Psychology - Theses, Dissertations, and other Required Graduate Degree Essays

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Perinatal Bisphenol A administration alters reproductive and affective behaviours and physiology in adulthood

Peer reviewed: 
No, item is not peer reviewed.
Abstract: 

Bisphenol A (BPA) is a ubiquitous endocrine disrupting compound that is detectable in over 90% of Canadians and Americans. It was originally found to be an estrogenic compound, but can also act through a variety of other hormone systems, including glucocorticoids and, according to in vitro studies, also exerts anti-androgenic activity though the in vivo evidence for this claim is inconclusive. Some work has suggested that reproductive behaviours are impaired in males and there is conflicting evidence as to how emotionality may be affected. However, this field of research has been somewhat controversial, as governments worldwide have accepted that BPA is safe at low doses, despite the experimental and epidemiological evidence that low doses are in fact more likely to exert negative effects. As such, this research program is examining a wide range of doses of BPA administered to rats both pre- and postnatally. Reproduction, anxiety, learning and learned helplessness were then tested in adulthood. This data indicates that low doses of BPA administered perinatally can inhibit the reproductive behaviour of males even after multiple experiences, can demasculinize males in anxiety and depressive-like behaviours, and alters the expression of estrogen receptors in the medial amygdala. However, perinatal BPA administration did not alter the survival or soma size of motor neurons controlling penile musculature. Chronic administration during adulthood did reduce soma size in both sexually dimorphic and monomorphic motor neurons, suggesting a non-androgenic mechanism of action. The implication of these data on policy surrounding human exposure to BPA is discussed.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Neil Watson
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis/Dissertation) Ph.D.

Hurting the healers: stalking in the mental health professions

Date created: 
2012-06-25
Abstract: 

A growing body of research suggests that mental health professionals (MHPs) are more likely to be victims of stalking than are members of the general public, yet less likely to report their victimization to police. The present study attempted to increase the evidence base on stalking of MHPs by surveying the experiences of Registered Clinical Counsellors in British Columbia, Canada. All members of the provincial professional association for Registered Clinical Counsellors were contacted, and N = 346 completed an on-line survey (response rate = 17%). The survey included questions to determine the prevalence and nature of stalking victimization, focusing on stalking that occurred in the context of the respondents’ work as MHPs; the impact of the stalking and the strategies respondents used to cope with it; and respondents’ knowledge of and attitudes toward stalking. Results indicated that many respondents had experienced individual stalking-related behaviours. The lifetime prevalence of stalking victimization perpetrated by clients was 7% (SE = 1%), a rate consistent with that found in other types of MHPs and in other countries. The characteristics of stalking perpetrators were similar to those reported in previous research. Victims often had problems coping with victimization due to limited knowledge about the phenomenon of stalking, engaging in behaviour that is generally considered ineffective or even counter-productive when responding to stalking, and inadequate access to external resources. Overall, about half of respondents were unaware that MHPs were at increased risk for stalking victimization and many endorsed the view that stalking victimization is caused by poor clinical skills. The implications of these findings for the prevention of and responses to the stalking victimization of MHPs by clients are discussed.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Stephen Hart
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Dissertation) Ph.D.

“You have to have the relationship”: a youth perspective on psychotherapy and the development of a therapeutic relationship

Author: 
Date created: 
2012-12-05
Abstract: 

This study used qualitative methodology to examine the opinions of adolescents regarding the formation of a therapeutic relationship and engagement in individual therapy. Adolescents face the challenge of coping with significant and concurrent biological, psychological, and social changes while completing a variety of developmental tasks, including identity formation, separation from caregivers, and gaining peer acceptance. The stress of having to navigate through this developmental period can often manifest as mental illness, requiring therapeutic intervention. However, due to the unique developmental issues facing adolescents, it is more difficult to conduct therapy with this age group. In particular, the task of forming a therapeutic relationship, which is a critical component of successful therapy, is more challenging with adolescents than any other age group. Given the significant emotional distress experienced by adolescents today, in combination with their negative attitudes towards, and dissatisfaction with, therapeutic services, it is necessary to determine methods for optimizing the benefits received from these services. An effective approach to service enhancement is to solicit the opinions of consumers and integrate these findings into practice. In the present study, fifteen adolescents with extensive experience in individual therapy were interviewed and a qualitative analysis using grounded theory was conducted. The adolescents discussed the ideal ways in which they would want therapists to interact with them to facilitate the formation of a strong therapeutic relationship. Four therapist attributes or qualities were identified, including respect, responsiveness, “genuine caring”, and authenticity. Respect denotes the importance of an egalitarian and accepting relationship, while responsiveness involves tailoring the therapy experience for each youth. “Genuine caring” includes being sincerely interested in and committed to the youth, while authenticity highlights the value of therapists revealing their personalities. The adolescents also discussed the structural aspects of therapy that were perceived as being beneficial, such as “venting” to someone who is “removed” from their social and family lives, as well as the challenges associated with the initial stages of therapy. The clinical implications of these findings and the obstacles to providing youth with their ideal experience are discussed.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Robert Ley
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Dissertation) Ph.D.

