Melbourne School of Psychological Sciences - Theses

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    The Associative Basis of Semantic Processing during Comprehension
    Shabahang, Kiavash ( 2023-08)
    The current thesis presents converging experimental and computational evidence for the centrality of retrieval operations during the comprehension of linguistic material, and develops an associative theory of semantic processing. Chapter 1 outlines the broad theoretical antecedents with a focus on the tension between symbolic and associative representations of meaning, arguing for a structural distinction between associations. Chapter 2 presents an associative network simulation of semantic memory and shows how assuming a spreading activation through a network of direct associations can match the variance in human free word association and word similarity data, traditionally explained by latent-representation semantic memory models. Instead of assuming generalization during encoding as in the latent-representation accounts, the Dynamic-Eigen-Net algorithm is presented as a way to defer generalization until retrieval through spreading activation in the network. Chapter 3 further extends the Dynamic-Eigen-Net to serial-order associations and shows how the Dynamic-Eigen-Net is better able to discriminate consistent and inconsistent novel bi-grams compared to standard spreading activation algorithms. Chapter 4 presents experiments that introduce challenges to the direct-encoding account of paradigmatic formation, where paradigmatic relations are assumed to correspond to directly encoded associations. Over a series of experiments, reliable evidence for the presence of syntagmatic associations is presented, but evidence for paradigmatic associations was inconclusive. Chapter 5 undertakes a comparison of the direct encoding account of paradigmatic relations and alternative theories. The results provide clear evidence in support of the retrieval account of paradigmatic relations, where paradigmatic relations are dynamically formed during retrieval. Chapter 6 revisits the Dynamic-Eigen-Net, presenting one way order-independent and -dependent associations can be integrated in an associative network model of the Syntagmatic-Paradigmatic framework. Chapter 7 concludes with a focus on challenges to overcome to pave the way towards an associative theory of semantic composition.
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    Associations between estradiol, brain structure and function, and extinction recall in adolescents
    Zwaan, Isabel Sterre ( 2023-08)
    Background: Adolescence is a life stage where anxiety and depressive (internalising) disorders emerge. Internalising disorders are twice as prevalent in females as males, a pattern apparent in adolescence. This sex disparity may be explained by pubertal and neurodevelopmental factors, as dramatic hormonal changes and dramatic brain changes occur during adolescence. Individual differences in pubertal hormones may interact with neurodevelopment to impact mental health. The sex steroid hormone estradiol is key in puberty, however few studies have examined associations between estradiol, neurodevelopment, and internalising symptoms, particularly in adolescents. In fact, estradiol may influence neural networks important for emotional processing and regulation, where alterations in these neural networks may underlie emotion dysregulation underlying internalising disorders. Aims: This thesis aims to investigate associations between estradiol variability (secondarily, average estradiol) and brain structure in female adolescents, as well as whether brain structure mediates longitudinal associations between estradiol variability and internalising symptoms. Further, we aim to investigate associations between estradiol variability (secondarily, average estradiol and estradiol level) and brain activation during emotion processing, as well as whether brain function mediates longitudinal associations between estradiol variability and internalising symptoms. Finally, the current thesis aims to explore associations between brain structure, fear extinction recall and trait and state anxiety symptoms, as well as moderating effects of age and sex, in a pilot study of adults and adolescents. Method: Study 1 and Study 2 of this thesis utilised the same sample of 44 female participants measured at age ~12 years (baseline) and age 13 years (follow-up). At baseline adolescents completed self-report questionnaires measuring anxiety (Spence Children’s Anxiety Scale) and depressive (Children’s Depression Inventory 2) symptoms, four saliva samples across one month to measure estradiol, and an MRI scan. In the MRI scan we collected T1-weighted images measuring brain structure for Study 1, and BOLD activation during a passive emotional face viewing task (including angry, fearful, calm faces) for Study 2. At follow-up, participants completed questionnaires measuring internalising symptoms. We utilised average estradiol and estradiol variability for both studies and estradiol on day of scan (the fourth saliva sample) for Study 2, using these to examine associations to brain structure and function during the emotional faces task and to internalising symptoms. In Study 3 we used pilot data from a sample of 18 adults and 20 adolescents who completed a fear conditioning, extinction learning, extinction recall, re-conditioning, and re-extinction fMRI task (a variant of the ‘screaming lady’ paradigm) and examined associations between skin conductance response during extinction recall and brain regions of interest in both groups combined and adolescents only, examining moderating effects of age group and sex. Additionally, we examined correlations between extinction recall, region of interest, and self-reported state and strait anxiety (State-Trait Anxiety Inventory). Results: We found that increased estradiol variability was associated with decreased right medial orbitofrontal cortex (mOFC) thickness, however there was no association between average estradiol and brain structure. Additionally, we found that estradiol on day of scan (but not average estradiol or estradiol variability) was associated with decreased precuneus and precentral gyrus and increased angular gyrus and frontal orbital cortex during processing of negatively valenced vs calm faces. We did not find associations between estradiol and internalising symptoms, or brain structure or function and internalising symptoms. In our pilot study, preliminary findings indicated that lateral OFC thickness was associated with extinction recall response in male, but not female, adolescents, while increased skin conductance response to the threat signal during extinction recall was associated with increased right mOFC thickness in adults. Further, we found a positive correlation between trait anxiety and right mOFC thickness and negative correlation between state anxiety and extinction recall response in adults and adolescents, and a positive correlation between trait anxiety and left medial OFC thickness in adolescents. Significance: To the best of our knowledge, these were the first studies examining associations between estradiol variability and brain structure and function in adolescents. We extended existing literature by demonstrating that increased estradiol variability, and not average estradiol, was associated with decreased vmPFC thickness (a region important for emotion regulation and fear extinction learning and extinction recall) in female adolescents at age 12. Further, we demonstrated that estradiol may module vmPFC activation during emotion processing, potentially facilitating emotion regulation. In our pilot study we (preliminarily) found that sex moderated the association between lateral OFC thickness and extinction recall response in adolescents, thereby extending the limited research on brain structure and extinction recall by indicating that sex differences may be present in these associations. Together, our findings support the notion that female sex steroids have organizational and activational effects on the brain, and that adolescence is a sensitive period of development.
