• 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 (Brock University, 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.
    • Effective Police Interviewing

      Logue, Michael; Department of Psychology
      Suspect interviewing is a vital tool for law enforcement agencies. However, a large body of empirical literature has demonstrated that many interviewing techniques limit the amount of information gleaned and demonstrate chance levels of deception detection accuracy. The series of studies presented provide evidence that the application of Reality Monitoring (RM) to statements elicited by a modified version of the Cognitive Interview for Suspects (CIS) improves deception detection accuracy in comparison to levels previously reported in the literature. Study 1 considers deception detection accuracy in statements provided in a mock theft scenario. Participants were interviewed using a modified version of the CIS. Six RM criteria were applied to all statements as a measure of deception detection. This study found an overall accuracy rating of 86.6%, supporting the use of this protocol. Study 2 directly compares deception detection accuracy of RM to the subjective judgements of observers. Three hundred and ninety observers judged deceptiveness of 100 CIS interviews previously recorded in Study 1. Collectively the average level of accuracy for observer ratings of the first question of the CIS interviews was 52.73% and only 47.82% at the conclusion of the interview. Observer ratings of deception became significantly less accurate at the conclusion of the interview (t(389) = 4.75, p <.01). In contrast, the RM scale was highly accurate (92.5 %) in a direct comparison of the same interviews. Study 3 considers whether certain personality traits, namely psychopathy and social dominance, increase successful deception both in terms of observer ratings and Reality Monitoring. Findings indicate that social dominance was related to increased observer ratings of honesty over time, however socially dominant people were not particularly successful deceivers. Similarly, psychopathic traits were not significantly related to deceptive ability overall. However, Factor 2 psychopathy was linked to being less believable by observers, even when telling the truth. These personality traits were not linked to an increased ability to beat Reality Monitoring, providing further evidence for the use of this scale. Collectively, the studies presented provide evidence of the effectiveness of the use of Reality Monitoring on statements derived from the Cognitive Interview for Suspects.
    • Electrocortical indices of cognitive control in working memory : exploring the effects of proactive interference, cognitive load, and aging

      Tays, William James; Department of Psychology (Brock University, 2012-04-04)
      Cognitive control involves the ability to flexibly adjust cognitive processing in order to resist interference and promote goal-directed behaviour. Although frontal cortex is considered to be broadly involved in cognitive control, the mechanisms by which frontal brain areas implement control functions are unclear. Furthermore, aging is associated with reductions in the ability to implement control functions and questions remain as to whether unique cortical responses serve a compensatory role in maintaining maximal performance in later years. Described here are three studies in which electrophysiological data were recorded while participants performed modified versions of the standard Sternberg task. The goal was to determine how top-down control is implemented in younger adults and altered in aging. In study I, the effects of frequent stimulus repetition on the interference-related N450 were investigated in a Sternberg task with a small stimulus set (requiring extensive stimulus resampling) and a task with a large stimulus set (requiring no stimulus resampling).The data indicated that constant stimulus res amp ling required by employing small stimulus sets can undercut the effect of proactive interference on the N450. In study 2, younger and older adults were tested in a standard version of the Sternberg task to determine whether the unique frontal positivity, previously shown to predict memory impairment in older adults during a proactive interference task, would be associated with the improved performance when memory recognition could be aided by unambiguous stimulus familiarity. Here, results indicated that the frontal positivity was associated with poorer memory performance, replicating the effect observed in a more cognitively demanding task, and showing that stimulus familiarity does not mediate compensatory cortical activations in older adults. Although the frontal positivity could be interpreted to reflect maladaptive cortical activation, it may also reflect attempts at compensation that fail to fully ameliorate agerelated decline. Furthermore, the frontal positivity may be the result of older adults' reliance on late occurring, controlled processing in contrast to younger adults' ability to identify stimuli at very early stages of processing. In the final study, working memory load was manipulated in the proactive interference Sternberg task in order to investigate whether the N450 reflects simple interference detection, with little need for cognitive resources, or an active conflict resolution mechanism that requires executive resources to implement. Independent component analysis was used to isolate the effect of interference revealing that the canonical N450 was based on two dissociable cognitive control mechanisms: a left frontal negativity that reflects active interference resolution, , but requires executive resources to implement, and a right frontal negativity that reflects global response inhibition that can be relied on when executive resources are minimal but at the cost of a slowed response. Collectively, these studies advance understanding of the factors that influence younger and older adults' ability to satisfy goal-directed behavioural requirements in the face of interference and the effects of age-related cognitive decline.
    • An Electrophysiological Investigation into the Role of Cognitive Control in the Attentional Blink

