Recent Submissions

  • Using the HEXACO to Capture Psychopathy: Development and Initial Validation of the Power Proxies of Psychopathic Traits

    Power, Jordan P.; Department of Psychology
    Psychopathy, though often considered an abnormal personality construct, has been repeatedly found to be related to “normal” personality traits, and the HEXACO model of personality is particularly capable of capturing the “dark” personality variance integral to the construct. Additionally, while previous research indicates that psychopathy can be applied to both sexes, it has been suggested that psychopathic traits are expressed somewhat differently between men and women. In Study 1, we examined the relations between the Self-Report Psychopathy Scale (SRP) and the HEXACO-60 in a student sample (n = 1,346) in order to create proxy measures for Hare’s two-factor/four-facet model of psychopathy and to investigate sex differences in the associations between the SRP and the HEXACO. We created “general” proxies for use with samples of men and women in addition to male- and female-specific proxies for potential use with samples of exclusively men or women, respectively. The proxies had good psychometric properties and had stronger correlations with several psychopathy-relevant variables than did a previous attempt to measure the SRP facets using HEXACO items. In Study 2, we investigated how the proxies would function in a youth community sample (n = 396). The proxies related to many external variables in a similar manner as that of a previously validated measure of psychopathic traits in youth, suggesting that the proxy scales can be used with younger populations. In Study 3, we used a MTurk sample (n = 471) to update the proxy scales with HEXACO-100 items and to investigate sex differences in the relations between the SRP and the new HEXACO items. Several items were added to each version of the proxy scales and, compared to the original proxies, the updated proxies displayed better psychometric properties and stronger correlations with psychopathy-relevant variables. Overall, this program of research demonstrates considerable overlap between Hare’s model of psychopathy and the HEXACO model of personality. Honesty-Humility and altruism seem to underlie all of the psychopathy scales, whereas aspects of the other HEXACO domains tend to differentiate the psychopathy scales from one another. Further, several sex differences in how psychopathic traits relate to basic personality were identified.
  • Investigating the Conditional Adaptiveness of Adolescents’ Aggression from an Evolutionary Perspective

    Lapierre, Kiana; Department of Psychology
    Growing evidence supports the evolutionary perspective characterizing aggression as a strategy to achieve proximate adaptive benefits which can indirectly and probabilistically contribute to ultimate evolutionary goals (survival and reproduction). However, aggression may only be adaptive under certain conditions. Therefore, this dissertation investigated various conditions that may affect the adaptiveness of adolescent aggression, namely aggression characteristics (aggressive form, function, and anonymity), target characteristics (power of victim relative to the perpetrator), and perpetrator characteristics (experience of victimization and gender). Study 1 used a person-oriented approach to investigate how proactive and reactive cyber aggression and concurrent experiences of cyber victimization were associated with evolutionarily relevant social advantages and disadvantages in a community sample. Study 2 examined differential associations between aggression involvement and evolutionarily relevant aggressive functions, considering variations in aggressive form, the target’s power relative to perpetrator, and the perpetrator’s gender in a school-based sample. Finally, in a school-based sample, Study 3 investigated (1) how the associations between anonymous perpetration and evolutionary functions of aggression varied by aggressive form and the perpetrator’s gender, (2) how the target’s power and the perpetrator’s gender related to adolescents’ use of anonymous perpetration in each aggressive form, and (3) differential associations between anonymous victimization and victims’ perceptions of harm as a function of aggressive form and gender of the victim. Results suggest that adolescents’ aggression was linked to evolutionarily relevant aggressive functions motivated by competitive (e.g., aggression deterrence, intrasexual competition), impression management (seeking status and mates), sadistic (enjoyment), and reactive (impulsive response to real/perceived threats) functions, and to social advantages (social dominance, dating behaviour) for aggressors who used reactive aggression less frequently. However, aggression involvement was differentially associated with evolutionary motives based on the form, function, or anonymity of aggression, target characteristics, and perpetrator characteristics. Moreover, aggression was associated with costs, especially for cyber aggressor-victims who frequently aggressed reactively, and for victims of anonymous aggression. Thus, adolescents’ aggression may be conditionally adaptive for a narrow range of functions, depending on the characteristics of the aggression, target, and perpetrator. By highlighting the conditional adaptiveness of adolescent aggression, this research may inform efforts to improve interventions addressing aggression.
  • Children’s Developing Use and Understanding of Coercive Language: Applications in a Legal Setting

