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

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Impact of individual-level characteristics on perceptions of problematic sexual encounters

Author: 
Date created: 
2021-07-19
Abstract: 

Rates of sexual assault remain high across university settings despite increased efforts to combat this phenomenon. This project fills a gap in the existing literature by examining how situation-specific variables (i.e. alcohol consumption by and degree of familiarity between individuals) and individual-level factors (i.e., attitudes regarding sexual instrumentality and permissiveness, rape myths, trait token resistance, history of sexual victimization and sexual perpetration) relate to ongoing third-party perceptions of a sexual scenario. The current study used a vignette methodology to portray the dynamic nature of a sexual interaction between a man and a woman that began innocently but escalated to problematic behavior by the man and finally to sexual assault. At eight points in the interaction, a sample of university students (n = 350) reported their perceptions of comfort, safety, consent, and reportability of scenario. They further indicated the extent to which the scenario represented instances of sexual harassment, sexual assault, and state-based female token resistance. As the vignette’s sexual interaction became increasingly problematic, participants reported declining perceptions of comfort, safety, and state-based female token resistance, and they were more likely to characterize the interaction as lacking consent, being worthy of reporting, and involving sexual harassment and sexual assault. An analysis of situational variables within the vignette revealed no significant associations between vignette perceptions and alcohol consumption by or degree of familiarity between characters. For individual-level factors, lower rape myth acceptance was associated with identifying the interaction as lacking consent, being worthy of reporting, and as both sexual harassment and sexual assault. Trait token resistance was also related to perceptions of comfort, safety, and state-based female token resistance. These findings add to the growing literature on university sexual assault by demonstrating that third-party perceptions of sexually problematic vignettes manifest differentially among participants based on individual-level factors but not situational variables.

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

Neural mechanisms of visual singleton detection: Evidence from human electrophysiology

Author: 
Date created: 
2021-01-29
Abstract: 

It is sometimes necessary to search for visual objects of potential interest that are underspecified (e.g., any illegal item in a suitcase). The search for such an object can be accomplished easily if it possesses a unique feature that makes it stand out from its surrounding. In this case, observers can simply search for the most salient item in the environment (singleton detection). Surprisingly, the neuro-cognitive processes involved in singleton detection are still poorly understood. The overarching aims of this thesis were to reveal neuro-cognitive processes involved in singleton detection using event-related potentials (ERPs) and to address specific questions about the role of attention in singleton-detection tasks. Experiment 1 reexamined the claim that attentional processes associated with an ERP component called the N2pc are absent in singleton detection. The results revealed several ERP components, including the N2pc and a newly discovered component that tracked the time course of singleton detection (the singleton detection positivity; SDP). It was concluded that singleton detection involves some of the same attentional processes as those required for feature-based search. Experiment 2 employed a go/no-go variant of the singleton-detection task to determine whether the attentional processes observed in singleton detection are triggered automatically, as some researchers believe. ERP indices of singleton detection (SDP) and attentional selection (N2pc) were markedly reduced or absent on no-go trials, demonstrating that rapid assessment of task relevancy can prevent salience-driven capture of attention in the singleton-detection task.

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

The role of mindfulness and emotion regulation in dialectical behavioural therapy for borderline personality disorder

Author: 
Date created: 
2020-10-15
Abstract: 

Despite substantial research demonstrating its effectiveness in the treatment of borderline personality disorder (BPD), few studies have investigated mechanisms of change for dialectical behavior therapy (DBT). Improvements in mindfulness and emotion regulation have been highlighted as potential mechanisms. This study examined the time course of, and associations between, mindfulness, emotion regulation and BPD symptoms during DBT. Participants were 240 self-harming adults with BPD who were randomly assigned to receive 6- or 12-months of DBT. Results from changepoint analysis indicated that changes in emotion regulation preceded changes in mindfulness. Contrary to hypotheses, cross-lagged analyses did not indicate mediational effects of mindfulness or emotion regulation on the association of either variable with change in BPD symptoms. Supplemental analyses, however, suggested that changes in emotion regulation mediated the inverse association of changes in mindfulness with changes in BPD symptoms. Findings highlight patterns of change in proposed mechanisms of change in DBT.

