• Sleep and information processing in individuals who have sustained a traumatic brain injury

      Milner, Catherine; Department of Psychology (Brock University, 2011-05-17)
      Individuals who have sustained a traumatic brain injury (TBI) often complain of t roubl e sleeping and daytime fatigue but little is known about the neurophysiological underpinnings of the s e sleep difficulties. The fragile sleep of thos e with a TBI was predicted to be characterized by impairments in gating, hyperarousal and a breakdown in sleep homeostatic mechanisms. To test these hypotheses, 20 individuals with a TBI (18- 64 years old, 10 men) and 20 age-matched controls (18-61 years old, 9 men) took part in a comprehensive investigation of their sleep. While TBI participants were not recruited based on sleep complaint, the fmal sample was comprised of individuals with a variety of sleep complaints, across a range of injury severities. Rigorous screening procedures were used to reduce potential confounds (e.g., medication). Sleep and waking data were recorded with a 20-channel montage on three consecutive nights. Results showed dysregulation in sleep/wake mechanisms. The sleep of individuals with a TBI was less efficient than that of controls, as measured by sleep architecture variables. There was a clear breakdown in both spontaneous and evoked K-complexes in those with a TBI. Greater injury severities were associated with reductions in spindle density, though sleep spindles in slow wave sleep were longer for individuals with TBI than controls. Quantitative EEG revealed an impairment in sleep homeostatic mechanisms during sleep in the TBI group. As well, results showed the presence of hyper arousal based on quantitative EEG during sleep. In wakefulness, quantitative EEG showed a clear dissociation in arousal level between TBls with complaints of insomnia and TBls with daytime fatigue. In addition, ERPs indicated that the experience of hyper arousal in persons with a TBI was supported by neural evidence, particularly in wakefulness and Stage 2 sleep, and especially for those with insomnia symptoms. ERPs during sleep suggested that individuals with a TBI experienced impairments in information processing and sensory gating. Whereas neuropsychological testing and subjective data confirmed predicted deficits in the waking function of those with a TBI, particularly for those with more severe injuries, there were few group differences on laboratory computer-based tasks. Finally, the use of correlation analyses confirmed distinct sleep-wake relationships for each group. In sum, the mechanisms contributing to sleep disruption in TBI are particular to this condition, and unique neurobiological mechanisms predict the experience of insomnia versus daytime fatigue following a TBI. An understanding of how sleep becomes disrupted after a TBI is important to directing future research and neurorehabilitation.
    • Social Anxiety and Psychosocial Functioning: Investigating Relations Across Emerging Adulthood

      Brook, Christina; Department of Psychology
      The social, emotional and academic tasks associated with emerging adulthood are particularly challenging for those with social anxiety, a behavior defined as fear of negative evaluation, distress with social interactions, and/or avoidance of new or all social situations. The goal of this dissertation was to research the longitudinal effects of social anxiety on psychosocial functioning in university students, looking at various behaviors key to this developmental stage of life. In my first study, I examined the relation between social anxiety, social ties, and academic achievement in an autoregressive cross-lagged analysis across three years of university. There were two major findings: the symptoms of social anxiety directly linked to academic achievement, and social ties appeared to play a pivot role through their reciprocal negative and positive relation with social anxiety and academic achievement, respectively. Study two examined social anxiety with respect to alcohol use over three years of university through latent class growth analysis. Five classes were identified, two with social anxiety that differed in levels of alcohol use, and three with low social anxiety and varying levels of alcohol use. The heterogeneity in social anxiety was related to psychosocial functioning. While both social anxiety groups reported similar social anxiety symptomology, only the group linked to higher alcohol use exhibited a greater vulnerability to other at-risk behaviors in year one (e.g., self injury). The third study followed the previously identified five groups through latent growth analysis for a total of seven years, to determine whether there was stability or change in psychosocial functioning over the long term. The results indicated that there was stability within and among groups across time in psychosocial functioning. Notably, the differences detected between the two social anxiety groups in year one continued over the long term, indicating that the at-risk behaviors associated with the social anxiety group reporting higher alcohol use persisted. Overall, this program of research revealed that those with social anxiety in university struggled more than their peers in a variety of domains. From a developmental perspective, the findings of stability in behavior suggested it might be important for intervention and prevention programs to target younger populations with strategies that are continued in a cohesive manner across university, a time when students are exposed to the pressures of achieving in competing developmental tasks.
    • Social neuroendocrinology of competition