      MacLean, Mary H.; Department of Psychology (Brock University, 2013-08-22)
      Accuracy at reporting a second-target (T2) is reduced if it is presented within approximately 500 ms of the first target (T1) – an attentional blink (AB). Early models explained the AB in terms of attentional limitations creating a processing bottleneck such that T2 processing would be impaired while T1 processing was ongoing. Theoretical models of the AB have more recently been expanded to include the role of cognitive control. In this dissertation I propose that cognitive control, defined as the optimization of information processing in order to achieve goals, is maladapted to the dual-task conditions of the AB task in that cognitive control optimizes the T1 goal, due to its temporal proximity, at the cost of T2. I start with the concept that the role of cognitive control is to serve goals, and that how goals are conceived of and the degree of motivation associated with those goals will determine whether cognitive control will create the condition that cause the AB. This leads to the hypothesis that electrophysiological measures of cognitive control and the degree of attentional investment resulting from cognitive control modulate the AB and explain individual differences in the AB. In a series of four studies feedback-related N2 amplitude, (reflecting individual differences in the strength of cognitive control), and event-related and resting alpha frequency oscillatory activity (reflecting degree of attentional investment), are used to explain both intra- and inter-individual variability in performance on the AB task. Results supported the hypothesis that stronger cognitive control and greater attentional investment are associated with larger AB magnitudes. Attentional investment, as measured by alpha frequency oscillations, and cognitive control, as measured by the feedback-related N2, did not relate to each other as hypothesized. It is proposed that instead of a measure of attentional investment alone, alpha frequency oscillatory activity actually reflects control over information processing over time, in other words the timing of attention. With this conceptualization, various aspects of cognitive control, either related to the management of goals (feedback-related N2) or the management of attention over time to meet goals, explain variability in the AB.
    • Electrophysiological investigations of the timing of face processing

      Zheng, Xin; Department of Psychology (Brock University, 2013-05-07)
      As important social stimuli, faces playa critical role in our lives. Much of our interaction with other people depends on our ability to recognize faces accurately. It has been proposed that face processing consists of different stages and interacts with other systems (Bruce & Young, 1986). At a perceptual level, the initial two stages, namely structural encoding and face recognition, are particularly relevant and are the focus of this dissertation. Event-related potentials (ERPs) are averaged EEG signals time-locked to a particular event (such as the presentation of a face). With their excellent temporal resolution, ERPs can provide important timing information about neural processes. Previous research has identified several ERP components that are especially related to face processing, including the N 170, the P2 and the N250. Their nature with respect to the stages of face processing is still unclear, and is examined in Studies 1 and 2. In Study 1, participants made gender decisions on a large set of female faces interspersed with a few male faces. The ERP responses to facial characteristics of the female faces indicated that the N 170 amplitude from each side of the head was affected by information from eye region and by facial layout: the right N 170 was affected by eye color and by face width, while the left N 170 was affected by eye size and by the relation between the sizes of the top and bottom parts of a face. In contrast, the P100 and the N250 components were largely unaffected by facial characteristics. These results thus provided direct evidence for the link between the N 170 and structural encoding of faces. In Study 2, focusing on the face recognition stage, we manipulated face identity strength by morphing individual faces to an "average" face. Participants performed a face identification task. The effect of face identity strength was found on the late P2 and the N250 components: as identity strength decreased from an individual face to the "average" face, the late P2 increased and the N250 decreased. In contrast, the P100, the N170 and the early P2 components were not affected by face identity strength. These results suggest that face recognition occurs after 200 ms, but not earlier. Finally, because faces are often associated with social information, we investigated in Study 3 how group membership might affect ERP responses to faces. After participants learned in- and out-group memberships of the face stimuli based on arbitrarily assigned nationality and university affiliation, we found that the N170 latency differentiated in-group and out-group faces, taking longer to process the latter. In comparison, without group memberships, there was no difference in N170 latency among the faces. This dissertation provides evidence that at a neural level, structural encoding of faces, indexed by the N170, occurs within 200 ms. Face recognition, indexed by the late P2 and the N250, occurs shortly afterwards between 200 and 300 ms. Social cognitive factors can also influence face processing. The effect is already evident as early as 130-200 ms at the structural encoding stage.
    • 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.