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

Augmenting cognitive-behavioral therapy with parent management training to reduce coercive and disruptive behavior in pediatric obsessive-compulsive disorder

Author: 
Date created: 
2021-04-16
Abstract: 

Coercive and disruptive behaviors are common among youth with obsessive-compulsive disorder (OCD) and are thought to contribute to impairment and interfere with the effectiveness of cognitive-behavioral therapy (CBT). Parent management training (PMT) is the most empirically supported intervention for disruptive behavior problems in youth; however, no group-based PMT intervention has been adapted to address OCD-related disruptive behaviors. This study investigated the efficacy of a novel, group-based adjunctive PMT intervention among a non-randomized sample of youth receiving family-based group CBT for pediatric OCD. Linear mixed models were used to estimate treatment effects across several OCD-related and parenting outcomes at post-treatment and 1-month follow-up. Treatment response for 37 families who received the augmented program (CBT+PMT; Mage = 13.90) was compared to that of 80 families who previously received only CBT (CBT-Only; Mage = 13.93) using propensity scores and inverse probability of treatment weighting. Multiple regression models were conducted using pre-treatment characteristics and quality of participation to predict post-treatment outcomes for CBT+PMT. Families who received CBT+PMT showed significant improvements in all OCD-related outcomes and parents’ tolerance of their children’s distress at post-treatment and follow-up. Treatment response on OCD-related outcomes did not significantly differ between groups. Youths’ higher age significantly predicted greater symptom severity at post-treatment, and more severe symptoms at pre-treatment significantly predicted lower parental involvement in youth’s lives at post-treatment. Results suggest that CBT+PMT is an effective treatment for pediatric OCD across multiple indicators; however, CBT+PMT may not provide incremental benefits beyond CBT-Only, at least as presently delivered/examined. Future research is needed to determine the most effective and feasible ways to incorporate key PMT components into CBT-based interventions.

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

On quantitative issues pertaining to the detection of epistatic genetic architectures

Author: 
Date created: 
2021-01-25
Abstract: 

Converging empirical evidence portrays epistasis (i.e., gene-gene interaction) as a ubiquitous property of genetic architectures and protagonist in complex trait variability. While researchers employ sophisticated technologies to detect epistasis, the scarcity of robust instances of detection in human populations is striking. To evaluate the empirical issues pertaining to epistatic detection, we analytically characterize the statistical detection problem and elucidate two candidate explanations. The first examines whether population-level manifestations of epistasis arising in nature are small; consequently, for sample-sizes employed in research, the power delivered by detectors may be disadvantageously small. The second considers whether gene-environmental association generates bias in estimates of genotypic values diminishing the power of detection. By simulation study, we adjudicate the merits of both explanations and the power to detect epistasis under four digenic architectures. In agreement with both explanations, our findings implicate small epistatic effect-sizes and gene-environmental association as mechanisms that obscure the detection of epistasis.

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

School connectedness & attachment: Predicted and moderated relationships with substance use, depression, and suicidality among teens at-risk

Author: 
Date created: 
2020-12-14
Abstract: 

Research has demonstrated that parent-adolescent attachment security and school connectedness are protective factors that buffer teens from risk for substance use, depression, and suicidality. However, past research has examined these factors independently, and little is known about how secure attachment and school connectedness work in conjunction to reduce adolescent risk. The present study examined the moderating role of school connectedness on the relationship between parent-adolescent attachment security and substance use, depression, and suicidality among at-risk adolescents drawn from a clinical sample (N = 480; 60.5% female; Mage = 14.86). Findings indicated that for both females and males with a secure attachment, school connectedness made a positive impact to reduce symptoms of depression and suicidality, respectively. Similarly, for males with attachment avoidance, school connectedness weakened the impact of attachment avoidance on suicidality. However, for females with attachment anxiety, school connectedness was unable to reduce symptoms of depression.

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

Incident traumatic brain injury in precariously housed persons

Author: 
Date created: 
2020-11-04
Abstract: 

Persons living in precarious housing face numerous mental and physical health risks, including disproportionally higher incidence of traumatic brain injury (TBI) compared with the general population. A number of challenges hamper the existent literature on incident TBI in this population, potentially attenuating estimates of TBI occurrence. In precariously housed persons, this study (1) captured TBI events in a prospective design that included participant education regarding injury sequelae and the use of a comprehensive and validated screening tool deployed repeatedly and proximate (i.e., monthly) to incident TBI, (2) characterized the types of TBI events that occurred through detailed assessment of injury details (i.e., count, severity, mechanism, acute intoxication), with test-retest reliability analyses on self-reported injury characteristics, and (3) identified specific risk factors for incident TBI, amongst broad predictor categories (i.e., substance dependence, psychiatric illness, prior brain injury, psychological functioning), through detailed pre-injury assessment, in order to inform targeted assessment and prevention strategies. Three hundred and twenty six participants were recruited from single-room occupancy hotels and screened monthly for incident TBI. Observed and estimated rates of TBI were obtained, and logistic and poisson regression identified pre-injury risk factors for TBI occurrence, severity, and count. Across TBI definitions and approaches to missing data, incidence proportion ranged from 18.7 to 50.7 percent, event proportion ranged from 27.9 to 91.1 percent, incidence rate ranged from 30,086 to 50,674 per 100,000 person-years, and event rate ranged from 44,882 to 91,104 per 100,000 person-years. Education, role functioning, schizophrenia spectrum disorder, opioid dependence, lifetime number of TBI, and lifetime history of TBI were significant predictors of TBI occurrence. This study makes four important contributions: (1) screening for brain injury at repeated proximal assessments (i.e., monthly) obtains a considerably higher self-reported rate of TBI in precariously housed persons, (2) this multimorbid population suffers from remarkably high rates of self-reported brain injury, and (3) several key and specific risk factors for TBI occurrence and (4) TBI severity were identified. Harm reduction strategies targeting those most vulnerable are imperative to improve functioning and prevent further injury and associated consequences.