      Carré, Justin M.; Department of Psychology (Brock University, 2010-10-26)
      The relationship between testosterone concentrations and aggressive behaviour in studies of people has produced very inconsistent findings. However, one consistent fmding that has emerged is that competitive and aggressive interactions potentiate testosterone release in both human and non-human species. It has been argued that socially-induced alterations in testosterone concentrations may function to influence ongoing and/or future social behaviour. Nonetheless, few studies have empirically tested this hypothesis. The current series of experiments was designed to address the extent to which competitioninduced fluctuations in testosterone concentrations were associated with ongoing and/or subsequent social behaviour. In Study 1, men (n = 38) provided saliva samples prior to, and at the conclusion of, the Point Subtraction Aggression Paradigm (PSAP). Although baseline testosterone concentrations were not related to aggressive behaviour, there was a positive correlation between change in testosterone and aggressive behaviour such that men who were most aggressive on the PSAP demonstrated the largest increase in testosterone concentrations. Furthermore, a rise in testosterone during the PSAP predicted willingness to choose a subsequent competitive task. In Study 2, men and women provided saliva samples prior to and after competing against a same-sex opponent on the Number Tracing Task (NTT). The outcome of the competition was rigged such that half of the individuals won most of the races, while the other half lost most of the races, thus experimentally creating a winner and loser in the laboratory. Following the competitive interaction, men and women played the PSAP with their same-sex partner. Results indicated that men selected the aggressive response (but not reward or protection responses), more frequently than women. For men assigned to the loss condition, an increase in testosterone concentrations in response to the NTT predicted subsequent aggressive behaviour. For men assigned to the win condition, an increase in testosterone concentrations in response to the NTT predicted subsequent aggressive behaviour, but only among those men who scored high on trait dominance. Change in testosterone and trait dominance did not predict aggressive behaviour in women. In Study 3, men provided saliva samples prior to, during, and at the end of the PSAP. They were randomly assigned to one of four experimental conditions that differed in the extent to which they were provoked and whether they received reward for behaving aggressively (i.e., stealing points). Results indicated that baseline testosterone concentrations did not correlate with aggression in any of the experimental conditions. Consistent with Study 1, there was a positive correlation between change in testosterone and aggressive behaviour among men who were provoked, but did not receive reward for aggression (i.e., reactive condition). Men who were provoked but did not receive reward for aggression enjoyed the task the most and were more likely to choose the competitive versus non-competitive task relative to men assigned to the other experimental conditions. Also, individual differences in aggressive behaviour among these men were positively correlated with the extent to which they enjoyed the task. Together, these studies indicate that testosterone dynamics within the context of competition influence subsequent competitive and aggressive behaviours in humans and that testosterone may be a marker of the intrinsically rewarding nature of costly aggressive behaviour.
    • Testing a Hypothesis of Non-REM Sleep Reinforcement and REM Sleep Refinement for the Benefits of Post-Learning Sleep on Memory Retrieval