    Wylie, Breanne; Department of Psychology
    Within adult-child interactions, where children may be the target of coercion, it is important for children to understand and accurately describe their experiences. Coercive language is expressed using deontic modals, distinguishing between terms of obligation (i.e., implying compliance is required) and permission (i.e., implying compliance is optional). Children’s ability to understand and use coercive language is particularly relevant within applied legal settings where children may be required to testify about coercive tactics, and jurors may use this information to form perceptions about the case. Across three studies, my dissertation examined children’s understanding and use of coercive language, and the influence of using terms of obligation and permission on jurors’ perceptions of children’s reports. In Study 1, I examined 160 3- to 6-year-olds' understanding of the deontic modals tell and ask (referring to obligations and permissions) compared to their epistemic understanding of these terms (referring to knowledgeable and ignorant conversationalists), and the role of theory of mind in their understanding. In Study 2, I examined attorney and children’s use of coercive language within 64 transcripts of children’s testimony for cases involving alleged sexual abuse. In Study 3, I examined the influence of coercive language and maltreatment type on 160 adults’ perceptions of coercion and the child, as well as their judicial decision making. Overall, children’s understanding of the terms tell and ask emerged around 5 years of age, supported by their developing theory of mind. Additionally, children (as young as 6 years) and attorneys used terms of obligation and permission to describe coercion, and jurors were sensitive to these linguistic differences, perceiving children using terms of obligation as more coerced and the adult as more to blame. Of benefit, jurors’ decision making was not influenced by language, but rather focused on the nature of the abuse. Altogether these studies provide insight into children’s developing understanding of coercive language and suggest that even when used appropriately by 5 years of age, terms of permission minimize perceptions of coercion and adult blame. These findings demonstrate the need for educating adults about factors (e.g., coercive language) that may influence their perceptions of children’s disclosure.
  • Novel ways to measure future-oriented cognition: Using parent-report measures and open-ended responses to explore young children’s future thinking development

    Mazachowsky, Tessa; Department of Psychology
    Future-oriented cognition encompasses a set of key abilities that children must develop for successful functioning in daily life including, saving, prospective memory, episodic foresight, planning, and delay of gratification. These future thinking abilities are supported by memory systems (e.g., semantic, episodic), as well as constructive processes, self-projection, and executive functions. Research primarily measures young children’s future-oriented abilities through behavioural tasks, which have various limitations and may not engage future thinking. The current studies introduce new methods to overcome some of these limitations: developing a parent-report questionnaire and examining children’s open-ended responses. In Study 1 (N = 101; Mazachowsky & Mahy, 2020), 3-to 7-year-old’s future thinking was examined to establish the psychometric properties of a new parent-report measure, The Children’s Future Thinking Questionnaire (CFTQ). The CFTQ detected development of children’s future thinking and is a reliable and valid measure. Study 2 (N = 48; Mazachowsky et al., 2020) examined 3-to 5-year-old children’s episodic foresight using a novel, open-ended version of the Picture-book task. Results showed that children were able to generate items for future use and were more successful with age. Children’s explanations for their generated items were typically present-focused and included both episodic and semantic details. Expanding on Study 2, Study 3 (N = 158; Mazachowsky et al., revisions requested) explored 3-to 5-year-old’s explanations for their item choices on two episodic foresight tasks to determine the degree to which these tasks engaged children’s episodic and future-oriented processes. Children provided more future-oriented explanations on the Picture-book task compared to the Spoon task, but episodicity did not differ between tasks. Further, children’s Picture-book task explanations included more first-person personal pronouns compared to the Spoon task, but explanations did not differ in other pronoun use. Together, these studies show that use of a parent-report measure and examination of children’s open-ended responses offer unique insight into the development of young children’s future thinking and engagement in future-oriented processes.
  • Do we become more honest as we age? A multi-methodological approach to studying dishonesty across adulthood

    O'Connor, Alison; Department of Psychology
    Being dishonest with others is a common social behaviour, and it has been proposed that dishonesty increases throughout childhood, peaks in adolescence, and gradually declines across adulthood (i.e., an aging-honesty-effect among older adults). Yet, very little research has comprehensively explored how dishonesty is used and evaluated in later life. Using a multi-methodological approach, the primary goals of my dissertation were to examine if this aging-honesty-effect replicated across methodologies and social contexts and to provide a deeper understanding of the deceptive profiles of older adults to uncover what they lie about, who they lie to, and how they morally evaluate lies. In Study 1, I measured younger and older adults’ willingness to cheat in a spontaneous deceptive paradigm and personality traits of honesty-humility. In Study 2, younger and older adults completed an experience sampling study where they recorded their daily lies for a 7-day period. In Study 3, younger and older adults morally evaluated truths and lies, and participants were recruited in Canada, Singapore, and China to examine if age differences were culturally dependent. Results supported the proposed aging-honesty-effect where older adults were less likely to cheat in a task when given the opportunity (Study 1), they scored higher in the honesty-humility personality trait (Study 1), and they told fewer lies across a 7-day period (Study 2) compared to younger adults. Extending these results beyond lie frequency, Study 2 provided insight into the ways in which younger and older adults use lies in their natural social lives, uncovering that this aging-honesty-effect can vary depending on the type and topic of the lie and the relationship between the liar and the lie recipient. Finally, Study 3 found that not only are older adults more honest themselves, but they evaluate blunt or immodest honesty more favorably and good-intentioned lies less favorably than younger adults, and these effects persisted beyond a Western cultural context. These results provide the foundation for understanding older adults’ use and evaluation of dishonesty and can contribute to constructing a lifespan model of dishonesty from childhood through to old age.
  • The development of sensitivity to threat among children and adolescents