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    Sleep disturbance as a feature of dementia with Lewy bodies
    Salthouse, Olivia Rose ( 2023-07)
    Dementia with Lewy bodies (DLB) is considered the second most common form of dementia after dementia of the Alzheimer’s type. While DLB has been considered its own diagnostic entity for approximately 30-years, several aspects of the clinical presentation remain enigmatic and require further research. Sleep is one such feature. Rapid eye movement (REM) sleep behaviour disorder (RBD) is a prominent feature of DLB and research over the past two decades has shown that it often precedes the onset of other clinical disease features by many years. The striking relationship between RBD and DLB has placed the REM stage of sleep at the forefront of sleep research in this population. Less consideration has been given to other aspects of sleep, yet clinical anecdote and case study evidence strongly suggest that sleep disruption is a pervasive clinical phenomenon, which plays itself out across all stages of sleep, affecting sleep quality, sleep structure, sleep electrophysiology and sleep behaviour. The aims of the current thesis were three-fold: 1) to comprehensively characterise the sleep profile of those in the early stages of probable DLB using actigraphy and PSG recording methods, 2) to characterise the most sensitive areas of cognition in DLB (attentional function and visual processing), and 3) to examine the relationship between sleep disruption and these sensitive areas of cognition in DLB. Participants were nine individuals with early stage DLB and nine age- and education-matched healthy older adults. Actigraphy and PSG sleep recording methods were used to objectively measure sleep quality and architecture. Participants underwent overnight in-home polysomnography (PSG) monitoring on 2 nights and completed 14 days of continuous actigraphy recording. Subjective sleep was measured using self-report questionnaires. Standardised neuropsychological measures assessed visuoperceptual and visuospatial function. Two computerised reaction time paradigms were completed by participants and provided a comprehensive measure of attentional function. This research documents significant disruptions to sleep quality and architecture in individuals with DLB. Actigraphy data revealed reduced sleep quality (reduced sleep efficiency and greater wake after sleep onset) and greater intra-individual variability in sleep quality from night-to-night. Greater variability in daytime sleep/inactivity was also documented. Overnight PSG revealed changes to sleep macrostructure and microstructure. Increased stage 1 sleep (N1), reduced stage 3 sleep (N3), and fewer microstructural features (sleep spindles and K-complexes) were documented. Sleep stage distribution throughout the night was also altered from the typical trajectory; as sleep progressed across the night, the relative distributions of sleep stages remained comparable, particularly for REM sleep. Examination of relationships between sleep and cognition revealed strong and consistent associations in those with DLB. Reduced sleep quality and increased variability in sleep quality were strongly associated with attentional impairment and in particular, attentional variability. Greater variability in daytime sleep/inactivity was also associated with more severe attentional impairment in DLB. Visual processing was largely independent of sleep. Pervasive sleep disruption is a clinical feature of DLB that emerges early in the course of disease. Disruption is represented across all aspects of sleep architecture, and impacts night time sleep and daytime functioning. These disturbances are characterised by prominent intra-individual variability and represent another fluctuating feature of this active and turbulent disease. These findings point to a loss of sleep macro- and micro-structure and suggest loss of structural definition in sleep, and more broadly a breakdown in the boundaries that typically separate the stages of sleep and the states of sleep and wakefulness. Empirical support for associations between sleep disruption and the quintessential cognitive features suggests a common underlying mechanism may underpin both sleep and cognition. This has key implications for understanding the origins of these dynamic features. Broad sleep disturbance is an early and prominent clinical symptom and offers a promising road for better understanding DLB and the neurological mechanisms which underly the enigmatic clinical symptoms of the disease.