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

      Dzyundzyak, Angela; Department of Psychology (Brock University, 2014-07-18)
      The Feedback-Related Negativity (FRN) is thought to reflect the dopaminergic prediction error signal from the subcortical areas to the ACC (i.e., a bottom-up signal). Two studies were conducted in order to test a new model of FRN generation, which includes direct modulating influences of medial PFC (i.e., top-down signals) on the ACC at the time of the FRN. Study 1 examined the effects of one’s sense of control (top-down) and of informative cues (bottom-up) on the FRN measures. In Study 2, sense of control and instruction-based (top-down) and probability-based expectations (bottom-up) were manipulated to test the proposed model. The results suggest that any influences of medial PFC on the activity of the ACC that occur in the context of incentive tasks are not direct. The FRN was shown to be sensitive to salient stimulus characteristics. The results of this dissertation partially support the reinforcement learning theory, in that the FRN is a marker for prediction error signal from subcortical areas. However, the pattern of results outlined here suggests that prediction errors are based on salient stimulus characteristics and are not reward specific. A second goal of this dissertation was to examine whether ACC activity, measured through the FRN, is altered in individuals at-risk for problem-gambling behaviour (PG). Individuals in this group were more sensitive to the valence of the outcome in a gambling task compared to not at-risk individuals, suggesting that gambling contexts increase the sensitivity of the reward system to valence of the outcome in individuals at risk for PG. Furthermore, at-risk participants showed an increased sensitivity to reward characteristics and a decreased response to loss outcomes. This contrasts with those not at risk whose FRNs were sensitive to losses. As the results did not replicate previous research showing attenuated FRNs in pathological gamblers, it is likely that the size and time of the FRN does not change gradually with increasing risk of maladaptive behaviour. Instead, changes in ACC activity reflected by the FRN in general can be observed only after behaviour becomes clinically maladaptive or through comparison between different types of gain/loss outcomes.
    • Understanding the Complex Mental Health Challenges of Children and Adolescents Seeking Community-based Care

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

      Pozzebon, Julie A.; Department of Psychology (Brock University, 2013-05-07)
      This dissertation addressed several questions relevant to vocational interests and personality characteristics, examining (a) the roles of personality, vocational interests, and sexual fantasies in defining a general factor of Masculinity/Femininity (M/F) (Study 1), (b) the validity of a new measure of vocational interests (Study 2), and (c) the individual difference characteristics that discriminate between students in various academic majors, and that predict academic outcomes (Study 3). In Study 1, vocational interests, personality, and sexual fantasies were examined to find whether these variables would yield a general Masculinity/Femininity (M/F) factor, and whether that factor would still emerge when controlling for participant sex. The results of Study 1 revealed that a general factor of M/F did emerge. When sex was removed, the loadings of vocational interests decreased from high to very low, suggesting that the link of vocational interests with other indicators of M/F is mainly due to sex differences in these variables. The purpose of Study 2 was to validate the Oregon Vocational Interest Scales (ORVIS), a new public domain vocational interests questionnaire designed to measure eight vocational interest scales. ORVIS scores obtained in a college and community sample were compared with those of two personality measures and two cognitive ability tests. Results from this study showed that the ORVIS scales were reliable and showed good construct validity. The purpose of Study 3, using the ORVIS along with the HEXACO-PI and tests of cognitive ability, was to examine the individual difference characteristics of students in different academic majors, and to use the congruence between a student's academic major and vocational interests as a predictor of academic outcomes, such as GPA, academic major change, and satisfaction with major. The results of Study 3 revealed that students in different academic majors show theoretically meaningful differences in personality, abilities, and interests. Conscientiousness and math ability were found to be the best predictors of academic outcomes. However, congruence between major and interests did not add significant predictive validity to any of these outcomes beyond personality and ability. Together, these three studies show the role of vocational interests in defming MlF and in predicting various academic outcomes.
    • When and why is religious attendance associated with anti-gay bias? A justification-suppression model approach

