• Affective Traits of Psychopathy and the Role of Early Visual Attention: An Electrophysiological Study

      Weissflog, Meghan; Department of Psychology
      Models of affective processing abnormalities in psychopathy have involved both amygdala abnormalities and attentional deficits to peripheral affective information. Neurophysiological bases for the latter are not currently well understood. Often presented as competing explanations for affective traits of psychopathy, these models may instead be compatible, describing different levels of analysis, with the amygdala playing a role in early attention allocation. To explore this possibility, this dissertation was designed to integrate these two areas of the literature by proposing a neurophysiologically-based model of biases in attention to peripheral affective information in psychopathy. This model is centred on the idea that attentional biases seen in psychopathy may result from reduced responsivity of a subcortical thalamus-amygdala circuit that influences the allocation of attention to salient stimuli in the environment during initial stages of processing. Event-related potential (ERP) components that reflect attention allocation during early stages of visual information processing were used to test the hypothesis that individuals high in psychopathic traits would show reduced attention allocation to peripheral information in the form of reduced and/or delayed ERP responses. Explored were the relations between psychopathic personality traits and early ERP responses to simple stimulation of the visual system (Study 1) and to spatially-filtered emotional faces involving implicit versus explicit processing of the stimuli (Study 2). ERP effects related to overall psychopathic trait severity, but also yielded factor-specific ERP response patterns. Study 1 results were consistent with the present hypotheses. Specifically, higher Factor 1 scores (primary, affect-based traits) were associated with reduced attention-related ERP amplitudes in response to a flash stimulus presented peripheral to task performance. Factor 2 severity (secondary antisocial and behavioural traits) was associated with ERP latencies in primary visual cortex. Study 2 also showed somewhat more complex but Factor-specific patterns of early visual processing. Overall, the results were consistent with a reduced responsivity of the thalamo-amygdalar pathway in psychopathy-related individual differences in attention at early stages of visual information processing, both for affective information and simple sensory stimulation. This raises the question of whether such processing differences are a predisposing factor for the development of psychopathic traits.
    • Affinity for Aloneness and Shyness in Childhood and Adolescence: Differential Longitudinal Associations with Socio-emotional Adjustment

      Shapira, Marina; Department of Psychology
      Affinity for aloneness (AFA), a tendency to prefer to spend more time alone rather than with others, is assumed to be driven by low social interest rather than by social fears. This is unlike shyness, which is underpinned by a conflict between high social interest and pervasive social apprehension and weariness. Despite the marked motivational differences between these two subtypes of social withdrawal and their potential differential impact on socio-emotional adjustment in childhood and adolescence, AFA is empirically neglected compared to shyness. Shyness was extensively studied and repeatedly linked to a host of negative socio-emotional correlates such as depression, lower social skills, lower self-esteem and peer maltreatment. However, little is known about the socio-emotional impact of AFA on children and adolescents, particularly longitudinally. Despite clear evidence, AFA was suspected as maladaptive due to its affiliation with social withdrawal, a wide umbrella term that has been tied to internalizing problem and peer difficulties. The generalization of findings regarding social withdrawal as a whole to AFA may lead to a pathologization of a normative behavior, increase instances of unnecessary intervention, and inadvertently negatively impact otherwise intact socio-emotional development of children and adolescents. The scarce available knowledge about AFA stems from several persisting gaps in the literature. First, there is insufficient systematic differentiation among subtypes of social withdrawal, and a lack of deliberate simultaneous measurement of specific constructs such as shyness and AFA. Second, there are very few longitudinal studies of both shyness and AFA across childhood and adolescence. Third, there is a lack of contextual investigation of AFA compared to shyness in common life setting in which children tend to spend much of their time, such as organized sports activities. My doctoral dissertation specifically addressed all of the aforementioned gaps in the literature. Results of Study 1, a longitudinal study spanning from Grade 3 to Grade 5, indicated that only shyness, but not AFA, was significantly related to lower social skills and greater peer victimization across time. Study 2 utilized Latent Class Analysis and results indicated that adolescents in Grades 11 and 12 who were high on AFA and low on shyness did not differ from adolescents low on both AFA and shyness (a non-withdrawn group) on measures of socio-emotional adjustment. In Study 3, results of Structural Equation Modeling (SEM) indicated that only shyness, but not AFA, was related to lower positive activity outcomes through lower psychological engagement in the activity. In aggregate, the findings of the present doctoral studies advance the literature on AFA in meaningful ways. Most notably, AFA emerged as a largely benign form of social withdrawal across middle childhood and adolescence. Moreover, Study 2, which appears to be the first person-centered investigation of AFA in adolescence using Latent Class Analysis, provided novel evidence that AFA and shyness are distinct constructs with unique implication for socio-emotional adjustment. These findings carry applied implication for educators and parents seeking to facilitate optimal developmental contexts for children with an AFA.
    • An after-school literacy program : investigating the experiences of students with literacy difficulties, their volunteer tutors, and the tutors' transition into the teaching profession

