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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.
261

Extending the JD-R approach to predicting work/study engagement and creative performance : evidences from Chinese employees and students

WU, Mengyuan 16 September 2015 (has links)
Although innovation and creativity play an increasingly important role in helping organizations survive in today’s highly competitive environment, less is known about the antecedents and mechanisms of creative performance in the Chinese context. To bridge the gap of knowledge, this thesis adopted and extended Bakker (2011)’s Job Demands-Resources model (JD-R model) to exploring four antecedents of creative performance, namely, creative requirement (job demand), creative self-efficacy (personal resource), perceived support for creativity (job resource), and work/study engagement. It was hypothesized that engagement would mediate the positive effect of creative self-efficacy, perceived support for creativity and creative requirement on creative performance. Creative requirement would moderate the effect of creative self-efficacy, perceived support for creativity on engagement. Self-reported questionnaires were distributed to Office staff (n=154) and supermarket staff (n=158) from Mainland China. Undergraduates (N=194) were recruited from a university in Hong Kong and were asked to complete a self-reported questionnaire that included both subjective and objective tests for creativity performance. Hierarchical linear regression analyses with Bootstrapping procedures were conducted separately to test the proposed hypothesized model among the three participant groups. It was found that the hypothesized model was partially supported across all the samples. Also, different mediation mechanisms of engagement were found between employee and student samples. Engagement was found to partially mediate the positive effect of perceived support for creativity on (both subjective and objective) creative performance among three samples; yet it only partially mediated the positive effect of creative self-efficacy on employees’ creative performance. In addition, only creative self-efficacy was found to be a significant predictor of (both subjective and objective) creative performance across all three samples. Also, no moderation effects were supported. Nevertheless, the main contributions of this study to the existing creativeperformance literature are mainly twofold: (a) extending the JD-R model to incorporate creativity and (b) generalizing the JD-R model to the Chinese context. Finally, recommendations for promoting employees and undergraduates’ creative performance are discussed in the thesis.
262

Examining the generation effects on job-hopping intention by applying the Theory of Planned Behavior (TPB)

YUEN, Sze Hang 04 October 2016 (has links)
Job hopping is about people changing jobs frequently. This concept is slightly different from normal turnover in terms of employees staying in the present company for a short period of time only before they move on to the next job. While there appears to be an increased level of acceptance of job hopping, the phenomenon has also been associated with different problems faced by organizations, such as retaining experienced and trained employees. Past research has been directed to examining the roles of various social (e.g., perceived job availability) and psychological (e.g., job satisfaction, turnover culture, values and attitudes) factors in job hopping behavior. One interesting line of these researches focuses on job hopping among the younger generation (i.e., the Millennials) which is suggested to be frequent job hoppers compared to the previous generations, and this observed generational difference in job hopping is due to the poorer work attitudes (e.g., being disloyal and valuing much on extrinsic rewards) held by young people. However, a research conducted in the U.S. (Twenge, 2010) showed that younger workers are actually similar to the older generation in the way that they are also willing to stay longer in the companies instead of hopping jobs if they are satisfied with their jobs. In this research, the job hopping phenomenon of Chinese workers in the Hong Kong context was examined. A qualitative study (Study 1) was conducted with 30 young, full-time Hong Kong Chinese employees from different industries to examine their conceptions and perceptions of job hopping. Results showed that job hopping is considered different from “usual turnover” in terms of its detrimental effects to one‟s record on the curriculum vitae (CV). Most interviewees preferred not to “job hop” unless they have an especially attractive alternative offer. Bad track record on the CV resulted from job hopping is something to be avoided by most interviewees. Based on part of the findings in Study 1, a quantitative survey research (Study 2) was conducted to further investigate the purported generational differences (Generations X and Y) in job hopping intention by using the Theory of Planned Behavior framework (Ajzen, 1991). Results showed that there were no differences in attitudes towards job hopping and subjective norms, but there were significant differences in perceived control and job hopping intention between Gen X and Y. Regardless of generational differences, the TPB predictors (i.e., attitudes, subjective norms and perceived control) accounted for additional variances in explaining job hopping intention when controlling for age, education level, average tenure and job satisfaction. Implication of the findings and future research directions are also discussed.
263