    Heffer, Taylor; Department of Psychology
    Several theories of adolescent brain development suggest that adolescence is a sensitive period of development characterized by the onset of internalizing problems, such as anxiety. Sensitivity to threat, a heightened responsiveness to aversive situations, has been suggested to be a precursor to anxiety, highlighting the importance of understanding sensitivity to threat among children and adolescents. Yet relatively little is known about the development of sensitivity to threat. Further, identifying the neural indicators that are associated with heightened sensitivity to threat would help classify which youth are most at risk for anxiety. The primary goals of my dissertation were: 1) to explore whether adolescents, compared to children, have heightened sensitive to threat, 2) assess which neural indicators are associated with heightened sensitivity to threat, and 3) assess whether individual differences (e.g., in consistency of sensitivity to threat across time and situation) help predict which youth are most at risk for anxiety-related problems. Study 1 of my dissertation examined, with concurrent data, whether adolescents have greater neural sensitivity to negative feedback compared to children. Study 2 examined whether children and adolescents differ in their longitudinal trajectories of sensitivity to threat (e.g., consistency across time). I also was interested in whether these trajectories were associated with frontal asymmetry, a neural indicator associated with avoidance motivations. Study 3 extended the findings from Study 2 to examine consistency across threatening situations. While Studies 1 through 3 investigated whether adolescence is a period of heightened sensitivity to threat, Study 4 of my dissertation used a latent class analysis to investigate whether individual differences in sensitivity to threat, impulsivity, and emotion dysregulation are associated with anxiety and/or risk taking. Results indicated that adolescence (especially when defined by pubertal status), may be a normative period for sensitivity to threat. At the same time, not all youth who are sensitive to threat go on to develop anxiety; thus, it may be that for many adolescents, sensitivity to threat is an adolescent-limited phenomenon, meaning that threat sensitivity may peak in adolescence, but then tapers off into adulthood. Importantly, neural indicators associated with threat sensitivity helped identify which youth may have the highest levels of threat sensitivity. Overall, my dissertation shows that while some level of sensitivity to threat is normative, it is less common for youth to be consistently sensitive to threats and importantly, these youth who are consistently sensitive appear to be most at risk. Taken together, the four studies of my dissertation incorporate EEG, longitudinal designs, multiple indicators of development (age and pubertal status), and self-report data to gain a holistic understanding of sensitivity to threat from childhood to adolescence.
  • Extending Intergroup Contact Theory to Men’s Anti-Women Biases

    Earle, Megan; Department of Psychology
    Men’s exploitation of women in heterosexual relationships is commonplace, both through sexually assaulting or otherwise taking advantage of women’s bodies, and in exploiting women for domestic labour such as housework and childcare. In the current investigation, we first present evidence for the co-occurrence of men’s willingness to sexually exploit and their willingness to domestically exploit their partners, then assess predictors and emotional processes underlying such hostility. Specifically, in Chapter 2, we develop a two-dimensional scale of willingness to exploit women with male participants (Study 1a; n = 103) and provide evidence that sexual exploitation willingness and domestic exploitation willingness are indeed separate, but related, factors. In Study 1b, we perform confirmatory analysis of this measure in two additional samples (n = 129 and n = 632 respectively) and provide evidence of construct validity for the scale. Then, Study 1c (n = 281) we provide evidence for stability of the construct over time, as well as its ability to predict behavioural indicators of exploitation. In Chapter 3, we investigate predictors and emotional processes underlying anti-women hostility and willingness to exploit women drawing on intergroup contact theory. In a correlational investigation (Study 2; n = 229), we find that perceived negative experiences with women predict greater anti-women bias via greater anger toward women. We then confirm this pattern of results using an experimental manipulation in Study 3 (n = 174), finding indirect effects of anger toward women in the relation between negative contact condition (vs. control) and greater anti-women bias. Positive contact, in contrast, has little relation with more positive attitudes toward women. Finally, in a three-wave longitudinal investigation (n = 577), Study 4 presents evidence for more nuanced relations between perceived contact, anger, and anti-women hostility; the findings suggest that not only do negative contact experiences predict downstream anger toward women, but also that anger and anti-women attitudes feed into men’s perceptions of their contact experiences with women. Overall, these findings reveal that perceived negative (but not positive) contact with, and anger toward, women are particularly relevant to understanding anti-women biases in heterosexual relations and future directions for reducing anti-women hostility are discussed.
  • An In-depth Examination of Personality and Aggression Across Different Contexts

