Graduate Theses & Dissertations

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Using a real-world chopping task to study motor learning and memory
Typically task interference is studied using reaching adaptation tasks (visuomotor rotation and/or force-field learning). Participants in these experiments are already experts at the base task (point-to-point, planar reaching) and their ability to adapt reaching to the imposed perturbation is studied. The pattern of data induced by the perturbation is used to make inferences about the nature and neural correlates of our learning and memory for reaching perturbations, specifically, and motor performance in general. We wanted to see if it is possible to demonstrate this same interference pattern using a novel vegetable-chopping task, where we can easily recreate natural performance settings using a task for which we can easily identify non-experts. Participants performed a chopping task in which they are asked to chop a sweet potato into 5 mm-wide slices, matching the beat of a metronome (120 bpm). Following this initial learning, participants were exposed to an interference condition. Participants then performed trials of the original task again. Interference was inferred if the second performance of the original task was impaired, compared to initial performance. Experiment 1 involved novice choppers, and either the force or frequency of chops was manipulated. Only the altered frequency task produced interference effects. In Experiment 2, competent and expert choppers had to manage either a faster or slower frequency. We found evidence for interference in competents, but not experts. These results support the idea that the vulnerability to interference of motor memory changes with practice, and so any inferences made about memory structure must take into account not only expert performance, but every level of skill. Author Keywords: expertise, interference, motor learning, reaching adaptation
Assessing the Clinical Usefulness of Three Tablet-Based Visuomotor Tasks to Evaluate Closed Head Injury
Evidence suggests that visuomotor system behaviour may be more sensitive to the prolonged effects of mild brain injuries than neuropsychological tests. We evaluated whether participants with a mild closed head injury (CHI) would show lingering visuomotor deficits, but not cognitive deficits, up to three years post-injury compared to participants with an orthopaedic injury and healthy controls. All three groups completed a tablet-based visuomotor assessment tool and a brief neuropsychological test battery. The CHI participants scored comparable to the control groups on the neuropsychological tests, but when assessed for visuomotor function requiring adjustment to a changing stimulus, CHI participants showed poorer performance than the control groups. Combined, these findings add to the evidence that CHI can lead to persistent visuomotor deficits that extend beyond those of neuropsychological tests. Therefore, visuomotor assessment should be included in brain injury and recovery evaluation, and this can be accomplished easily using tablet-based tasks. Author Keywords: closed head injury, neuropsychological assessment, recovery, tablet, traumatic brain injury, visuomotor
Context Fear Memory
Distributing contextual fear episodes makes the memory become HPC-independent, meaning increasingly reliant on non-HPC memory structures. It is unclear, however, whether distribution of the conditioning episodes alone is sufficient or whether a combination of distribution and high conditioning saliency is necessary to make the memory become HPC-independent. To resolve this issue, rats were trained using a distributed contextual fear conditioning protocol in which foot-shocks were manipulated to create a low (0.4mA), intermediate (0.7 mA) and high (1.0 mA) saliency condition. This thesis also aimed to determine brain structures supporting the HPC-independent memory by assessing retention-induced c-fos expression in the basolateral- amygdala, perirhinal and anterior cingulate cortices. The results suggest that HPC lesion rats in the high saliency condition displayed similar level of freezing as control rats, indicating “strongly salient” and distributed episodes creates a HPC independent memory. c-fos expression suggests together, an increased context representation in the perirhinal and anterior cingulate cortices and a strengthened fear representation in the basolateral-amygdala supports the HPC-independent memory. Author Keywords: context fear memory, distributed reinstatements, hippocampus, IEG, rat, saliency
Altered Hippocampal Regulation of Immediate Early Genes after Pentylenetetrazol-Induced Seizures
Seizures induce long-term changes in gene expression in the hippocampus. Experimental evidence has demonstrated a significant effect of epileptic activity on the activity of neurons that participate in complex cognitive and behavioural processes. The present series of experiments involving kindling with subconvulsive doses of PTZ demonstrates a link between seizures and altered immediate early gene expression within the hippocampus and dentate gyrus. In addition, newborn hippocampal neurons were shown to have decreased induction of plasticity-related genes, suggesting deficits in activity-dependent recruitment. These findings may shed light on the mechanisms underlying epileptogenesis and epilepsy-related hippocampal dysfunction in human patients. Author Keywords: hippocampus, IEGs, kindling, neurogenesis, seizures