Using dynamic neural fields to understand the development of metric representations in typically developing and at-risk infant populations

Perone, Sammy 01 December 2010 (has links)
During the past half-century, the experimental use of looking measures have led to many new discoveries about the origins of cognition. Across the first year, infants' looking changes in predictable ways, they form memories more quickly, and they begin to discriminate between subtly different stimuli. However, a rich understanding of the link between looking and cognitive dynamics has yet to be achieved. This was the overarching goal of this thesis. I developed a new Dynamic Field Theory of infant looking and memory and formally implemented this theory in a Dynamic Neural Field model. In Experiment 1, I tested and confirmed a prediction of the model with 10-month-old infants. The prediction was that robust memory can induce both a familiarity and novelty bias depending on the metric similarity of the familiar and novel items at which infants look. This prediction is a radical one because all existing theories posit that familiarity biases arise from weak memory. One central innovation of the DNF model is that it captures developmental change in the rate at which memories are formed and discrimination within the same system and from the same developmental mechanism. With a validated theory in hand, in Experiment 2 I tested this theoretical assumption. In particular, I measured the looking dynamics and discrimination performance of 5-, 7-, and 10-month-old infants. The results showed that infants' exhibited an increased ability to discriminate between dissimilar familiar and novel items between 5 and 7 months of age. The results also showed that three well-known looking indices of memory formation also generally change between 5 and 7 months of age. Additionally, individual differences in these looking indices were predictive of infants' discrimination performance. These findings indicate that, indeed, looking and discrimination change together, and are linked within individuals, over development. In Experiment 3 I tested developmental change in the discrimination abilities of at-risk infants. Previous studies have shown that the looking dynamics and recognition performance of at-risk infants is delayed but, critically, follows the same developmental trajectory as typically developing infants. Consistent with these previous studies, the looking dynamics of at-risk infants did change in predictable ways over development. However, their discrimination performance did not - young at-risk infants, unlike young typically developing infants or older at-risk infants, discriminated between dissimilar familiar and novel items.
264

Gender stereotypes and academic performance : the influence of salient role models on stereotype validation

Thiem, Kelsey 01 December 2016 (has links)
People commonly seek out role models when they want to achieve their goals because role models help people believe that success is possible and demonstrate how to achieve it. Because seeking out role models is a common occurrence, a great deal of research has been devoted to understanding the effects that they can have on those who look up to them. One effect that has not been previously examined is the extent to which role models can affect people’s certainty in their previous performance perceptions. Evaluative certainty is often increased for people when their performance perceptions are confirmed by the presence of a congruent stereotype: a phenomenon known as stereotype validation. Stereotype validation has been shown to effect women within stereotypically male domains. Importantly, higher evaluative certainty predicts negative downstream outcomes for these women, including lower beliefs in their math ability and reduced expectations for a future math performance. The goal of the current research was to investigate whether the salience of female role models reduces or enhances women’s evaluative certainty following stereotype validation. Four studies reveal partial support for the certainty reduction hypothesis. Stereotype-validated women are less certain of their poor performance perceptions when they are exposed to female role models.
265

The effects of caloric education, trial-by-trial feedback and their interaction on college-aged women’s abilities to estimate caloric content