    MacDonell, Elliott; Department of Psychology
    Acts of aggression are associated with a variety of negative outcomes. Accordingly, research has aimed to identify the personality traits that give rise to different forms of aggressive behaviour. Recent work has indicated that the factor of Honesty-Humility is associated with a variety of deviant behaviours, including aggression towards others; however, the nuances of these relationships require further investigation. This dissertation aimed to address several gaps in this literature through three main studies. In Study 1, we extended previous findings to younger populations, examining the associations between Honesty-Humility and aggression longitudinally in a large sample of children and youth. These findings demonstrated a bidirectional relationship between Honesty-Humility and aggression over time, such that low levels of Honesty-Humility resulted in higher levels of aggression and vice versa. In Study 2, we explored the specific facets of Honesty-Humility to determine if they differentially predict proactive and reactive aggression. Despite the theoretical link between Modesty and reactive aggression, we found limited support for this association, especially when controlling for proactive aggression. Overall, the Sincerity and Fairness facets were found to strongly predict both forms of aggression. Lastly, Study 3 explored the associations between Honesty-Humility and deviance, aggression, exploitation, and victimization in a workplace context. Robust relationships were found between Honesty-Humility and several deviant behaviours, further emphasizing the importance of this trait. In particular, when provided with the opportunity to aggress, individuals low in Honesty-Humility were more likely to do so, regardless of their level of power in the situation. Collectively, these findings indicate that Honesty-Humility is the strongest predictor of aggressive and deviant behaviour among the broad factors of personality. However, this dissertation extends previous findings by demonstrating the applicability of Honesty-Humility across different contexts and by providing a nuanced understanding of the components responsible for this relationship.
  • The Mental Representation of Visual Information

    Robitaille, Joel; Department of Psychology
    Despite working in relative independence, the working memory and imagery literatures investigate the mental representation of visual information. Recent reports investigating the neural structure and their associated functional activity responsible for the creation and maintenance of these cognitive representations suggest a significant overlap between these fields of study. Because each field has adopted methodologies that does not allow for a direct comparison of the mental representation described by their respective literatures, it is difficult to determine whether imagery and working memory representations are related. Hence, the current thesis further investigates the properties of the visual representation of visual information to bridge between the imagery and working memory fields. In a first study, I compare the psychophysical properties of simple stimuli commonly used in working memory reports with more complex objects adopted by the imagery field. In the course of three experiments, I demonstrate that the cost of stimulus complexity predominantly affects the quality of the mental representation while still providing evidence of a shared cognitive mechanism driving the formation and maintenance of these representations. In a second study, I evaluate the impact of mental rotation on these mental representations as well as whether the adoption of different paradigms, along with different performance metrics, assess the same cognitive construct. Here again, I show strong evidence in support of a common cognitive mechanism driving the performance across mental manipulation and through assessment methods. Finally, the last study attempted to track the manipulation of these visual representations by applying an encoding model to raw EEG activity. While I show evidence of the orientation-relevant activity during perception, the encoding model does not detect reliable enough activity to allow for tracking the orientation of the stimulus during retention and mental rotation. Together, this thesis provides evidence of a shared cognitive mechanism that drives visual working memory and imagery representation, but tracking these mental representations using EEG activity during manipulation remains unclear.
  • Learning and recognizing faces across variability in appearance: An examination of children and older adults

    Matthews, Claire M.; Department of Psychology
    Recognizing facial identity requires two skills: telling a person apart from similar looking people and recognizing them across changes in their appearance. Until recently, the vast majority of studies relied on tightly controlled images to examine face learning and recognition. Research using ambient images (i.e., images that capture within-person variability in appearance) is necessary to assess the true challenge of face learning and recognition in daily life. Only a few studies have examined face learning and recognition using ambient images in children, and, to the best of my knowledge, no studies have examined them in older adults. My dissertation was designed to address these gaps in the literature. In Study 1, children aged 6 to 11 were tested to examine two mechanisms that underlie face learning in young adults: Ensemble coding and the ability to benefit from exposure to variability in appearance in a perceptual matching task. My results revealed that both mechanisms are adultlike by the age of 6. First, children extracted the average of a set of images of an identity, regardless of whether those images were presented simultaneously or sequentially. Second, although their overall accuracy was lower than that of young adults, children showed comparable benefit from viewing multiple images of a to-be-learned identity in a perceptual face learning task. In Study 2, I examined whether younger children (4- and 5-year-olds) benefit from exposure to multiple images when learning a new face in a perceptual task. Although viewing multiple images made young children more sensitive to identity, it also led them to adopt a less conservative response bias, driven both by an increase in hits and an increase in false alarms. This increase in false alarms was not found for older children and adults in Study 1, suggesting that the ability to benefit from exposure to variability in appearance during face learning is not fully refined before the age of 6. In Study 3, I provided the first examination of face learning and recognition in older adults using a battery of tasks. On three of the five tasks, older adults showed comparable learning and recognition to young adults: 1) Older adults recognized a familiar face without error; 2) they showed ensemble coding of facial identity, regardless of whether the images were presented simultaneously or sequentially and 3) despite making more errors than young adults overall, they showed comparable benefit from viewing multiple images of a newly encountered face in the perceptual learning task. In the remaining two tasks, older adults showed a different pattern than young adults: 1) Older adults made fewer hits and more false alarms than young adults when matching images of wholly unfamiliar faces; and 2) after being exposed to low variability in appearance in a face memory task, older adults became more conservative than did younger adults, despite showing comparable benefits in sensitivity. My results reveal that the same abilities that show prolonged development during childhood are those undergo changes in aging. Collectively, my dissertation provides novel insights about learning and recognizing facial identity during childhood and aging and has important implications for understanding models of face processing.
  • Understanding the Complex Mental Health Challenges of Children and Adolescents Seeking Community-based Care