      Gallagher, Tiffany L.; Department of Psychology (Brock University, 2005-05-28)
      This research responds to a pervasive call for our educational institutions to provide students with literacy skills, and teachers with the instructional supports necessary to facilitate this skill acquisition. Questions were posed to gain information concerning the efficacy ofteaching literacy strategies to students with learning difficulties, the impact of this training on their volunteer tutors, and the influence of this experience on these tutors' ensuing instructional practice as teacher candidates in a preservice education program. Study #1 compared a nontreatment group of students with literacy difficulties who participated in the program and found that program participants were superior at reading letter patterns and at comprehending the elements of story grammar. Concurrently, the second study explored the experiences of 19 volunteer tutors and uncovered that they acquired instructional skills as they established a knowledge base in teaching reading and writing, and they affirmed personal goals to become future teachers. Study #3 tracked 6 volunteer tutors into their pre-service year and identified their constructions, and beliefs about literacy instruction. These teacher candidates discussed how they had intended to teach reading and writing strategies based on their position that effective teaching ofthese skills in the primary grades is integral to academic success. The teacher candidates emphasized the need to build rapport with students, and the need to exercise flexibility in lesson plan delivery while including activities to meet emotional and developmental requirements of students. The teacher candidates entered their pre-service education with an initial cognition set based on the limited teaching context of tutoring. This foundational ii perception represented their prior knowledge of literacy instruction, a perception that appeared untenable once they were immersed in a regular instructional setting. This disparity provoked some of the teacher candidates to denounce their teacher mentors for not consistently employing literacy strategies and individualized instruction. This critical perspective could have been a demonstration of cognitive dissonance. In the end, when the teacher candidates began to look toward the future and how they would manage the demands of an inclusive classroom, they recognized the differences in the contexts. With an appreciation for the need for balance between prior and present knowledge, the teacher candidates remained committed to implementing their tutoring strategies in future teaching positions. This document highlights the need for teacher candidates with instructional experience prior to teacher education, to engage in cognitive negotiations to assimilate newly acquired pedagogies into existing pedagogies.
    • The Associations Among Sleep Problems, Emotion Dysregulation and Adjustment Over Time Among University Students

      Semplonius, Thalia; Department of Psychology
      Young adults experience a variety of changes when entering university (e.g., leaving home for the first time). Although some students adjust well to university, others may experience difficulties. Two problems that may be experienced are sleep problems and difficulties regulating emotion; importantly, both of these factors are associated with a variety of adjustment indicators. Throughout this dissertation, the three adjustment indicators that were of interest were physical activity, depressive symptoms and alcohol use as all three are common throughout university. As little work has examined the direction of effects between all of these factors, a longitudinal dataset was used to examine the relationships among these factors in two ways. Participants included 1132 first year undergraduate students (Time 1 Mage = 19.06 years, SD = 11.17 months). The first method was the use of a variable-centered analysis which was used in Studies 1 and 2. Study 1 focused on the relationships among sleep problems, emotion dysregulation, and physical activity and Study 2 focused on the relationships among sleep problems, emotion dysregulation, depressive symptoms, and alcohol use. Study 3 used a person-centered analysis which allowed for the examination of heterogeneity in the patterns of association between variables. Specifically, this study involved examining heterogeneity in the associations between sleep problems and emotion dysregulation, and how these patterns were related to depressive symptoms and alcohol use in both the short- and longterm. Overall, these studies indicate that sleep and emotion dysregulation are both bidirectionally related over time and also co-occur for a subgroup of individuals. The results also indicate that difficulties in adjustment experienced early on in university may have lasting effects.
    • Attention capture: Stimulus, group, individual, and moment-to-moment factors contributing to distraction