      Good, Marie; Department of Psychology (Brock University, 2012-07-30)
      The goal of the four studies that comprised this dissertation was to examine how spirituality/religiosity (SIR), as both an institutional and personal phenomenon, developed over time, and how its institutional (i.e., religious activity involvement) and personal (i.e., sense of connection with the sacred) components were uniquely linked with psychosocial adjustment. In Study 1, the differential longitudinal correlates of religious service attendance, as compared to involvement in other clubs, were evaluated with a sample of adolescents (n=1050) who completed a survey in grades 9, 11 and 12. Religious attendance and involvement in non-religious clubs were uniquely associated with positive adjustment in terms of lower substance use and better academic marks, particularly when involvement was sustained over time. In Study 2, the direction of effects was tested for the association between religious versus non-religious activities and both substance use and academic marks. Participants (n= 3993) were surveyed in grades 9 through 12. Higher religious attendance (but not non-religious club involvement) in one grade predicted lower levels of substance use in the next grade. Higher levels of nonreligious club involvement (but not religious service attendance) in one grade predicted higher academic achievement in the next grade, and higher academic achievement in one grade predicted more frequent non-religious club involvement in the next grade. The results suggest that different assets may be fostered in religious as compared to nonreligious activities, and, specifically, religious activity involvement may be important for the avoidance of substance use. The goal of Study 3 was to assess the unique associations between the institutional versus personal dimensions of SIR and a wide range of domains of psychosocial adjustment (namely, intrapersonal well-being, substance use, risk attitudes, parental relationship quality, academic orientation, and club involvement), and to examine the direction of effects in these associations. Participants (n=756) completed a survey in grades 11 and 12. Personal and institutional dimensions of SIR were differentially associated with adjustment, but it may only be in the domain of risk-taking (Le., risk attitudes, substance use) that SIR may predict positive adjustment over time. Finally, in Study 4, the goal was to examine how institutional and personal aspects of SIR developed within individual adolescents. Configurations of mUltiple dimensions of spirituality/religiosity were identified across 2 time points with an empirical classification procedure (cluster analysis), and sample- and individual-level development in these configurations were assessed. A five cluster-solution was optimal at both grades. Clusters were identified as aspirituallirreligious, disconnected wonderers, high institutional and personal, primarily personal, and meditators. With the exception of the high institutional and personal cluster, the cluster structures were stable over time. There also was significant intraindividual stability in all clusters over time; however, a significant proportion of individuals classified as high institutional and personal in Grade 11 moved into the primarily personal cluster in Grade 12. This program of research represented an important step towards addressing some of the limitations within the body of literature; namely, the uniqueness of religious activity involvement as a structured club, the differential link between institutional versus personal SIR and psychosocial adjustment, the direction of effects in the associations between institutional versus personal SIR and adjustment, and the way in which different dimensions of SIR may be configured and develop within individual adolescents over time.
    • Exploring the impact of outgroup membership discoveries on individual outcomes and intergroup relations