Rizk, Marian Tewfik 01 August 2018 (has links)
Many people track the caloric content of food, given its relevance to weight loss, gain, or maintenance. Thus, better understanding the psychological underpinnings of caloric content estimation for unhealthy foods is of significant psychological and public health interest. This study investigated whether college-aged women could be trained to estimate the caloric content of unhealthy foods more accurately via exposure to caloric content education, trial-by-trial feedback, and their combination. Two hundred and thirty-eight college-aged women estimated the caloric content of 84 photographed foods and completed three transfer tasks. Prior to the first task, women were randomly assigned to one of four groups: Education and Feedback; Education only; Feedback only; or Neither Education nor Feedback. Following the first estimation task, participants estimated the caloric content of 24 novel photographed foods without feedback. Second, participants self-served specified caloric amounts of six real foods. Finally, participants were invited to consume as much as they would like of an unhealthy food in a five-minute period. Mixed-effects modeling estimated three aspects of the quadratic function linking true and judged caloric content: threshold (average perceived caloric content), linear sensitivity, and change in sensitivity as caloric content increases. On average, college-aged women underestimated caloric content, demonstrated substantial linear sensitivity to caloric content, and did not show reduced sensitivity as caloric content increased. Trial-by-trial Feedback, but not Caloric Education, reduced bias in caloric estimation and enhanced sensitivity to caloric content on the first two tasks. There were no effects of Feedback, Education, the interaction between Feedback and Education, BMI, or hunger on the distal transfer tasks. Overall, college-aged women showed biased but sensitive judgments of the caloric content of unhealthy food presented in images. Initial evidence suggests trial-by-trial feedback may be an efficacious strategy to enhance the accuracy of caloric content estimation, at least when viewing static images of foods.
266

A comprehensive analysis of prefrontal structural and functional changes following prolonged stress and glucocorticoid exposure in the rat

Anderson, Rachel Marie 01 May 2018 (has links)
The hypothalamo-pituitary-adrenal (HPA) axis plays a central role in promoting adaptations to acute stress, while over activity of this system may be involved in adverse effects on physiology and behavior. Glucocorticoids, the end-products of HPA axis activation, are key mediators in adaptive and maladaptive effects following acute and chronic stress. Previous research has focused on how chronic stress and elevated glucocorticoid exposure influences hippocampal structure and functioning in the rat. The prefrontal cortex, a brain region important for executive function, is involved in inhibiting the stress response but has also been shown to be affected by repeated stress exposure. The current set of experiments were designed to get a fuller picture of how chronic stress and elevated glucocorticoids impact prefrontal structure and function in the rat. Chapter 2 investigates how differences in basal functioning on the HPA axis impact prefrontal structure and functioning. Aging has been shown to be accompanied by disruptions in circadian functioning, so aged and young animals were investigated for basal adrenocortical activity. Individual differences were found in both young and aged groups, and animals were partitioned into high or low HPA activity. Aged animals with high glucocorticoid (CORT) secretion showed significant dendritic spine loss in prefrontal neurons, when compared to aged animals with low CORT secretion and young animals. Using a delayed alternation task using a T maze, a prefrontal dependent task, we showed that aged animals with high CORT secretion show significant working memory impairments compared to all groups. Chapter 3 investigates the role that glucocorticoids play in the restructuring of prefrontal structure following chronic stress. As previous work has shown that chronic stress leads to regressive alterations in dendritic spines in pyramidal neurons in the medial prefrontal cortex (mPFC), this study examined the capacity of sustained increases in circulating CORT alone to alter spine density and morphology in this region. A subset of rats were implanted with subcutaneous CORT pellets to provide continuous exposure to levels approximating the circadian mean or peak for 1, 2, or 3 weeks. Pyramidal neurons in the prelimbic area of mPFC were selected for intracellular dye filling followed by high resolution three-dimensional imaging and analysis of dendritic arborization and spine morphometry. Two or more weeks of peak CORT exposure resulted in apical dendritic retraction and dendritic spine loss, with thin spine subtypes showing the greatest degree of attrition. Finally, these alterations persisted following a 3-week washout period suggesting prolonged disruptions in HPA activity may be sufficient to induce enduring regressive structural alterations. As the majority of studies investigating the stress response have focused on male rodents, Chapter 4 investigated sex differences in prefrontal structure and function following chronic stress, and CORT exposure in male and female rats. Adult male and female rats were exposed to two weeks of chronic variable stress (CVS) and then either tested on the delayed alternation task of the T-maze or perfused for dendritic spine analyses. Both males and females showed significant impairments on the working memory task following CVS exposure compared to non-stressed animals. CVS also resulted in significant spine loss in mPFC neurons in both males and females. As chapter 2 focused on the effects of sustained CORT exposure on structural reorganization of mPFC, female animals were implanted with subcutaneous CORT pellets and analyzed for mPFC structural alterations. Females were found to show similar effects as males in that they demonstrate decreased spine density on mPFC pyramidal neurons following 2-weeks of sustained high CORT exposure. Finally, in an attempt to generalize chronic stress effects on PFC, males and females were exposed to a repeated stress paradigm and analyzed for dendritic spine changes in PFC. Both males and females exposed to 3 weeks of repeated restraint show significant spine loss compared to non-stressed animals. These results show that chronic stress and subsequent glucocorticoid exposure significantly alter PFC structure and function in both male and female rats. These data enhance our understanding of how both stress and CORT specifically alter dendritic spine density and morphology and how this may lead to changes in prefrontal function.
267