      Stokes, Kirk; Department of Psychology
      Over four studies, some containing multiple experiments, attention capture is explored in a variety of experimental contexts. The over-arching goals were to better understand attention capture at the stimulus level (Chapter 2), the group and the individual-differences level (Chapters 3 and 4), and in terms of moment-to-moment fluctuations in susceptibility to distraction by task-irrelevant stimuli (Chapter 5). Rare or unexpected stimulus changes are known to capture attention and disrupt behavioural performance. Detection is typically thought to depend on changes to the physical properties (e.g., tone pitch) of a stimulus. Chapter 2 explores whether physical change is a necessary antecedent for attention capture. Here, evidence suggests that unexpected semantic change is sufficient to produce a distraction effect and that an accompanying physical/acoustic change is not required to induce semantic processing of task-irrelevant stimuli even when the semantic deviants are unrelated to the primary task. Attention capture is typically robust at the group level and has been observed in a variety of popular paradigms. Chapter 3 explores whether attention capture can be viewed as a stable and generalizable individual trait. The study examined involuntary attention capture across a set of prototypical stimulus-driven capture tasks and contingent-capture tasks in both spatial and/or temporal paradigms. Results showed the expected pattern of capture in each of the tasks as well as modest to good test-retest reliability over the span of one week for each of the capture measures. However, no evidence is found for a common attention capture factor providing evidence that attention capture within an individual is reliable but not generalizable. Chapter 4 extends the results of Chapter 3 and shows that attention capture in these tasks is not related to off-line self-report measures of attentional ability and day-to-day functioning. The lack of evidence for a common factor that can predict attention capture in one or more paradigms suggests that attention capture is not characterized by trait individual differences in executive function or predicted by individuals’ meta-awareness of their own attentional ability. Chapter 5, however, shows that attention capture can be characterized by moment-to-moment lapses of attention as it varies trial-to-trial as a function of internally generated task-irrelevant thought (i.e., mind-wandering). Mind-wandering slowed RTs overall and increased non-contingent, but not contingent, forms of capture providing evidence that some forms of attention capture are exacerbated by moment-to-moment lapses of attention. Self-reports on a dispositional mind-wandering scale did not predict capture when mind-wandering was used as an individual differences variable. Results suggest that attention capture may be better explained by cognitive processes engaged moment-to-moment rather than individual dispositions.
    • Autonomic and electrocortical indices of performance monitoring and source memory discrimination in older and younger adults

      Mathewson, Karen Janet.; Department of Psychology (Brock University, 2009-05-28)
      Reduced capacity for executive cognitive function and for the autonomic control of cardiac responsivity are both concomitants of the aging process. These may be linked through their mutual dependence on medial prefrontal function, but the specifics ofthat linkage have not been well explored. Executive functions associated with medial prefrontal cortex involve various aspects ofperformance monitoring, whereas centrally mediated autonomic functions can be observed as heart rate variability (HRV), i.e., variability in the length of intervals between heart beats. The focus for this thesis was to examine the degree to which the capacity for phasic autonomic adjustments to heart rate relates to performance monitoring in younger and older adults, using measures of electrocortical and autonomic activity. Behavioural performance and attention allocation during two age-sensitive tasks could be predicted by various aspects of autonomic control. For young adults, greater influence of the parasympathetic system on HRV was beneficial for learning unfamiliar maze paths; for older adults, greater sympathetic influence was detrimental to these functions. Further, these relationships were primarily evoked when the task required the construction and use of internalized representations of mazes rather than passive responses to feedback. When memory for source was required, older adults made three times as many source errors as young adults. However, greater parasympathetic influence on HRV in the older group was conducive to avoiding source errors and to reduced electrocortical responses to irrelevant information. Higher sympathetic predominance, in contrast, was associated with higher rates of source error and greater electrocortical responses tq non-target information in both groups. These relations were not seen for 11 errors associated with a speeded perceptual task, irrespective of its difficulty level. Overall, autonomic modulation of cardiac activity was associated with higher levels of performance monitoring, but differentially across tasks and age groups. With respect to age, those older adults who had maintained higher levels of autonomic cardiac regulation appeared to have also maintained higher levels of executive control over task performance.
    • Autonomic and Electrophysiological Correlates of Cognitive Control in Aging