    Gallant, Caitlyn; Department of Psychology
    Studies have shown that children and adolescents with neurostructural and/or neurodevelopmental challenges experience worse mental health outcomes than their neurotypical peers, including more extensive service use, more severe symptomatology, and greater functional impairment. Despite the poor prognoses of these children and adolescents, few studies have investigated the neurocognitive contributions to mental health complexity among those seeking community-based mental health services. At present, environmental/social and behavioural factors remain the primary focus of treatment plans and much of the research examining this complex population has targeted psychosocial determinants. However, interventions based on these factors alone are not always effective, as they fail to account for neurocognitive challenges, which can significantly contribute to psychiatric presentations. This dissertation involves two studies that aimed to address these gaps in the literature and inform current practices in paediatric community mental health settings. Using Structural Equation Modeling (SEM), Study 1 tested the generalizability of a path model predicting service use among those with (n = 66) and without (n = 97) neurodevelopmental disorders (NDs). As expected, those with NDs had higher levels of symptomatology and greater service use than those without, and there were notable differences in the predictive pathways across ND groups. Similar paths were found between externalizing challenges and service use among all children/adolescents; however, the paths from internalizing challenges, early life adversity, and sex were only significant among the ND group, indicating that neurodevelopmental status is an important moderator of outcomes. In Study 2, a mixed methods approach was employed to examine how neuropsychological information could help inform current practice. Qualitative results confirmed that neuropsychological factors are often overlooked when utilizing current approaches and that observable symptoms, rather than underlying causes, are a primary focus of treatment. Further, neurocognitive deficits were found to be associated with self-reported interpersonal difficulties and caregivers’ reports of externalizing; however, only caregiver-reported externalizing challenges correlated with poorer treatment outcomes. Importantly, neurocognitive challenges were associated with long-term treatment responses, suggesting that these factors may be an important therapeutic target. Collectively, these findings indicate that using an exclusively psychosocial treatment approach, without considering neuropsychological factors, may not be effective among complex cases.
  • The interaction of sleep and hormones on emotion functioning

    Lustig, Kari; Department of Psychology
    Insufficient sleep has been associated with deficits in emotion processing; sleepy individuals show increased emotional reactivity and decreased emotion regulation. Individual differences that predict performance after sleep loss has remained largely elusive. Concentrations of cortisol, progesterone, and testosterone are candidate predictors for variability in performance following sleep loss. These hormones are associated with emotion functioning under well-rested conditions and show interactions with sleep and circadian rhythms. The central aim of this dissertation was to investigate the interaction of natural sleep and hormones on measures of emotion functioning. Study 1 examined the role of cortisol in the relationship between sleep (across the first three years of university), and self reported emotion functioning in undergraduate students. Poor sleep was associated with worse emotion regulation and reactivity, and greater concentrations of cortisol and cortisol/DHEA-S. Consistently poor sleepers over three years, who had high cortisol, experienced the greatest difficulties with emotion regulation. Study 2 investigated the association between sleep satisfaction and objective measures of sleep on self-reported emotional functioning in a group of children and adolescents. Importantly, in girls who were dissatisfied sleepers, being further though puberty was associated with the greatest difficulties with emotion regulation. Study 3 examined natural sleep, hormones, and menstrual phase on processing emotional stimuli. Participants completed sleep diaries and wore actigraphy watches for 3-weeks and completed measures of emotion perception on two occasions in the laboratory, in different menstrual phases for women. The study supported dynamic relationships between hormone concentrations and various measures of sleep duration and quality on the processing of emotion stimuli. Many relationships emerged for threatening emotions, indicating that high concentrations of testosterone, progesterone or cortisol, combined with poor sleep resulted in increased sensitivity towards threat detection. Together these studies provide evidence that hormones are an important factor in understanding the link between poor sleep and emotion functioning. Hormone concentration plays a role in understanding individual differences in response to sleep loss and can compound with sleep loss to result in worse emotional outcomes. Consideration of hormonal factors may help identify certain at-risk populations for sleep related deficits or timing of interventions.
  • Electrophysiological measures of flexible attentional control and visual working memory maintenance