Neurocognitive profiles of marginalized persons with comorbid substance dependence, viral infection, and psychiatric illness

Date created: 
2012-10-25
Abstract: 

Individuals living in single-room occupancy (SRO) hotels constitute a marginalized population with exposure to adverse risk factors, including substance use, viral infection, and psychiatric illness. The current study used cluster analysis to identify and describe subgroups of individuals with common profiles of neurocognitive functioning in 249 SRO residents. Results revealed three distinct subgroups. Cluster 1 (n = 59) presented as higher functioning, whereas Cluster 3 (n = 87) exhibited the lowest functioning with a relative strength in decision-making. Conversely, Cluster 2 (n = 103) was characterized by neurocognitive abilities that bisected the performance of the other groups, but with a relative weakness in decision-making. A discriminant function analysis revealed that the neurocognitive variables comprised two dimensions that accounted for between-group variance. Clusters meaningfully differed on several external variables. Overall, this study revealed that neurocognition provides the basis for identifying meaningful subgroups of individuals and may be informative to intervention strategies.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Allen Thornton
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

Sleep and circadian organization as regulators of adult hippocampal neurogenesis

Author: 
Date created: 
2012-11-16
Abstract: 

The functions of sleep and hippocampal neurogenesis are topics of current research and remain unresolved. Both are suggested to play a role in hippocampus-dependent memory processes and in the development and symptoms of stress and depression. Total sleep deprivation, sleep fragmentation and rapid-eye-movement sleep deprivation (RSD) have been shown to reduce hippocampal neurogenesis, suggesting a functional link between sleep and neurogenesis, but the underlying mechanism remains unknown. To shed light on this issue, we subjected adult, male rodents to long-term RSD, using the platform-over-water method. In addition, we provided adrenalectomized (ADX) rats with a subcutaneous osmotic minipump, resulting in a constant low dose of corticosterone (CORT) supplementation to prevent elevated levels of CORT, a known inhibitor of cell proliferation. A side effect of the RSD procedure is the suppression of daily behavioural rhythms. To test a role for this in the antineurogenic effect of RSD we disrupted behavioural circadian organization by constant bright light exposure. In a final set of experiments, we examined the role of the pro-inflammatory cytokine interleukin-1-beta (IL-1β), using two approaches. First, we assessed the effect of elevated IL-1β by lateral ventricle injections. Second, we inhibited IL-1β signalling using IL-1RI receptor knockout mice and subjected intact and ADX animals to the RSD procedure. Immunohistochemical analysis of 5-bromo-2’-deoxyuridine, Ki67 and doublecortin provided information on hippocampal cell proliferation, differentiation and survival. Here we show that RSD consistently reduced hippocampal cell proliferation, independent of adrenal stress hormones and that the CORT supplementation technique is critical to detect this effect. Furthermore, the data suggest that RSD is antineurogenic independent of species, strain, social interaction, proliferation marker and activity level. The results show in addition that neither disrupted circadian organization nor melatonin suppression reduces hippocampal neurogenesis. Studies in IL-1RIKO mice demonstrate that eliminating IL-1β signalling alone is not sufficient to suppress the inhibitory effect of RSD on cell proliferation. However, the data suggest that eliminating both non-specific stress responses (CORT and IL-1β) together can eliminate the antineurogenic effect of RSD. Thus RSD might reduce hippocampal neurogenesis via multiple secondary mechanisms as part of a stress response.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Ralph Mistlberger
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) Ph.D.

To engage or disengage? How group-based coping options explain the relationship between group identification and well-being for disadvantaged groups

Date created: 
2012-11-02
Abstract: 

Although data suggests that a sense of shared social identity can contribute positively to psychological well-being for members of disadvantaged groups, little research has directly investigated the mechanisms involved in this relationship. In this study I test the ability of group identification to foster group-based engagement coping options (i.e., collective action, emotional expression, ingroup social support) that should promote well-being. I also tested the ability of identification to deter group-based disengagement coping options (i.e., avoidance, individual mobility, ingroup blame) that should harm well-being. These mediational processes were examined with samples of women, Blacks, gay people (gay men and lesbians) and deaf people. Supporting prior research, across the four samples higher group identification was associated with greater self-esteem and life satisfaction. Each coping option was found to be a mediator to varying degrees across the four samples. However, for gay people and Blacks more coping options mediated the relationship of identification with both self-esteem and life satisfaction. As a whole, the mediational results suggest that identification promotes well-being, in part, because it encourages group-based beliefs about engaging with discrimination and discourages group-based beliefs about disengaging from discrimination. Group differences in both the endorsement of coping options and the coping options that best accounted for the relationship between group identification and well-being are discussed in terms of politicized collective identities and concealability.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Michael Schmitt
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Dissertation) Ph.D.