      Capuana, Lesley; Department of Psychology (Brock University, 2014-08-21)
      This thesis tested a model of neurovisceral integration (Thayer & Lane, 2001) wherein parasympathetic autonomic regulation is considered to play a central role in cognitive control. We asked whether respiratory sinus arrhythmia (RSA), a parasympathetic index, and cardiac workload (rate pressure product, RPP) would influence cognition and whether this would change with age. Cognitive control was measured behaviourally and electrophysiologically through the error-related negativity (ERN) and error positivity (Pe). The ERN and Pe are thought to be generated by the anterior cingulate cortex (ACC), a region involved in regulating cognitive and autonomic control and susceptible to age-related change. In Study 1, older and younger adults completed a working memory Go/NoGo task. Although RSA did not relate to performance, higher pre-task RPP was associated with poorer NoGo performance among older adults. Relations between ERN/Pe and accuracy were indirect and more evident in younger adults. Thus, Study 1 supported the link between cognition and autonomic activity, specifically, cardiac workload in older adults. In Study 2, we included younger adults and manipulated a Stroop task to clarify conditions under which associations between RSA and performance will likely emerge. We varied task parameters to allow for proactive versus reactive strategies, and motivation was increased via financial incentive. Pre-task RSA predicted accuracy when response contingencies required maintenance of a specific item in memory. Thus, RSA was most relevant when performance required proactive control, a metabolically costly strategy that would presumably be more reliant on autonomic flexibility. In Study 3, we included older adults and examined RSA and proactive control in an additive factors framework. We maintained the incentive and measured fitness. Higher pre-task RSA among older adults was associated with greater accuracy when proactive control was needed most. Conversely, performance of young women was consistently associated with fitness. Relations between ERN/Pe and accuracy were modest; however, isolating ACC activity via independent component analysis allowed for more associations with accuracy to emerge in younger adults. Thus, performance in both groups appeared to be differentially dependent on RSA and ACC activation. Altogether, these data are consistent with a neurovisceral integration model in the context of cognitive control.
    • Autonomy and Relatedness in Mainland Chinese Adolescents: Social or Personal? Accommodation or Distinctiveness?

      Zhao, Junru; Department of Psychology (Brock University, 2014-08-01)
      Three studies comprised the current research program, in which the major goals were to propose and validate empirically the proposed two-level (universal and culture-specific) model of both autonomy and relatedness, as well as to develop reliable and valid measures for these two constructs. In Study 1, 143 mainland Chinese adolescents were asked open-ended questions about their understanding of autonomy and relatedness in three social contexts (peer, family, school). Chinese youth’s responses captured universal and culturally distinctive forms of autonomy (personal vs. social) and relatedness (accommodation vs. distinctiveness), according to a priori criteria based on the theoretical frameworks. Also, scenarios designed to reflect culture-specific forms of autonomy and relatedness suggested their relevance to Chinese adolescents. With a second sample of 201 mainland Chinese youth, in Study 2, the obtained autonomy and relatedness descriptors were formulated into scale items. Those items were subject to refinement analyses to examine their psychometric properties and centrality to Chinese youth. The findings of Study 1 scenarios were replicated in Study 2. The primary goal of Study 3 was to test empirically the proposed two-level (universal and culture-specific) models of both autonomy and relatedness, using the measures derived from Studies 1 and 2. A third sample of 465 mainland Chinese youth completed a questionnaire booklet consisting of autonomy and relatedness scales and scenarios and achievement motivation orientations measures. A series of confirmatory factor analysis (CFA) autonomy and relatedness measurement models (first-order and second-order), as well as structural models linking culture-specific forms of autonomy and relatedness and achievement motivation orientations, were conducted. The first-order measurement models based on scale and scenario scores consistently confirmed the distinction between personal autonomy and social autonomy, and that of accommodation and distinctiveness. Although the construct validity of the two culture-specific forms of autonomy gained additional support from the structural models, the associations between the two culture-specific forms of relatedness and achievement motivation orientations were relatively weak. In general, the two-level models of autonomy and relatedness were supported in two ways: conceptual analysis of scale items and second-order measurement models. In addition, across the three studies, I explored potential contextual and sex differences in Chinese youth’s endorsement of the diverse forms of autonomy and relatedness. Overall, no substantial contextual variability or sex differences were found. The current research makes an important theoretical contribution to the field of developmental psychology in general, and autonomy and relatedness in particular, by proposing and testing empirically both universal and culture-specific parts of autonomy and relatedness. The current findings have implications for the measurement of autonomy and relatedness across social contexts, as well as for socialization and education practice.
    • 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.
    • 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.
    • A comprehensive examination of adolescent gambling