    Salahub, Christine; Department of Psychology
    Top-down attentional control can be used to both guide attention toward and away from items according to their goal relevance. When given a feature-based cue, such as the colour of an upcoming target, individuals can allocate attention and memory resources according to the item’s priority. This distribution of resources is continuous, such that the amount that an item receives is dependent on its likelihood of being probed. However, top-down goals are often challenged by bottom-up stimulus salience of distractors. One’s ability to avoid attentional capture by distractors is limited by attentional control over bottom-up biases. In particular, individuals with anxiety have attentional biases toward both neutral and threatening distractors, leading to unnecessary storage of distractors in visual working memory (VWM). Using electrophysiology, it is possible to study the time course of these attentional processes to gain a better understanding of how attentional selection, suppression, and VWM maintenance relate to attentional control. The present thesis explores the event-related potential (ERP) correlates and time course of flexible attentional control, as well as how individual differences in anxiety limit this ability. In the first study, I used positive and negative feature-based cues to demonstrate that attentional selection occurs earlier when guided by target information than distractor information. Additionally, it was found that greater anxiety resulted in selection of the salient distractor, demonstrating that anxiety compromises early attentional control. For the second study, I further examined deficits in attentional control in anxiety. Here, it was demonstrated that individuals with high anxiety had early selection of threat-related distractors, whereas individuals with low anxiety could pro-actively suppress them. Interestingly, this effect did not carry over to VWM maintenance, suggesting that deficits in early attentional control do not necessarily result in poor memory filtering. In the final study, I examined the link between continuous attentional allocation and VWM maintenance, finding that individuals use priority information to flexibly select and filter information from VWM. Together, in this thesis I propose that attentional control over selection, suppression, and VWM filtering processes is flexible, time-dependent, and driven both by external cues and internal biases related to individual differences in anxiety.
  • Distinct forms of depression and somatization following head injury: A neuropsychological framework and exploratory treatment paradigm for somatic symptoms and executive dysfunction following mild head injury

    Robb, Sean; Department of Psychology
    Psychiatric symptoms following traumatic brain injury (TBI) pose a significant barrier to neurorehabilitation and impact survivor’s life satisfaction following injury. Depressive and somatization symptoms are common clinical presentations postinjury; however, due to the paucity of etiological models to explain these symptoms, treatment approaches are predominately “borrowed” from non-neurally compromised populations with similar clinical presentations. The orbitofrontal cortex (OFC) is particularly vulnerable in TBI, and serves to modulate autonomic arousal states. Varying severities of TBI have been linked to autonomic underarousal as measured by electrodermal activation (EDA). In a series of studies examining persons with mild head injury (MHI), the phenomenological presentation of depressive and somatization symptoms was examined in persons with and without MHI, and the relationship between these symptoms and autonomic underarousal was explored. In study one, MHI were found to be autonomically underaroused, reporting more somatic depressive symptoms relative to their no-MHI cohort, and the relationship between their injury severity and the intensity of their somatic depressive complaints was completely mediated by underarousal. Investigating somatization revealed MHI status as a moderator of the relationship between somatization and post-concussive symptoms, with MHI having a stronger positive association. Autonomic underarousal was found to be a complete mediator between the relationship between injury severity and their somatization symptoms. In study two, we experimentally manipulated autonomic arousal through brief cardiovascular exercise and evaluated whether this concomitantly improved somatic-based psychiatric complaints and neurocognitive functioning in persons with MHI. Study two replicated the somatic depressive mediation model of study one, and revealed that the experimental manipulation was effective in increasing autonomic arousal, and improving somatic-psychiatric complaints and neurocognitive status. Collectively, these findings suggest that depressive and somatization symptoms postinjury are phenomenologically and etiologically different in persons with a history of head injury relative to their non-neurally compromised counterpart, and autonomic underarousal and OFC dysfunction is a strong candidate for continued investigation as an etiological model for psychiatric symptoms postinjury. Reversal of underarousal may serve as an important therapeutic goal. Lastly, we propose the term “somatic underarousal” to describe this symptomatology as a means to avoid confusion with the historical roots of the term somatization.
  • Testing a Hypothesis of Non-REM Sleep Reinforcement and REM Sleep Refinement for the Benefits of Post-Learning Sleep on Memory Retrieval