Inflammatory processes and depressive-like behavior in a syngeneic model of ovarian cancer

Lamkin, Donald Michael 01 July 2010 (has links)
Considerable data demonstrate a high prevalence of depression symptoms in patients with cancer, with some studies showing the prevalence for major depressive disorder (MDD) to be as high as 50%. Because depression researchers have found that a significant relationship exists between depression symptoms and indices of systemic inflammation and because several cancer types exploit the mechanisms of the body's inflammatory response to aid in their own progression, it was hypothesized that tumor in the body could be a cause of depression symptoms in cancer patients. Examination of this question was conducted using an immunocompetent mouse model of ovarian cancer and several measures of depressive-like and sickness behavior. Initial investigation of the model (Chapter 2) involved a series of pilot experiments that addressed methodology and demonstrated that ID8 murine ovarian carcinoma was capable of inducing elevated levels of systemic IL-6 and depressive-like behavior, specifically anhedonia as measured by a decrease in sucrose solution. In Chapter 3, a larger experiment (Experiment 1) was conducted that examined the effect of ovarian tumor on sucrose intake, food intake, body weight, locomotion, and rotarod performance. Results in the study indicated that sucrose-measured anhedonia in the model was not confounded by anorexia because tumor-bearing mice and control mice exhibited no significant difference in appetite. In Chapter 4, a second experimental factor, social housing, was added alongside tumor condition, and a second measure of depressive-like behavior, tail suspension test (TST) immobility, was added to measures from the previous experiment. The results of this second large experiment (Experiment 2) demonstrated that ovarian tumor had no significant effect on TST immobility, even though it did cause mice to exhibit less motor activity in the home cage. Housing condition did affect TST immobility. Mice that were individually-housed exhibited significantly more TST immobility than group-housed mice. Also, individually-housed mice exhibited less sucrose intake than group-housed mice. This gave rise to a significant interaction in sucrose preference among the four experimental groups where individually-housed tumor-bearing mice showed less sucrose preference than the other groups. In Chapter 5, systemic proinflammatory and antiinflammatory cytokines from both Experiment 1 and Experiment 2 were examined. Results indicated that both proinflammatory and antiinflammatory cytokines were significantly higher in tumor-bearing mice than in control mice, and these effects were largest for interleukin-6 (IL-6) and IL-10. Among tumor-bearing mice, significant correlations between IL-1β, IL-6, tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF- β) and locomotion were noted, but there was no significant correlation between cytokines and anhedonia. No significant effect of housing condition on cytokines was found. In Chapter 6, principal findings of the project are summarized and discussed with a focus on anhedonia and psychomotor slowing in MDD. Current evidence suggests that dopaminergic and glutamatergic systems in the brain may underlie anhedonic and psychomotor features in inflammation-induced depression. Thus, future investigation of the mediators between ovarian tumor and these depressive-like behaviors in the model may benefit from targeting these specific neural mechanisms.
268