      Chalmers, Heather.; Department of Psychology (Brock University, 2004-05-28)
      The purposes of this study were: a) to examine the prevalence and consequences associated with adolescent gambling, b) to examine the factors which influence adolescent gambling,. c) to detennine what factors discriminate among four groups of gamblers (no-risk/non-gamblers, low-risk gamblers, at-risk gamblers, and high-risk/problematic gamblers), and d) to examine the relation of gambling to nine other risk behaviours (i.e., alcohol use, smoking, marijuana use, hard drug use, sexual activity, minor delinquency, major delinquency, direct aggression, and indirect aggression). Adolescents (N = 3,767) from 25 secondary schools completed a twohour survey that assessed involvement in risk be~aviours as well as potential predictors from a wide range of contexts (school, neighbourhood, family, peer, and intrapersonal). The majority of adolescents reported gambling, although the frequency of gambling participation was low. The strongest predictors/discriminators of gambling involvement were gender, unstructured activities, structured activities, and risk attitudes/perceptions. In addition, the examination of the co-occurrence of gambling with other risk behaviours revealed that for high-risk/problem gamblers, the top three most frequent co-occurring high-risk behaviours were direct aggression, minor delinquency and alcohol. This study was the first to examine the continuum of gambling involvement (i.e., non-gambling to high risk/problematic gambling) using a comprehensive set ofpotential predictors with a large sample of secondary school students. The findings of this study support past research and theories (e.g., Theory of Triadic Influence) which suggest the importance ofproximal variables in predicting risk behaviors. The next step, however, will be to examine the direct and indirect 1 effects of the ultimate (e.g., temperament), distal (e.g., parental relationship), and proximal variables (e.g., risk attitudes/perceptions) on gambling involvement in a longitudinal study.
    • Creativity and the schizophrenia spectrum unveiled : the similarities and the differences

      Michalica, Kerri; Department of Psychology (Brock University, 2010-10-27)
      This study examined the commonalities and the differences between creativity and the schizophrenia spectrum. The variables measured as potential commonalities and differences were creativity, schizotypy, cognitive inhibition, spatial ability, balancing skills, positive and negative presence, absorption, mystical experiences, childhood abuse, and neuroticism. Three community groups were recruited, consisting of 31 artists, 10 people with schizophrenia, and 31 comparisons matched for gender and age with the artists. A larger student group consisting of 102 students was also recruited in order to examine the correlations among the same variables within a larger, more normative, group. The largest commonality between the artist and the schizophrenic groups, who represented the extreme end of the schizophrenia spectrum, was the propensity to mystical experiences. The greatest differences between the artist and the schizophrenic groups were that the artists were higher in creativity, performed better on spatial abilities, had better balance, had more positive states of presence, and were lower in neuroticism than the schizophrenic group. In the student group, creativity was correlated with spatial ability, positive presence, absorption, and mystical experiences. In addition, creativity was significantly related to two facets of schizotypy, unusual experiences and impulsive nonconformity. In other words, students high in certain facets of schizotypy, who may share certain characteristics with those who have schizophrenia, are higher in creativity, but people who are on the extreme end of the schizophrenia spectrum, who have been diagnosed with schizophrenia, are not. The differences between the artist and schizophrenic groups on spatial ability, balance, sense of presence, and neuroticism may help to determine whether mystical experiences help to integrate creative work or destabilize and disorganize the sense of self. It may be that mystical experiences can be used more positively by the creative individuals than people with schizophrenia, in that artists and people high in creativity were higher in positive traits such as positive presence and lower on negative variables such as neuroticism, and introvertive anhedonia.
    • Demolishing the Competition: The Association between Competitive Video Game Play and Aggression among Adolescents and Young Adults

      Adachi, Paul; Department of Psychology
      The link between video game play and aggression is an important issue as video games The link between video game play and aggression is an important issue as video games are the fastest growing form of entertainment in the world. Past research on this association has been focused primarily on the link between video game violence and aggression; however, this research has confounded the effect of video game violence versus competition on aggression. The main goal of the current dissertation, therefore, was to examine the short- and long-term associations between competitive video game play and aggression. In addition, the longitudinal work on this association to date has been limited to adolescent samples, but not young adults. Thus, the second goal of the dissertation research was to investigate whether video game play predicts aggression in the long-term among young adults in addition to adolescents. To address these goals, three studies were conducted. Study 1 consisted of a series of experiments examining the short-term effect of video game violence versus competition on aggression. Study 2 examined the long-term association between competitive video game play and aggression among adolescents, and Study 3 examined this long-term link among young adults, in addition to adolescents. Taken together, the results of the three dissertation studies converged to suggest that video game competition, rather than violence, may be a stronger predictor of aggression in both the short- and long-term. Overall, the current research represents an important advance in our understanding of the association between video game play and aggression, and leads to a new direction in the video game and aggression literature. are the fastest growing form of entertainment in the world. Past research on this association has been focused primarily on the link between video game violence and aggression; however, this research has confounded the effect of video game violence versus competition on aggression. The main goal of the current dissertation, therefore, was to examine the short- and long-term associations between competitive video game play and aggression. In addition, the longitudinal work on this association to date has been limited to adolescent samples, but not young adults. Thus, the second goal of the dissertation research was to investigate whether video game play predicts aggression in the long-term among young adults in addition to adolescents. To address these goals, three studies were conducted. Study 1 consisted of a series of experiments examining the short-term effect of video game violence versus competition on aggression. Study 2 examined the long-term association between competitive video game play and aggression among adolescents, and Study 3 examined this long-term link among young adults, in addition to adolescents. Taken together, the results of the three dissertation studies converged to suggest that video game competition, rather than violence, may be a stronger predictor of aggression in both the short- and long-term. Overall, the current research represents an important advance in our understanding of the association between video game play and aggression, and leads to a new direction in the video game and aggression literature.
    • Determinants and Consequences of Dehumanization: An Interspecies Model of Prejudice