Communication as a moderator of the interplay between newlyweds’ sexual and relationship satisfaction

Date created: 
2012-08-27
Abstract: 

I examined reciprocal contemporaneous and time-lagged associations between marital and sexual satisfaction in heterosexual newlywed couples (N = 189), and whether positive (empathy, perspective taking) or negative (e.g., hostility, insensitivity) communication indicators moderated this association. Multilevel modeling indicated that sexual and relationship satisfaction co-varied, and that sexual satisfaction predicted increases in marital satisfaction, but the opposite was not true. Contemporaneously, good quality communication strengthened the positive association between marital and sexual satisfaction as the outcome, but did not moderate the association when marital satisfaction was the outcome. Communication quality did not interact with sexual satisfaction to predict changes in marital satisfaction, but did interact with marital satisfaction to predict sexual satisfaction. A cross-over interaction suggested that marital satisfaction predicted increases in sexual satisfaction when communication quality was positive, but declines when communication quality was less positive. Results highlight the importance of the sexual relationship to marital satisfaction in early marriage.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Rebecca Cobb
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

Measuring the Hebbian components of selective attention using eye-tracking and dynamic field theory

Date created: 
2012-08-10
Abstract: 

A technique for measuring the relative strengths of associative learning of eye- movements is introduced. In experiment designs that manipulate feedback signals, the strength of the learning associated with the signal can be measured by looking at the amount of perseveration to irrelevant information after a learning criterion is met. In contrast to previous models of attentional learning, shifts of attention are explained primarily by the joint influence of habituated motor movements and the gain derived from the anti-correlated components of abstract categories. For this to work, a realistic model of ocular-motor movements is required in order to ground the concept of attentional allocation. A dynamic neural field model of eye-movements is thus presented which captures a number of the mesoscopic neurodynamics known to influence visual attention during learning. Under a number of different simulation constraints, this model shows an ability to fit aspects of human performance.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mark Blair
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

The influence of salience and similarity on selective attention

Date created: 
2012-08-15
Abstract: 

A previously reported effect of similarity on reaction times in a categorization task (Hahn et al., 2010) is tested and extended by using eye trackers as a measure of visual attention. The original effect was not found using a new stimulus set, suggesting that delayed reaction times are not a result of dissimilarity but are due, in part, to the properties of the stimuli. The elements of the stimulus reflecting similarity to the training set, but irrelevant to categorization, are made salient to test this idea. The reaction time effect is not replicated, but a surprising result is found in the eye tracking data: attention to irrelevant information is less likely when the irrelevant information is salient. This finding cannot be explained completely by existing models, so a new way of thinking about visual attention is provided in a proposed model of integrated bottom-up and top-down visual attention processes.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mark Blair
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

Electrophysiological correlates of emotional face processing in typically developing adults and adults with high functioning Autism

Date created: 
2012-05-31
Abstract: 

Emotional expressions have been found to affect various event-related potentials (ERPs). Furthermore, socio-emotional functioning is altered in individuals with autism, and a growing body of neuroimaging and electrophysiological evidence substantiates underlying neural differences for face processing in this population. However, relatively few studies have examined the time-course of emotional face processing in autism. This study examined how implicit (not the intended focus of attention) versus explicit (the intended focus of attention) presentations of emotion differentially influenced the processing of fearful, sad, and happy facial expressions relative to neutral expressions. Study 1 was conducted in a sample of typically developing (TD) young adults. Study 2 compared a group of high-functioning young adults with autism to a new group of age-, gender-, and IQ-matched TD controls. Results from both studies supported the prediction that ERP components would be differently modulated as a function of emotion relevance and emotional expression, suggesting different emotions and implicit/explicit presentations are processed in partially separable neural networks. Both studies found that sad faces uniquely modulated the P150, VPP, EAP, and LPP in TD adults. This unique response to sad faces was found as early as 150ms post-stimulus onset over frontal electrodes, suggesting early, relatively automatic recognition of sad faces. It was also found over posterior sites as indexed by the LPP, reflecting more conscious appraisal of the emotion. In individuals with autism, sad faces did not elicit distinctive effects. Rather, happy faces uniquely modulated the P150 and N4a, suggesting that this positive social emotion was most salient to adults with autism whereas sad faces, which may communicate a social error message and elicit empathy, were most salient to TD adults. Both experiments provide support for a neural network that is sensitive to socially relevant information and provide important clues for underlying neural differences that may contribute to difficulties with socio-emotional functioning so commonly reported in autism.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mario Liotti
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis/Dissertation) Ph.D.