Sextual Consent
The purpose of the current study was to explore the relationships between sexting, perceptions of sexual consent, and nonconsensual sexual experiences (NSEs). Participants consisted of 100 community members and 851 undergraduate students enrolled at Trent University. It was found that males were more likely than females to interpret ambiguous sexual scenarios as consensual, but consent perceptions were not influenced by sexting. When examining past personal experiences, males interpreted received sext messages as an indicator of consent significantly more than females, while females were more likely to interpret received messages as more harassing. NSEs were significantly related to sexting behaviours: those who engage in sexting were more likely to also have experienced a NSE, and 20.5% of participants in the current study reported having experienced a NSE with a consensual sexting partner. The current study has important implications for the future of sexting research, practice, and policy. Author Keywords: nonconsensual sexual experiences, sexting, sexual assault, sexual consent, sexual harassment
Sexting and Satisfaction
Sexting was explored in relation to cohabitation status, general and sexual communication, as well as the anxious and avoidant dimensions of attachment. The present study was focused the distinction between lifetime and recent sexting, in an attempt to more accurately assess the relationships between the examined factors and sexting behaviours. Individuals in long-distance relationships were more likely to report recently sexting and engaged more frequently than those in cohabitating relationships, but did not differ in their levels of sexual satisfaction. Recent sexters reported higher levels of sexual communication compared to lifetime sexters, and sexual communication was positively, though weakly, correlated with sexting frequency. The present study was unable to support a predictive relationship between recent sexting and levels of attachment anxiety or avoidance. These results highlight the importance of exploring the context in which sexting occurs, as well as distinguishing between lifetime and recent sexters in future sexting research. Author Keywords: Attachment, Long Distance Relationship, Recent Sexting, Satisfaction, Sexting, Sexual Communication
Executive Function, Emotion Regulation, and Social Problem Solving, in Adolescence and Early Adulthood
Research to date on social problem solving typically focuses on elementary school aged children. However, adolescents and young adults may experience more novel and emotionally complex social conflicts that require different skills to navigate them successfully. Previous research has highlighted executive function (EF) and emotion regulation as possible skills that help with social problem solving. The current study examined the potential relation between EF, emotion regulation, and social problem solving. The sample consisted of 174 participants with a mean age of 19.60 years. Results showed that the shifting component of EF was associated with being able to take different perspectives when coming up with a solution for a social conflict involving a romantic partner. Additionally, emotion regulation was associate with perspective taking in the overall social problem solving process with a romantic partner. These results suggest that both EF and emotion regulation are involved in the ability to take different perspectives during a social conflict in this age range. Author Keywords: Emotion Regulation, Executive Function, Social Problem Solving
Role of Media in Shaping Perceptions of HIV and Affecting Engagement in HIV Care
Media has had a significant influence on how individuals living with and at risk of Human Immunodeficiency Virus (HIV) care for their health. This research builds on previous research to explore the link between HIV related media messaging and HIV related health behaviours using a mixed methods approach. To investigate the access to and perceptions of HIV related media, a sample of 129 individuals took part in an online survey and 13 were assessed in follow up semi-structured interviews. People living with HIV, people at risk of HIV, and participants not in those groups differed on a number of HIV media access variables, including the amount of time spent interacting with HIV related media, how they accessed it, and its perceived effects on their HIV related attitudes and behaviours. Interviews explored these differences more, finding that while current HIV related media is less stigmatizing and more factual than the past, most current HIV related media is distributed via social media and is accessed by a relatively small group of HIV specialist viewers. The history of HIV related media continues to play an important role in determining perceptions of HIV related media. Implications of this study will inform strategies for the communication of HIV health messages. Author Keywords: AIDS, HIV, Media and Health, Mixed Methodology, Social Determinants of Health, Social Media
Money for Nothing