Flexible recalibration of perception and action in children and adults

Ziemer, Christine Julia 01 July 2012 (has links)
We conducted eight experiments to examine how manipulating perception vs. action during walking affects perception-action recalibration in real and imagined blindfolded walking tasks. Participants first performed a distance estimation task (pretest), and then walked through an immersive virtual environment on a treadmill for 10 minutes. Participants then repeated the distance estimation task (posttest), the results of which were compared to their pretest performance. In Experiments 1a, 2a and 3a, participants walked at a normal speed during recalibration, but the rate of visual motion was either twice as fast or half as fast as the participants' walking speed. In Experiments 1b and 2b we tested 12-year-old children in the same recalibration task as 1a and 2a. In Experiments 1c, 2c, and 3b, the rate of visual motion was kept constant, but participants walked at either faster or a slower speed. During pre- and posttest, we used either a blindfolded walking distance estimation task or an imagined walking distance estimation task. Additionally, participants performed the pretest and posttest distance estimation tasks in either the real environment or in the virtual environment. With blindfolded walking as the distance estimation task for pre- and posttest, we found a recalibration effect when either the rate of visual motion or the walking speed was manipulated during the recalibration phase. With imagined walking as the distance estimation task, we found a recalibration effect when the rate of visual motion was manipulated but not when the walking speed was manipulated in both the real environment and the virtual environment. Neither blindfolded walking nor imagined walking yielded significant results when 12-year-old children were tested. Discussion focuses on how spatial updating processes operate on perception and action and on representation and action.
269

Stigma management through a threat-specific lens: when do targets anticipate and seek to manage the prejudice they face?

Lassetter, Bethany 01 May 2018 (has links)
When do targets of stigma seek to manage the prejudice they face? Recent work shows that stigmatized targets anticipate that others view their group as posing specific threats, and as a result, prioritize threat-mitigating strategies when motivated to convey a positive impression (e.g., Black men prioritize smiling to reduce physical safety threat; Neel, Neufeld, & Neuberg, 2013). I predicted that stigmatized targets use these strategies selectively: First, with people vulnerable to the threat the target is stereotyped to pose, and second, in environments that make the target’s threat salient. Black and White male participants read about a hypothetical interaction with a stranger and then ranked self-presentational strategies in order of importance for making a good impression. Study 1 showed that environmental threat and partner vulnerability did not influence rank of smiling; however, after being made aware of stereotypes people hold of African Americans in general (Study 2), Black men trended toward prioritizing smiling more in a threatening (compared to a non-threatening) environment or with a vulnerable (compared to a non-vulnerable) partner. Although further work is needed to replicate this effect before drawing concrete conclusions, this finding speaks to targets strategically employing threat-reducing behaviors with specific perceivers and in certain environments.
270

Drinking on a Work Night: A Comparison of Day and Person-Level Associations with Workplace Outcomes

Shepherd, Brittnie Renae 06 August 2019 (has links)
Alcohol use and misuse is costly for U.S. employers, primarily due to health care expenses and lost work productivity. Despite high costs for organizations, employee alcohol use is understudied within the organizational literature. The scant research conducted largely utilized cross-sectional designs examining differences across individuals, despite prevailing theoretical frameworks describing primarily within-person processes. This study examined the simultaneous within-person and between-person relationships between employee alcohol use and work and well-being outcomes. The separation and comparison of within-person and between-person effects is essential for the evaluation of key theoretical frameworks around employee alcohol use. Additionally, this study investigates one mechanism (i.e., sleep quality) that may help to explain how drinking links to work and well-being outcomes. Data was collected from separated post 9/11 service members and active reservists working in the civilian workforce via an internet-based survey completed in the evening over 32 consecutive days. Results indicated that within this sample of more moderate drinkers, between-person estimates were better predictors of the examined outcomes. Specifically, individuals who drank more in general tended to perceive higher levels of self-control demands and sleep less well. Additionally, between-person drinking was indirectly related to work performance, creativity, and perceived self-control demands through poor sleep quality across individuals. Examinations of the work and nonwork factors associated with work and well-being outcomes help identify risk factors that hinder employee success and provide insights into which intervention efforts may be most impactful.

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