      Hoffarth, Mark; Department of Psychology
      Even in relatively tolerant countries, anti-gay bias remains socially divisive, despite being widely viewed as violating social norms of tolerance. From a Justification-Suppression Model (JSM) framework, social norms may generally suppress anti-gay bias in tolerant countries, yet bias may be “released” by religious justifications among those who resist gay rights progress. I hypothesized that more frequent religious attendance would be associated with greater anti-gay bias, that this relation would be stronger in countries where anti-gay bias more strongly violates social norms of tolerance, and that the relation between religious attendance and anti-gay bias would be partially accounted for by religious justifications. In Part 1, I examined the relation between religious attendance and anti-gay bias in the US. In Part 2, I examined the relation between religious attendance and anti-gay bias across different countries. Finally, in Part 3, I examined religious justifications for anti-gay bias. Across large, nationally representative US samples and international samples (representing a total of 97 different countries), over 215,000 participants, and various indicators of anti-gay bias (e.g., dislike, moral condemnation, opposing gay rights), more frequent religious attendance was uniquely associated with greater anti-gay bias, over and above religious fundamentalism, political ideology, religious denomination, and other theoretically relevant covariates. Moreover, in 4 of 6 multilevel models, religious attendance was associated with anti-gay bias in countries with greater gay rights recognition, but was unrelated to anti-gay bias in countries with lower gay rights recognition. Google searches for a religious justification (“love the sinner hate the sin”) coincided temporally with gay-rights relevant searches. In U.S. and Canadian samples, much of the association between religious attendance and anti-gay bias was explained by “sinner-sin” religious justification, with religious attendance not associated with anti-gay bias when respondents reported relatively low familiarity with this justification. These findings suggest that social divisions on homosexuality in relatively tolerant social contexts may be in large part due to religious justifications for anti-gay bias (consistent with the JSM). Potential interventions building on these findings may include encouraging religious leaders to promote norms of tolerance and acceptance, increasing intergroup contact between frequent religious attenders and gays, and perspective-taking exercises.
    • Who Bullies and When? Concurrent, Longitudinal, and Experimental Associations between Personality and Social Environments for Adolescent Bullying Perpetration

      Farrell, Ann; Department of Psychology
      Increasing evidence suggests that bullying may be used by adolescents as a strategic, adaptive tool against weaker peers to obtain valued resources like social status and romantic partners. However, bullying perpetration may only be adaptive within particular environmental contexts that provide opportunities to obtain these resources at minimal costs. These environmental opportunities may be relevant for adolescents who possess particular personality traits and are motivated to exploit these contexts and power imbalances. Using an adaptive social ecological framework, the primary goal of my dissertation was to examine concurrent, longitudinal, and experimental associations between exploitative personality traits and broader social ecologies to facilitate adolescent bullying perpetration. In Study 1, I examined whether risky social environments filtered through antisocial personality traits to facilitate direct and indirect forms of bullying perpetration in a cross-sectional sample of 396 adolescents. In Study 2, I extended Study 1 by investigating the longitudinal associations among bullying, empathic and exploitative personality traits, and social environmental variables, in a sample of 560 adolescents across the first three years of high school. Given that Studies 1 and 2 were correlational, in Study 3, I explored whether bullying perpetration could be experimentally simulated in a laboratory setting through point allocations in the Dictator and Ultimatum economic games by manipulating power imbalances in a sample of 167 first-year undergraduate students. Results from all three studies largely supported the prediction that broader social ecologies filter through exploitative personality styles to associate with bullying perpetration. Exploitative adolescents are primarily likely to take advantage of particular contexts including power advantages, higher social status, and poorer school and neighborhood climates. The results of my dissertation demonstrate the complex reality of the social ecology of bullying, and the need for anti-bullying initiatives to target multiple contexts including individual differences.
    • Why are people liberal? : a motivated social cognition perspective