      Costello, Kimberly; Department of Psychology (Brock University, 2013-01-14)
      Dehumanizing ideologies that explicitly liken other humans to “inferior” animals can have negative consequences for intergroup attitudes and relations. Surprisingly, very little is known about the causes of dehumanization, and essentially no research has examined strategies for reducing dehumanizing tendencies. The Interspecies Model of Prejudice specifies that animalistic dehumanization may be rooted in basic hierarchical beliefs regarding human superiority over animals. This theoretical reasoning suggests that narrowing the human-animal divide should also reduce dehumanization. The purpose of the present dissertation, therefore, was to gain a more complete understanding of the predictors of and solutions to dehumanization by examining the Interspecies Model of Prejudice, first from a layperson’s perspective and then among young children. In Study 1, laypeople strongly rejected the human-animal divide as a probable cause of, or solution to, dehumanization, despite evidence that their own personal beliefs in the human-animal divide positively predicted their dehumanization (and prejudice) scores. From Study 1, it was concluded that the human-animal divide, despite being a robust empirical predictor of dehumanization, is largely unrecognized as a probable cause of, or solution to, dehumanization by non-experts in the psychology of prejudice. Studies 2 and 3 explored the expression of dehumanization, as well as the Interspecies Model of Prejudice, among children ages six to ten years (Studies 2 and 3) and parents (Study 3). Across both studies, White children showed evidence of racial dehumanization by attributing a Black child target fewer “uniquely human” characteristics than the White child target, representing the first systematic evidence of racial dehumanization among children. In Study 3, path analyses supported the Interspecies Model of Prejudice among children. Specifically, children’s beliefs in the human-animal divide predicted greater racial prejudice, an effect explained by heightened racial dehumanization. Moreover, parents’ Social Dominance Orientation (preference for social hierarchy and inequality) positively predicted children’s human-animal divide beliefs. Critically, these effects remained significant even after controlling for established predictors of child-prejudice (i.e., parent prejudice, authoritarian parenting, and social-cognitive skills) and relevant child demographics (i.e., age and sex). Similar patterns emerged among parent participants, further supporting the Interspecies Model of Prejudice. Encouragingly, children reported narrower human-animal divide perceptions after being exposed to an experimental prime (versus control) that highlighted the similarities among humans and animals. Together the three studies reported in this dissertation offer important and novel contributions to the dehumanization and prejudice literature. Not only did we find the first systematic evidence of racial dehumanization among children, we established the human-animal divide as a meaningful dehumanization precursor. Moreover, empirical support was obtained for the Interspecies Model of Prejudice among diverse samples including university students (Study 1), children (Studies 2 and 3), and adult-aged samples (Study 3). Importantly, each study also highlights the promising social implication of targeting the human-animal divide in interventions to reduce dehumanization and other prejudicial processes.
    • Developmental and gonadal regulation of hypothalamic-pituitary-adrenal axis function in adolescent and adult rats

