for stress, affect, and level of mindfulness. In this study, participants were selected on a volunteer basis after enrolling in an 8-week Mindfulness-Based Cognitive Therapy (MBCT) group at a health and wellness center. Prior to beginning the group, participants completed the Perceived Stress Scale (PSS), Positive/Negative Affect Schedule (PANAS) and the Mindful Attention Awareness Scale (MAAS). Participants completed the PSS, PANAS, and MAAS after week four, and at the completion of the eight-week course. Twenty-two participants were included in the study. Results were computed with a one-way repeated measures ANOVA. Post hoc pairwise comparisons or paired-samples t-tests, where appropriate, were computed to examine the specificity of changes over time. Descriptive data was gathered including demographic data and homework compliance. The following two follow-up questions were included for further descriptive data: 1) On a scale of 1-10 (1 = not at all important, 10 =extremely important), how important has this program been for you? 2) Please say why you gave it that rating. Results revealed decreases in perceived stress, increased positive affect, decreased negative affect, and increased overall level of mindfulness by week eight. Qualitative data supported the empirical data. This data suggests MBCT may serve as a cost effective method for managing stress and providing useful skills in the daily lives of individuals in non-clinical and/or community populations.</p>

<p> Prior research has shown that people perceive items in a larger font size as being more memorable than items in a smaller font size. This perception leads to higher judgments of learning (JOLs; i.e., confidence ratings regarding the likelihood of recalling an item) for larger font size items than smaller font size items. Yet other research has shown that people recalled more when the information was presented in a smaller font than when it was presented in a larger font size. The present study examined if there are boundary conditions of font sizes affecting JOLs and actual recall performance. As we expected, the results show that JOLs increased as a function of the size category. The results also show that font size impacted recall performance such that items in the Smallest size category were recalled at a higher rate than items in the other three font size categories.</p>

<p> The neural substrate of interactions of working memory (WM) with socio-emotional processing is poorly understood in schizophrenia. This study builds on published papers using a delayed match to sample design to study the interaction of WM load with type of distracter (socially relevant faces vs. socially irrelevant geometric designs [FvG]) presented briefly during the WM maintenance period. Based on previously published findings, we hypothesize: (1) The FvG difference in brain activity in the dorsolateral prefrontal cortex (DLPFC) in the task maintenance period will be largest at the highest WM load. (2) Among schizophrenia/ schizoaffective patients and healthy controls the magnitude of the face vs. geometric design (FvG) contrast in brain activity in the amygdala during the task maintenance period will follow a quadratic pattern across WM load when averaged over face type. (3) Among schizophrenia patients, the magnitude of the FvG contrast in brain activity in the amygdala and DLPFC at the greatest WM load will be correlated with negative symptoms. </p><p> Individuals between the ages of 18-55 diagnosed with schizophrenia/schizoaffective disorder (N = 12) and non-psychiatric controls (N = 20) matched with the patients on age, gender, paternal education and paternal socioeconomic status underwent structural and functional magnetic resonance imaging (fMRI). To assess the effect of implicit socioemotional modulation on brain activity during WM, the effect of facial distraction on brain activation was assessed for WM of pseudowords at three syllable loads (1, 2, and 3) across several face valence types and contrasted with the effect of a geometric distracter. </p><p> Results: Although patients performed significantly above chance, they were less accurate than controls with no difference in response latency. When the FvG contrast was tested for response latency, we observed a significant quadratic effect of WM load in healthy controls but a linear effect among patients. Similar patterns were found for response accuracy but were not statistically significant. With regard to neural activity, we found a significant bilateral linear trend of percent signal change on WM load for the FvG contrast in the DLPFC. among controls, with brain activation to faces greater than activation to designs only at the highest WM load. In the amygdala we observed a significant bilateral quadratic effect of percent signal change on WM load for the FvG contrast in the control group. We observed a significant difference in neural activation patterns in patients compared to controls in the DLPFC and the amygdala. Specifically, in patients, we observed a quadratic instead of a linear trend in the DLPFC but only in the right hemisphere. In the amygdala, the patients displayed a quadratic trend also only in the right hemisphere. In neither controls nor patients did individual differences in the quadratic effect of brain activity in the amygdala correlate with the quadratic effect in response time or accuracy. Although the correlation between the magnitude of the quadratic trend in the right amygdala at the highest WM load with general psychopathology was moderately large in patients, neither this effect nor any other brain activation effects were significantly correlated with psychopathology. </p><p> Confirming hypothesis one, controls showed the largest difference in brain activity of the FvG contrast in the DLPFC during the maintenance period at the highest WM load. However, in patients we saw significantly decreased percent signal change in DLPFC at the highest WM load on the FvG contrast in the maintenance period. For hypothesis two we observed a quadratic pattern of WM load on the FvG contrast in the maintenance period for both controls and patients, although this effect was only present in the right hemisphere of patients. Furthermore, contrary to hypothesis 3 we did not observe significant correlations between symptom severity and the magnitude of the FvG contrast in brain activity in the amygdala and DLPFC at the greatest WM load. These results suggest a separate process of social-discrimination is taking place in controls. However, this process appears to be impaired in individuals with schizophrenia. This disruption may be due to poor integration of different brain areas and interhemispheric communication. (Abstract shortened by ProQuest.) </p>

<p> The current study investigated the effectiveness of using a brief mindfulness intervention for reducing test anxiety with college students, with the related goals of increasing level of mindfulness and increasing performance on a word list recall task. The effectiveness of incorporating an environmental cue, meant to act as a reminder for participants to engage in mindfulness, was also explored. Sixty-four college students were assigned to one of four groups: each group differed according to the presence or absence of the mindfulness training and environmental cue. Participants receiving mindfulness training could choose to participate in up to four 30-minute mindfulness training sessions over a two-week period. Each participant was assessed for level of test anxiety, level of mindfulness, and number of correct words recalled from a word list recall task both before and after the mindfulness training. Difference scores revealed no significant main effects or interactions related to the availability of mindfulness training or the presence of an environmental cue. However, both groups that received mindfulness training saw non-significant increases in level of mindfulness while decreases in mindfulness were seen for the groups that did not receive training. Exploratory analyses in regards to relationships found for both pre-test and post-test measures revealed significant correlations, such that as test anxiety scores decreased, mindfulness scores increased. Other interesting relationships included a positive correlation between test anxiety and the mindfulness Observing subscale, such that higher levels of test anxiety are associated with a student&rsquo;s increased ability to notice their inner experiences, and a negative correlation between the test anxiety Emotionality subscale and the mindfulness Nonjudging subscale, such that decreased autonomic responses, are associated with a student&rsquo;s increased ability to not judge those inner experiences. Implications for future research and limitations of the current study are discussed.</p>

<p> The thesis that perceptual experience is transparent has received considerable air-time in contemporary philosophy of mind and perception. Debate over its truth-value has reached an impasse. I diagnose this mired debate, and pursue a reformulation of the &ldquo;transparency thesis&rdquo; such that it can be more readily evaluated form the perspective of perceptual psychology and related subdisciplines. I argue that the empirical methods characteristic of these disciplines are important for evaluating the transparency thesis. Both historical and contemporary empirical results but substantial pressure on the transparency thesis.</p>