    MacDonald, Kevin John; Department of Psychology
    It is well established that post-learning sleep benefits later memory retrieval, but there is still much to learn about the processes involved and the nature of these benefits. Sleep is composed of stages of non-REM (NREM) and REM sleep: NREM sleep, especially slow wave activity of NREM sleep, and REM sleep have been implicated in memory performance benefits, but the specific contributions of each state remain unclear. This thesis presents a hypothesis proposing that post-learning NREM sleep supports memory accessibility, benefitting the likelihood of successful memory retrieval, and that post-learning REM sleep supports memory fidelity, allowing for more accurate retrieval when retrieval is successful. This hypothesis was tested over studies examining the effects of an afternoon nap (Chapter 2), targeted memory reactivation during NREM slow wave sleep (Chapter 3), and both targeted memory reactivation during NREM slow wave sleep and selective deprivation of REM sleep (Chapter 4) on measures of memory accessibility and memory fidelity in visuospatial memory tasks. In each study, measures of sleep architecture and electroencephalographic power in sleep were examined as predictors of memory performance. Several identified associations and interactions further inform an understanding of how NREM sleep and REM sleep may benefit memory performance. Most notably, these studies consistently found greater slow wave activity of NREM sleep to be specifically associated with better maintenance of memory accessibility. These studies did not identify a clear effect of REM sleep. It is hoped that the hypothesis and findings presented stimulate additional inquires that will further our understanding of the individual and combined contributions of NREM and REM sleep.
  • INHUMAN TARGETS: Psychopathy, Dehumanization, and Sexist and Violent Attitudes Towards Women

    Methot-Jones, Tabitha; Department of Psychology
    The current work presents three studies that examined the role of dehumanization in the association between psychopathy and sexist and violent attitudes towards women. This program had two overarching goals in examining psychopathy, dehumanization, and sexist and violent attitudes towards women. The first goal was to examine whether an indirect association between psychopathy and negative attitudes towards women existed through dehumanization. The second goal was to explore if, by introducing information that humanizes women, levels of dehumanization could be mitigated for individuals high on psychopathic traits. Employing mixed samples for both studies (student and community), Study 1 (n = 514) and Study 2 (n = 202) provided evidence that psychopathy demonstrated an indirect relationship with sexist and violent attitudes towards women via dehumanization. Study 2 also expanded on Study 1 by including a behavioural measure of violent attitudes towards women. Finally, Study 3 (n = 206), again using a mixed sample, attempted to manipulate dehumanization to see if it, and the sexist and violent attitudes associated with it, would be mitigated. Unfortunately, the manipulation failed, but we were able to use the data from Study 3 to provide a replication of the results of Study 2. Across three studies results suggested that the path from psychopathy to negative attitudes towards women was at least partially (if not fully) indirect through dehumanization. This suggests that dehumanization may be an important mechanism to consider when examining the tendency of individuals high in psychopathic traits to engage in violence towards women. Furthermore, because psychopathic traits are associated with violence perpetrated against women, dehumanization could be an important construct to consider when examining potential avenues for clinical interventions. Even more broadly, dehumanization could be an important construct for mitigating the association between psychopathy and violence generally.
  • Behavioural, Pharmacological, and Immunohistochemical Investigation of 50 kHz USVs as an Expression of Positive Emotional Arousal in the Long Evans Rat

    Mulvihill, Kevin; Department of Psychology
    The emission of ultrasonic vocalizations (USVs) in Rattus norvegicus is thought to effectively represent an underlying emotional state within the organism manifested at the behavioural level. The main goal of my thesis was to characterize, at multiple levels of analysis, the 50 kHz USVs of the adult rat as an overtly expressed form of positive emotional arousal. In chapter 2, I found evidence of individual differences in 50 kHz emission possibly reflective of a trait that does not merely overlap with approach motivation. The predisposition to emit 50 kHz USVs was found to provide additional information about the USV response to psychostimulant administration beyond approach motivation alone. In chapter 3, I found evidence that various social and non-social behavioural contexts appeared to exert influence on the frequency-modulation characteristics of 50 kHz USVs. My findings suggest that the highest rates of calling and frequency modulation inducible by non-pharmacological stimuli may be observed following exposure of a male rat to a naturally cycling female. Moreover, my research in chapter 3 established that despite context-specific modulation of 50 kHz USVs all such calling could be blocked by antagonism of dopamine receptors. In chapter 4, I utilized microinjections of dopamine into the shell of the nucleus accumbens to establish that dopamine is sufficient to induce 50 kHz USVs. Additionally, my findings from chapter 4 supported the observed association between frequency-modulated 50 kHz USVs and call rate typically induced by psychostimulants. In chapter 5, I used a minimal sensitization protocol with amphetamine to establish that 50 kHz USVs and measures of general ergometric activity could be dissociated. Additionally, in chapter 5 I attempted to find brain region activation patterns associated with calling. My chapter 5 findings failed to find any direct relations between immunostained brain regions and behavioural expression. However, exploratory analyses suggest possible associations between prefrontal and striatal regions may be involved in the USV behavioural response to amphetamine. In aggregate, my empirical findings are consistent with the existence of a putative subcomponent of the ascending mesolimbic dopamine system responsible for positive emotional arousal reflected by emission of 50 kHz USVs in the rat.
  • Dreams of the Deceased: Who Has Them and Why?