      Green, Matthew; Department of Psychology
      The hypothalamic-pituitary-adrenal (HPA) axis regulates the release of stress hormones and its function is dependent on various factors including prior exposure to stressors, circulating gonadal hormones, and developmental status. The overarching goal of this thesis was to uncover the potential mechanisms mediating developmental changes in HPA function and its regulation by gonadal hormones during adolescence and early adulthood. In Chapter 2, I found that pre-pubertal (postnatal day [P]35) and post-pubertal (P45) adolescents responded to an acute stressor with greater release of corticosterone (the main stress hormone in rodents) compared with adults (P75). To determine whether differences in corticosterone release were related to ongoing maturation of HPA feedback, I investigated glucocorticoid receptor (GR) activity and mRNA expression of receptors (Nr3c1, Nr3c2) and their co-chaperones (Fkbp5, Fkbp4, Bag1) in the hippocampus. I provide novel evidence that P35 males have more, not less, GR translocation from the cytosol to the nucleus in response to stress compared with P75 males. Gene expression remained relatively stable across development, except for Fkbp4, which codes for a pro-translocation protein and was up-regulated in P35 males relative to expression in P75 males. Thus, there are developmental shifts in the hormonal response to stress that are likely unrelated to GR activity in the hippocampus. In Chapter 3, I investigated whether differences in HPA function are explained by gonadal status; in adult males, testosterone reduces HPA function. Age-related differences in corticosterone release persisted when orchiectomized (OCX) males at each age were administered testosterone. Moreover, the effect of testosterone changed across the adolescent period; relative to those that got blank implants, testosterone had no effect on post-stress concentrations of corticosterone at P35, increased concentrations at P45, and tended to reduce concentrations at P75. Testosterone reduced expression of AVP in the PVN at all ages, but did not affect Fos (a marker of neuronal activation) expression. I hypothesized that the age-specific effects of testosterone on corticosterone were related to differential conversion to metabolites (e.g., estradiol), which I tested using androgen receptor (AR) and estrogen receptor (ER) antagonists (flutamide and tamoxifen, respectively) in the presence of testosterone or dihydrotestosterone (DHT). Testosterone produced a similar, albeit non-significant, age-specific pattern of effects on corticosterone as described above, and I found little evidence for effects of receptor antagonists. Androgens reduced post-stress concentrations of progesterone in all age groups, and flutamide prevented the effect. Together, this study provides evidence for developmental shifts in stress responses and their regulation by gonadal hormones. In Chapter 4, I examined the influence of estradiol on HPA function in adult female rats as a first step toward understanding developmental shifts. Ovariectomy (OVX) reduced post-stress concentrations of corticosterone compared with sham OVX and OVX females given estradiol alone or in combination with progesterone. I also found that OVX females had greater cytosolic expression of GR, possibly increasing sensitivity to corticosterone. In a second experiment, I found that progesterone partially mitigated the effect of estradiol on corticosterone release and that gene expression of stress hormone receptors (Nr3c1, Nr3c2), their co-chaperones (Fkbp5, Fkbp4, Bag1), and a co-activator (Src-1) did not change as a function of ovarian hormones. Together, these studies build on previous research investigating developmental and gonadal regulation of HPA activity and provide novel findings regarding potential mechanisms underlying their actions.
    • Developmental differences in locomotor responsiveness to amphetamine in rats

      Mathews, Iva; Department of Psychology (Brock University, 2011-10-14)
      The developmental remodelling of motivational systems that underlie drug dependence and addiction may account for the greater frequency and severity of drug abuse in adolescence compared to adulthood. Recent advances in animal models have begun to identify the morphological and the molecular factors that are being remodelled, but little is known about the culmination of these factors in altered sensitivity to psycho stimulant drugs, like amphetamine, in adolescence. Amphetamine induces potent locomotor activating effects in rodents through increased dopamine release in the mesocorticolimbic dopamine system, which makes locomotor activity a useful behavioural marker of age differences in amphetamine sensitivity. The aim of the thesis was to investigate the neural basis for age differences in amphetamine sensitivity with a focus on the nucleus accumbens and the medial prefrontal cortex, which initiate and regulate amphetamine-induced locomotor activity, respectively. In study 1, I found pre- and post- pubertal adolescent rats to be less active (i.e., hypoactive) than adults to a first injection of 0.5, but not of 1.5, mg/kg of intraperitonealy (i.p.) administered amphetamine. Although initially hypoactive, only adolescent rats exhibited an increase in activity to a second injection of amphetamine given 24 h later, indicating that adolescents may be more sensitive to the rapid changes in amphetamineinduced plasticity than adults. Given that the locomotor activating effects of amphetamine are initiated in the nucleus accumbens, age differences in response to direct injections of amphetamine into this brain region were investigated in study 2. In contrast to i.p. injections, adolescents were more active than adults when amphetamine was given directly into the nucleus accumbens, indicating that hypo activity may be attributed to the development of regulatory regions outside of the accumbens. The medial prefrontal cortex (mPFC) is a key regulator of the locomotor activating effects of amphetamine that undergoes extensive remodelling in adolescence. In study 3, I found that an i.p. injection of 1.5, and not of 0.5, mg/kg of amphetamine resulted in a high expression of c-fos, a marker of neural activation, in the pre limbic mPFC only in pre-pubertal adolescent rats. This finding suggests that the ability of adolescent rats to overcome hypo activity at the 1.5 mg/kg dose may involve greater activation of the prelimbic mPFC compared to adulthood. In support of this hypothesis, I found that pharmacological inhibition of prelimbic D 1 dopamine receptors disrupted the locomotor activating effects of the 1.5 mg/kg dose of amphetamine to a greater extent in adolescent than in adult rats. In addition, the stimulation of prelimbic D 1 dopamine receptors potentiated locomotor activity at the 0.5 mg/kg dose of amphetamine only in adolescent rats, indicating that the prelimbic D1 dopamine receptors are involved in overcoming locomotor hypoactivity during adolescence. Given my finding that the locomotor activating effects of amphetamine rely on slightly different mechanisms in adolescence than in adulthood, study 4 was designed to determine whether the lasting consequences of drug use would also differ with age. A short period of pre-treatment with 0.5 mg/kg of amphetamine in adolescence, but not in adulthood, resulted in heightened sensitivity to an injection of amphetamine given 30 days after the start of the procedure, when adolescent rats had reached adulthood. The finding of an age-specific increase in amphetamine sensitivity is consistent with evidence for increased risk for addiction when drug use is initiated in adolescence compared to adulthood in people (Merline et aI., 2002), and with the hypothesis that adolescence is a sensitive period of development.
    • Dispositional Forgiveness and Health in Romantic Relationships: An Exploration of Sex Differences, Actor Effects, and Partner Effects