      Choma, Becky L.; Department of Psychology (Brock University, 2008-05-28)
      The present dissertation examined why people adopt or endorse certain political ideologies (i.e., liberal or conservative). According to a motivated social cognition perspective (Jost, Glaser, Kruglanski, & Sulloway, 2003a; Kruglansl<i, 1996), individuals adopt political ideologies to fulfill dispositional and situationally induced needs or motivations. Previous research has found that political conservatism is related to a number of psychological needs (e.g., Jost, Glaser et aI., 2003a). However, there is minimal research examining why individuals adopt political liberalism. By focussing on the political right and not considering the political left, there might be other motivational underpinnings of political orientation that have been overlooked. In four studies, the present dissertation ail)1ed to fill this gap by investigating what chronic and situationally induced needs underlie political orientation, with a focus on political liberalism. Based on psychological the9ries of ideology, research examining political conservatism, and experimental research examining differences between liberals and conservatives, it was proposed that four social-cognitive needs (Need for Inclusiveness, Need for Understanding, Need for Change, and Avoidance of Decisional Commitment) would be associated with liberalism. Moreover, research suggests that the relations between the needs and liberalism might be moderated by political sophistication (e.g., Converse, 1964). University students (Study 1; n == 201) and community adults (Study 2; n == 197) completed questionnaires assessing political liberalism, political sophistication, and individual differences 're~ective of the four proposed needs. As predicted, correlation and hierarchical regression analyses in both Studies 1 and 2 indicated that political liberalism was related to Need for Inclusiveness, Need for Understanding, and Need for Change. 11 Avoidance of Decisional Commitment uniquely predicted political liberalism in Study 2; however, contrary to predictions, it was unrelated to political liberalism in Study 1. Furthermore, some of these relations were moderated by political sophistication, such that among individuals with a greater knowledge of politics, the relation between certain needs and liberalism was positive. To explore the role of situationally induced needs on political liberalism, each of the four proposed needs were manipulated in Study 3. Participants (n == 120) completed one of five scrambled-sentence tasks (one for each need condition and control condition), measures of explicit and implicit political liberalism, political sophistication, and state and trait measures indicative of the four proposed needs. The ~anipulation did not successfully prime participants with the needs. Therefore, a replication of the analyses from Studies 1 and 2 was conducted on the dispositional needs. Results showed that Need for Inclusiveness, Need for Understanding, and Need for Change were linked with greater explicit and implicit political liberalism. Study 4 examined the effect of manipulated Need for Inclusiveness on participants' endorsement ofpolitical liberalism, independent of conservatism. Participants (n == 43) were randomly assigned to a Need for Inclusiveness or control condition, and completed separate measures of political liberalism and conservatism, and political sophistication. Participants in the Need for Inclusiveness condition reported greater liberalism than those in a control condition; this effect was not moderated by political sophistication. Generally, the findings from this dissertation suggest that there might be other needs underlying political ideology, especially political liberalism. Thus, consistent with others' (Jost, Glaser et aI., 2003a), individuals might adopt political liberalism as a way of gratifying certain psychological needs. Implications and future research are discussed.
    • Youth Involvement in Organizational Decision Making: The Connection to Youth Initiative and Organizational Functioning

      Ramey, Heather; Department of Psychology (Brock University, 2012-07-31)
      Studying positive adolescent development requires an examination of the mutually beneficial associations between youth and their environment. These youthcontext relations include both the contributions that youth make to others and society and the youth-context interactions that might predict positive youth outcomes. Community and youth-serving organizations, where youth may be involved in decision-making roles such as service delivery, advocacy, or on boards of directors, can provide one important context for youth contributions and for positive adolescent development. Research on the outcomes of youth involvement in organizational decision-making, however, is limited, and largely consists of exploratory qualitative studies. This dissertation is formatted as an integrated article dissertation. It begins with a review of the literature on contexts of structured youth activities and positive youth development. This review is intended to describe theory on development-context relations, in which development is considered an interactive process that occurs between individuals and their contexts, as it pertains the positive development of youth who are involved in various structured activities (e.g., volunteering). This description follows with a review of current research, and conclusions and rationale for the current studies. Following this theoretical and research background, the dissertation includes reports of two studies that were designed to address gaps in the research on youth involvement in organizational decision-making. The first was a qualitative research synthesis to elucidate and summarize the extant qualitative research on the outcomes of youth involvement in organizational decision making on adults and organizations. Results of this study suggested a number of outcomes for service provision, staff, and broader organizational functioning, including both benefits to organizations as well as some costs. The second study was a quantitative analysis of the associations among youth involvement, organizations' learning culture, and youth initiative, and relied on survey data gathered from adults and youth in community-based organizations with youth involvement. As expected, greater youth involvement in organizational decision making was associated with higher learning culture within the organization. Two dimensions of youth involvement, greater program engagement and relationships with adults, were related to greater youth initiative. A third dimension, sense of ownership, was not- .-.- associated with youth's level of initiative. Moreover, the association between relationships with adults and youth initiative was only significant in organizations with relatively low learning culture. Despite some limitations, these studies contribute to the research literature by providing some indication of the potential benefits and costs of youth involvement and by making an important contribution toward the early stages of context-level analyses of youth development. Findings have important implications for practitioners, funders, future research, and lifespan development theory.