      MacInnis, Cara; Department of Psychology (Brock University, 2013-07-19)
      Group memberships represent important components of identity, with people holding membership in various groups and categories. The groups that one belongs to are known as ingroups, and the groups that one does not belong to are known as outgroups. Movement between groups can occur, such that an individual becomes a member of a former outgroup. In some cases, this movement between groups can represent a sudden discovery for the self and/or others, especially when one becomes a member of an ambiguous, concealable, or otherwise not readily visible group. The effects of this type of movement, however, are poorly documented. The purpose of this dissertation is to investigate these outgroup membership discoveries, examining the individual intrapsychic, interpersonal, and potential intergroup effects of both self- and other-outgroup membership discoveries. Specifically, discoveries of homosexuality were examined in three studies. In Study 1, hypothetical reactions to self- and other-homosexuality discovery were assessed; in Study 2, the effects of discovering self-homosexuality (vs. self-heterosexuality) were experimentally examined; and in Study 3, the effects of discovering another’s homosexuality earlier relative to later in a developing friendship were experimentally examined. Study 1 revealed that, upon a discovery of self-homosexuality, participants expected negative emotions and a more negative change in feelings toward the self. Upon a discovery of a friend’s homosexuality, participants expected a more negative change in feelings toward the friend, but more a positive change in feelings toward homosexuals. For both hypothetical self- and friend- homosexuality discoveries, more negative expected emotions predicted more negative expected change in feelings toward the target individual (the self or friend), which in turn predicted more negative expected change in feelings toward homosexuals as a group. Further, for self-homosexuality discovery, the association between negative expected emotions and negative expected change in feelings toward the self was stronger among those higher in authoritarianism. Study 2 revealed that, upon discovering one’s own homosexuality (vs. heterosexuality), heterosexual participants experienced more negative emotions, more fear of discrimination, and more negative self-evaluations. The effect of the homosexuality discovery manipulation on negative self-evaluations was mediated by fear of discrimination. Further, those higher in authoritarianism or pre-test prejudice toward homosexuals demonstrated more negative emotions following the manipulation. Study 3 revealed that upon discovering an interaction partner’s homosexuality earlier (vs. later) participants reported a more positive contact experience, a closer bond with the partner, and more positive attitudes toward the partner. Earlier (vs. later) discovery predicted more positive contact experience, which in turn predicted a closer bond with the partner. Closer bond with the partner subsequently predicted more positive evaluations of the partner. Interestingly, the association between bond with partner and more positive attitudes toward the partner was stronger among those higher in authoritarianism or pre-test prejudice toward homosexuals. Overall, results suggest that self-homosexuality discovery results in negative outcomes, whereas discovering another’s homosexuality can result in positive outcomes, especially when homosexuality is discovered earlier (vs. later). Implications of these findings for both actual outgroup membership discoveries and social psychological research are discussed.
    • 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.

      Geniole, Shawn; Department of Psychology
      As do many species, humans visually assess the ability and propensity of others to cause trouble or harm (threat potential), although the mechanisms that guide this ability are unknown. One potential mechanism that may underlie advertisements and assessments of threat is the facial width-to-height ratio (face ratio). The overarching goal of this thesis was to test both the ecological validity of the face ratio (i.e., the extent to which it maps onto an individual’s actual threat potential), and its utility in influencing observers’ first impressions of traits related to threat potential. In Chapter 2, I found that men (n = 146) but not women (n = 76) with larger face ratios were more likely to cheat in a lottery for a cash prize than were men with smaller face ratios. In Chapter 3, to better identify the precise social function of the metric, I examined its differential association with two types of threat-related judgements, untrustworthiness and aggressiveness. The face ratio (n of faces = 141) was more strongly linked to observers’ (n = 129) judgements of aggression than to their judgements of trust, although it is possible that this metric advertises threat potential more generally, of which aggression is a best indicator. In Chapter 4 (which extended some preliminary, additional findings from Chapter 3), I found that observers’ (n = 56) judgements of aggression were strongly correlated with the face ratio (n of faces = 25) even when men were bearded, suggesting that this metric could have been operational in our ancestral past when interactions likely involved bearded men. In Chapter 5, I combined effect sizes from experiments conducted from several independent labs and identified significant (albeit weak) associations between the face ratio and actual threat behaviour, and significant (and stronger) associations between the face ratio and judgements of threat potential. Together, this body of work provides initial evidence that the face ratio, and sensitivity to it, may be part of an evolved system designed for advertising and assessing threat in humans, akin to threat assessment systems identified in other species.
    • Genetic and Electrophysiological Correlates of Self-Regulation in Adolescence