      Green, Michelle; Department of Psychology (2012-07-30)
      The individual and dyadic associations between dispositional forgiveness of self, others, and situations and mental and physical health in individuals involved in romantic relationships were examined. Sex differences in the relationship between dispositional forgiveness and health were examined. Sex differences in the dyadic relationship between forgiveness and health were also examined. The dispositional forgiveness scores of 297 partners involved in a romantic relationship were used to predict their own as well as their partners' physical and mental health. Both members of the relationship separately completed an Internet-based questionnaire assessing personality traits, relationship variables, and physical and mental health. The couple was provided with monetary compensation. Analyses revealed that women's dispositional forgiveness of self, others, and situations were positively associated with their own physical and mental health. Similarly, men's dispositional forgiveness of self, others, and situations were positively associated with their own mental and physical health. At the individual level, there were no sex differences in the relationship between dispositional forgiveness and health, nor were there sex differences in men and women's reports of dispositional forgiveness. Analyses revealed that men's forgiveness of others and situations were positively associated with their female partners' mental health. There were no partner effects for women or for physical health. The implications of these results for research in the forgiveness-health literature and research on forgiveness in romantic relationships were discussed as were directions for future research.
    • 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.
    • A domain-general perspective on medial frontal brain activity during performance monitoring

      van Noordt, Stefon; Department of Psychology
      Activity of the medial frontal cortex (MFC) has been implicated in attention regulation and performance monitoring. The MFC is thought to generate several event-related potential (ERPs) components, known as medial frontal negativities (MFNs), that are elicited when a behavioural response becomes difficult to control (e.g., following an error or shifting from a frequently executed response). The functional significance of MFNs has traditionally been interpreted in the context of the paradigm used to elicit a specific response, such as errors. In a series of studies, we consider the functional similarity of multiple MFC brain responses by designing novel performance monitoring tasks and exploiting advanced methods for electroencephalography (EEG) signal processing and robust estimation statistics for hypothesis testing. In study 1, we designed a response cueing task and used Independent Component Analysis (ICA) to show that the latent factors describing a MFN to stimuli that cued the potential need to inhibit a response on upcoming trials also accounted for medial frontal brain responses that occurred when individuals made a mistake or inhibited an incorrect response. It was also found that increases in theta occurred to each of these task events, and that the effects were evident at the group level and in single cases. In study 2, we replicated our method of classifying MFC activity to cues in our response task and showed again, using additional tasks, that error commission, response inhibition, and, to a lesser extent, the processing of performance feedback all elicited similar changes across MFNs and theta power. In the final study, we converted our response cueing paradigm into a saccade cueing task in order to examine the oscillatory dynamics of response preparation. We found that, compared to easy pro-saccades, successfully preparing a difficult anti-saccadic response was characterized by an increase in MFC theta and the suppression of posterior alpha power prior to executing the eye movement. These findings align with a large body of literature on performance monitoring and ERPs, and indicate that MFNs, along with their signature in theta power, reflects the general process of controlling attention and adapting behaviour without the need to induce error commission, the inhibition of responses, or the presentation of negative feedback.
    • 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.