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

The role of psychological distress and sport participation on help-seeking among university student athletes

Author: 
Date created: 
2020-11-23
Abstract: 

Student athletes are considered less likely to seek help than non-athlete students despite comparable rates of mental health difficulties. However, recent findings suggest certain variables may influence these differences. The present study used a secondary analysis of a national sample of university students to explore the role of psychological distress on help-seeking among student athletes and non-athlete students. Results indicate student athletes are less likely to consider help-seeking than non-athlete students. However, the association of psychological distress and help-seeking intention did not differ across level of sport participation. Unique predictors among student athletes indicate that athletes who are in fourth year and above, had previously sought help, or were experiencing greater psychological well-being demonstrated increased help-seeking intention. Psychological distress was associated with reduced intention. This study expands upon the growing body of student athlete help-seeking research and reinforces the importance of investigating strategies to better support this unique population.

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

The relation between linguistic and manual asymmetries in bilinguals and monolinguals

Author: 
Date created: 
2020-09-22
Abstract: 

Humans are unique in their ability for language and a strong population-wide right-hand preference for object manipulation. A number of researchers (e.g., Arbib, 2005; Crow, 2002) suggest that an association between language asymmetry and handedness was crucial for human evolution and development. However, developmental studies on language and handedness association demonstrate mixed results. Importantly, only a small number of developmental studies addressed handedness-language relations in adults. Moreover, the majority of studies on handedness and language relations rely on homogeneous samples of right-handed monolingual English speakers. To this day it is not known whether the results of such studies can be extrapolated to bilingual people, and whether results obtained from studies with children can be extrapolated to adults. The current study is the first of its kind systematically examining handedness and language in a sample of over 1,800 participants with diverse language background (over 50 different languages). The study examined handedness and language asymmetry in monolinguals, early bilinguals (acquiring a second language before age 6) and late bilinguals (acquiring a second language after age 6). Additional parameters such as motor asymmetry (a preference for right footedness) and gender were also examined for potential effects on asymmetry formation in all participants. Finally, a subsample of monolingual and bilingual participants was examined on asymmetry of a gesture and object manipulation. Study results suggest that contrary to previous claims of language asymmetry and handedness association, they are not strongly related in adults. Language asymmetry and the age of the second language acquisition predicted only a small portion of handedness score. Footedness and gender were stronger predictors of handedness. Females exhibited stronger asymmetry than males; more right-footed participants tended to be more right-handed. Contrary to studies with children, current study adult participants were more strongly lateralised for object manipulation than for gesture. In conclusion, the current study suggests that handedness and language relations are dynamic in development; that their relations are not as robust as was previously suggested; and finally, that the research field of handedness-language relations would benefit from diversifying study samples.

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

Examining sense of self and identity in schizophrenia: A modified grounded theory study

Date created: 
2020-09-25
Abstract: 

Alterations or losses to one’s sense of self and identity are identified in the literature as being an important aspect of the lived experience of schizophrenia. Research further implicates regaining a sense of self and identity as playing an important role in recovery and wellbeing in schizophrenia. Despite this, a comprehensive understanding of the specific component processes involved in changes to sense of self and identity in schizophrenia has not been clearly elucidated. The current study aimed to examine and characterize the major component processes involved in alterations to sense of self and identity in schizophrenia. Using qualitative methodology, eight adult participants (age range = 31 to 55 years old, M = 45; four cisgender women, one transgender man, three cisgender men) with schizophrenia or schizoaffective disorder were individually interviewed. The interview topics included: personal understanding of the nature of schizophrenia, self-perception prior to schizophrenia, changes in self-perception through experiencing schizophrenia, coping strategies, views on current sense of self and identity, and knowledge gained about oneself through experiencing schizophrenia. Interview transcripts with analyzed using a modified Grounded Theory methodology. Five participants completed member checking procedures to verify the interpretation of the data. The data supported the conceptualization of three over-arching categories reflecting significant component processes of change to sense of self and identity in schizophrenia: (1) disruptions and interruptions to sense of self and identity, (2) finding stability, and (3) multiple pathways to (re)building a sense of self and identity through finding meaning and purpose. While the individual experience may be idiosyncratic, the findings suggest that commonalities exist in the nature of changes to sense of self and identity. The findings also indicate how individuals with schizophrenia may benefit from interventions that focus on self and identity.

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