      Lackner, Christine; Department of Psychology
      Self-regulation is considered a powerful predictor of behavioral and mental health outcomes during adolescence and emerging adulthood. In this dissertation I address some electrophysiological and genetic correlates of this important skill set in a series of four studies. Across all studies event-related potentials (ERPs) were recorded as participants responded to tones presented in attended and unattended channels in an auditory selective attention task. In Study 1, examining these ERPs in relation to parental reports on the Behavior Rating Inventory of Executive Function (BRIEF) revealed that an early frontal positivity (EFP) elicited by to-be-ignored/unattended tones was larger in those with poorer self-regulation. As is traditionally found, N1 amplitudes were more negative for the to-be-attended rather than unattended tones. Additionally, N1 latencies to unattended tones correlated with parent-ratings on the BRIEF, where shorter latencies predicted better self-regulation. In Study 2 I tested a model of the associations between selfregulation scores and allelic variations in monoamine neurotransmitter genes, and their concurrent links to ERP markers of attentional control. Allelic variations in dopaminerelated genes predicted both my ERP markers and self-regulatory variables, and played a moderating role in the association between the two. In Study 3 I examined whether training in Integra Mindfulness Martial Arts, an intervention program which trains elements of self-regulation, would lead to improvement in ERP markers of attentional control and parent-report BRIEF scores in a group of adolescents with self-regulatory difficulties. I found that those in the treatment group amplified their processing of attended relative to unattended stimuli over time, and reduced their levels of problematic behaviour whereas those in the waitlist control group showed little to no change on both of these metrics. In Study 4 I examined potential associations between self-regulation and attentional control in a group of emerging adults. Both event-related spectral perturbations (ERSPs) and intertrial coherence (ITC) in the alpha and theta range predicted individual differences in self-regulation. Across the four studies I was able to conclude that real-world self-regulation is indeed associated with the neural markers of attentional control. Targeted interventions focusing on attentional control may improve self-regulation in those experiencing difficulties in this regard.
    • 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.
    • Indices and Implications of Emotional Underarousal for Persons with a History of Head Trauma

      Baker, Julie; Department of Psychology (Brock University, 2014-12-12)
      We examined the role of altered emotional functioning across the spectrum of injury severity (mild head injury [MHI], moderate/severe traumatic brain injury [TBI]), its implications for social behaviours, and the effect of modifying arousal and its relation to cognitive performance. In the first study (N = 230), students with self-reported MHI endorsed engaging in socially unacceptable and erratic behaviours significantly more often than did those with no MHI. We did not find significant differences between the groups in the measure of emotional intelligence (EI); however, for students who reported a MHI, scores on the EI measure significantly predicted reports of socially unacceptable behaviours such that lower scores predicted poorer social functioning, accounting for approximately 20% of the variance. Also, the experience of postconcussive symptoms was found to be significantly greater for students with MHI relative to their peers. In the second study (N = 85), we further examined emotional underarousal in terms of physiological (i.e., electrodermal activation [EDA]) and self-reported responsivity to emotionally-evocative picture stimuli. Although the valence ratings of the stimuli did not differ between students with and without MHI as we had expected, we found evidence of reduced and/or indiscriminate emotional responding to the stimuli for those with MHI which mimics that observed in other studies for persons with moderate/severe TBI. We also found that emotional underarousal followed a gradient of injury severity despite reporting a pattern of experiencing more life stressors. In the third study (N = 81), we replicated our findings of emotional underarousal for those with head trauma and also uniquely explored neuroendocrine aspects (salivary cortisol; cortisol awakening response [CAR]) and autonomic indices (EDA) of emotional dysregulation in terms of stress responsivity across the spectrum of injury severity (MHI [n = 32], moderate/severe TBI [n = 9], and age and education matched controls [n = 40]). Although the manipulation was effective in modifying arousal state in terms of autonomic and self-reported indices, we did not support our hypothesis that increased arousal would be related to improved performance on cognitive measures for those with prior injury. To our knowledge, this is the only study to examine the CAR with this population. Repeated measure analysis revealed that, upon awakening, students with no reported head trauma illustrated the typical CAR increase 45 minutes after waking, whereas, students who had a history of either mild head trauma or moderate/severe TBI demonstrated a blunted CAR. Thus, across the three studies we have provided evidence of emotional underarousal, its potential implications for social interactions, and also have identified potentially useful indices of dysregulated stress responsivity regardless of injury severity.