The strong relationship between poverty and poor health has been well-established for millennia; however, the mechanisms through which this relationship manifests are only recently becoming understood. Perceptions of relative wealth and status, chronic stress, and immunodeficiencies are implicated in recent research studying the social determinants of health. The purpose of the current study is to access the detailed and contextualized perceptions of these relationships and contribute evidence-based policy suggestions to improve the health of the Canadian population. A qualitative approach was employed to provide a unique perspective in addressing the concerns identified within the literature, and fifteen semi-structured interviews with relevant experts were conducted and evaluated using a Content Analysis. The results of the current study suggested a consensus among the participants with regards to the income-related social factors which determine poor health outcomes. A basic income was also perceived to moderate these mechanisms to a certain degree, but was not considered the most effective policy solution. Emulating the progressive tax policies of more economically equal countries was the preferred approach to addressing the issues of poverty and poor health in Canada (though a basic income was not excluded as a potential subsection of these policies). A lack of political will was perceived to be one of the primary obstacles preventing such policies from coming into practice, and it was the conclusion of this paper that virtuous and knowledgeable political leaders are a necessity in the successful pursuit of improving the health of the Canadian people. Author Keywords:
Who Cares? Examining associations between caregiving sensitivity and parent-peer attachment
Although years of research have established that attachment representations are not consistently transmitted from parent to child (also known as the transmission gap), the reasons for this gap remain relatively unknown. This transmission gap exists between parents and peers as well. The purpose of this thesis was to examine the role of caregiving sensitivity in the relationship between parent attachment and peer attachment and to test if caregiving sensitivity helps explains the relationship between parent attachment and peer attachment. This study found support for the transmission of attachment from parent to peers, but not that caregiving sensitivity explains this transmission. Results indicate that parenting caregiving sensitivity questionnaires are inconsistent in assessing the construct of sensitivity. Parenting caregiving sensitivity questionnaires also do not measure the same concepts as peer caregiving sensitivity questionnaires. These findings suggest that assessing caregiving sensitivity in parents differently may help close the transmission gap. Author Keywords: attachment, caregiving, parenting, peer, sensitivity
Are We All on the Spectrum? Assessing Autistic Traits in the HEXACO Personality Framework
Autistic traits are characterized by difficulties with socialization, preference for order, and rigid and repetitive behaviour patterns. This study evaluated the psychometric properties of two measures of autistic traits, the Autism-Spectrum Quotient (AQ) and the Sub-threshold Autistic Trait Questionnaire (SATQ), and their associations with the HEXACO personality framework. The relationships between self-objectification, Need for Cognition (NFC), and autistic traits were also examined. In a student sample (N = 294), autistic traits were found to be negatively related to eXtraversion, but unrelated to self-objectification and NFC. However, individual subscales of the SATQ and AQ revealed different personality profiles, suggesting a non-unitary composition of the autistic trait measures. The AQ’s subscales failed to be represented in its factor structure. Intercorrelations between SATQ and AQ subscales showed that some subscales were uncorrelated with others. These concerns challenge whether autistic traits should be considered as a downwards extrapolation of Autism Spectrum Disorder. Author Keywords: Autism Spectrum Disorder, Autistic Traits, HEXACO, Need for Cognition, Self-Objectification
Jail Time
Children of incarcerated parents are an understudied at-risk population. However, this thesis was designed to advance our understanding of the effects of parental incarceration and factors that may influence the impact. Using quantitative methods, possible moderating roles of gender, number of incarcerated parents, and contact frequency on the associations between attachment representations and problem behaviours were investigated in two samples. Results revealed that the number of incarcerated parents and contact frequency with incarcerated parents moderated the associations between attachment and externalizing behaviours. Furthermore, after controlling for several factors (e.g., gender, number of incarcerated parents, and contact) higher scores on secure parental attachment representations were consistently negatively associated with internalizing symptoms and externalizing behaviours. The discussion of findings highlight the utility of attachment theory in conceptualizing the impact of parental incarceration and the importance of fostering attachment security to promote positive mental health and behavioural outcomes for children of incarcerated parents. Author Keywords: attachment, internalizing symptoms, parental incarceration, problem behaviours

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Graduate student theses produced at Trent University. You may also browse theses and dissertations by year, program, or author.

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