    Black, Joshua; Department of Psychology
    The limited research on dreams of the deceased is a cause for concern for those working with bereaved persons. This research addressed four questions: 1. Why do some bereaved individuals dream of the deceased while others do not? 2. Why are some dreams of the deceased a positive experience, while others are negative? 3. Are dreams of the deceased a form of continuing bond? 4. Are continuing bonds helpful for grief recovery? Four studies were conducted. In one, participants were 268 U.S. residents who had a romantic partner or spouse die in the prior 12 to 24 months. The second study had 199 U.S. residents whose dog or cat had died in the prior six months. The third study had 226 U.S. residents who experienced a stillbirth or miscarriage in the prior year. The fourth study had 218 participants, mostly U.S. residents, who had a romantic partner or spouse die in the prior 6 to 24 months. Participants completed all questionnaires online. Study 1 and 2 focused primarily on the issue of predicting the frequency of dreams of the deceased and found that frequency of general dream recall (all dreams, not just dreams of the deceased) was the primary predictor. In addition, grief intensity, openness to experience, and attachment security all showed indirect effects. All four studies, but especially studies 2 through 4, addressed the questions about the quality of dream experience, the relation of dreams of the deceased to continuing bonds, and the adaptiveness of continuing bonds. In general the findings from all four studies, but especially study 4, support the idea that there are multiple types of continuing bonds with differing impacts on grief recovery, and there are differing forms of dreams of the deceased, not all of which represent continuing bonds.
  • Patterns of Endocrine, Behavioural, and Neural Function Underlying Social Deficits after Social Instability Stress in Adolescent Rats

    Hodges, Travis; Department of Psychology
    Adolescence is a time of social learning as well as a period of heightened vulnerability to stressors and enhanced plasticity, compared with adulthood. Previous research found that repeated social instability stress (SS; daily isolation and return to an unfamiliar peer from postnatal day (PND) 30 - 45) administered in adolescent rats alters social function when tested in adulthood. The main goal of my thesis research was to characterize how SS in adolescent rats affects the development of social brain regions and social behaviour when tested soon after the procedure. In chapter 2, I found that SS potentiated corticosterone release in rats repeatedly paired with an unfamiliar cage-mate after isolation compared with rats that were paired with an unfamiliar cage-mate for the first time after isolation on PND 45. In chapter 3, I found that in social interaction tests (i.e., not in home cage), SS rats had lower social interactions despite having higher social approach with unfamiliar peers relative to control (CTL) rats. Social stimuli carried the same reward value for SS and CTL rats based on tests of conditioned place preference, and SS in adolescence impaired social recognition. Further, SS increased oxytocin receptor density in the nucleus accumbens and dorsal lateral septum in rats compared with CTL rats. In chapter 4, I found that the correlations between time spent in social interaction with an unfamiliar peer and Fos immunoreactivity (a marker of neural activity) in the arcuate nucleus, dorsal lateral septum, and posterior medial amygdala were in the opposite direction in SS rats to those in CTL rats. In chapter 5, I found differences in the expression of proteins relevant for synaptic plasticity and in dendritic arborisation in the lateral septum and medial amygdala. My findings of behavioural and neural differences between SS and CTL rats highlight the heightened vulnerability of the brain to the quality of social experiences during the adolescent period that may lead to long-lasting deficits in social function in adulthood.
  • Cognitive Dissonance, Hypocrisy, and Reducing Toleration of Human Rights Violations

    Drolet, Caroline; Department of Psychology
    Despite documents such as the United Nations’ Universal Declaration of Human Rights, people still tolerate human rights violations. My dissertation examined possible methods for reducing this toleration. Specifically, I used “hypocrisy induction” to try and reduce toleration of rights violations and encourage pro-human rights responses. Hypocrisy induction—a procedure based on cognitive dissonance—involves having people recognize that their responses in a given situation are at odds with a strongly held attitude. In Study 1, I examined whether people who support human rights would reduce their toleration of a rights violation when confronted with their previous hypocritical toleration. Although participants who were confronted with their hypocrisy were more willing to act to promote human rights, they did not reduce their toleration of a violation, contrary to expectations. One reason for the lack of change in toleration could be that personal toleration of a human rights violation is not directly related to the occurrence of violations. Thus, for Studies 2 and 3, I extended the hypocrisy induction procedure to a case where an ingroup member’s hypocrisy directly resulted in a human rights violation. Specifically, I examined whether Canadians would alter their own toleration of a violation in response to a Canadian official who permitted a human rights violation. Results from both studies indicated that the group-level procedure was effective at encouraging pro-human rights responses, but not at reducing toleration of a violation. Moreover, results from Study 3 indicated that the effect of the group-level procedure was the result of directly-experienced, not vicarious, discomfort. I refer to the dissonance associated with the former type of discomfort as “group-level” dissonance. Although hypocrisy induction was not useful for reducing the toleration of human rights violations, my results suggest that both the group- and individual-level procedures can be used to encourage other pro-human rights responses.

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