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    A Model of Source Memory for Continuous Outcomes: Characterising Retrieval and Decision-Making
    Zhou, Jason ( 2023-09)
    Source memory is the ability to remember the origin of information stored in memory. Source memory has been of growing interest to memory researchers because influential models of episodic memory make opposing predictions about its properties. Particularly contentious is whether source memory retrieval is thresholded (i.e., fails discretely), or continuous (i.e., graded precision). Recent work has shifted away from tasks with discretely coded sources towards ones where both source presentation and responses are continuous. Distributions of source error in continuous-outcome tasks were observed to be highly leptokurtic with heavy tails, interpretable as a mixture of high-precision memory, and uniformly distributed guesses due to retrieval failure. This thesis critically evaluates this interpretation along two main lines of inquiry, the first related to the role of decision-making and the second related to intrusion errors. First, Study 1 applies a formal model of decision-making in the Smith (2016) circular diffusion model to distinguish between properties of decision-making and memory in the continuous-outcome task. Without a model of decision-making, response variability in decision-making can be erroneously attributed to memory processes. Models with decision-making variability and guessing in isolation and in combination were fit to joint distributions of response outcomes and times. Comparison of model fits revealed that guessing was necessary for good fit, suggesting that heavy tails in the distribution of response error is due to memory, rather than decision-making. Study 1 also conditioned participants’ source responding on their confidence in an old/new recognition task, addressing a potential confound by ruling out the possibility that participant guessing was only due to a lack of source memory for unrecognised items. Second, Studies 2 and 3 both concern the role of intrusion errors. Intrusions are responses driven by information retrieved about items other than the target on a trial. Although they represent a form of memory error, the error is in the binding between the items and sources, rather than the retrieval failure implied by guessing. However, when items are randomly distributed on the response domain, intrusions from non-target items mimic errors due to guessing. Across two experiments, Study 2 found evidence of intrusion responses, and showed that when these are explicitly modelled the estimated proportion of guesses decreased. Further elaboration of the intrusion model indicated that items studied in nearby positions in space and time were more likely to intrude. Surprisingly, neither the semantic nor perceptual features of cues had a similar effect. Study 3 manipulated these item features and found that intrusions were more likely when orthographic similarity was high across the list, but not semantics. Overall, these studies demonstrate that some, though not all, apparent guesses can be explained by intrusions, which are related to the similarity of items and contexts. Ultimately, these studies suggest that guessing occurs even when alternative explanations for heavy-tailed distributions of error are considered. Using a model of decision-making and intrusion processes, this thesis connects source memory research to parallel theories in the visual working memory literature. In doing so, it provides the most detailed characterisation of source memory with continuous outcomes to date.
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    Predicting post-concussive symptoms and behaviour outcomes in preschool mild TBI: A prospective study
    Yumul, Joy Noelle Tolentino ( 2023-07)
    Background: Mild traumatic brain injury (mTBI) makes up approximately 90% of all childhood TBIs. Post-concussive symptoms (PCS) and behaviour problems have been documented after mTBI, but their presentation and progression remain poorly understood in preschool children. Of note, the available literature on preschool mTBI is primarily based on parent report, and little is known regarding variables that may impact parents’ report of problems in their child months after the injury. Given the vulnerability of preschool children to mTBI, and the gaps in the current knowledge, the overarching aims of this thesis were to explore PCS and behaviour problems that parents report in preschool children, and to investigate variables, including observed parent-child interaction, which may be associated with parent report. Method: To address these aims, the thesis is composed of three parts. Part I was a cross-sectional study that investigated the proportion of children aged 2-12 years with PCS at three months post-injury and examined potential predictors of parent report. Part II was a systematic review of 11 studies that provided data on post-concussive signs and symptoms in preschool children, where information on PCS and signs of injury (e.g., loss of consciousness) were consolidated and the quality of the evidence was appraised. Part III was a prospective longitudinal study, which documented PCS and behaviour outcomes in children aged 2-5 years up to three months post-mTBI. It also explored variables measured using parent report, child report, and direct observation, which may be associated with parent report of such outcomes. The quality of parent-child interaction and its relationship with the outcomes was also investigated. Results: Part I showed that the proportion of children aged 2-12 years with one or more PCS was significantly higher in the mTBI group compared to the control group with a superficial injury to the head. Within the preschool age group, the proportion of children with PCS was comparable between injury groups. The likelihood of parent report of one or more PCS in children aged 2-12 years decreased if the child was female, and increased with multiple acute PCS, having a mTBI, and higher parental stress. Part II revealed that PCS in preschool children have been mostly assessed at an acute time point. Studies in the systematic review also revealed behaviour difficulties in preschool children even months post-injury. The systematic review highlighted several issues, including the lack of age-appropriate and validated PCS measures for preschoolers and the heavy reliance on parent report. In Part III, comparison of distributions based on mean ranks showed that the number of acute PCS that parents reported in the physical and sleep domains, as well as the mean acute PCS total scores, were significantly higher in preschool children with mTBI than those with limb injury (LI). The number of physical and sleep PCS significantly decreased over time in the mTBI group. The proportion of children with PCS was comparable between injury groups at each time point. Parents’ report of acute PCS was positively associated with pre-injury symptoms and child-rated acute pain. Parents’ report of PCS at one and three months post-injury was negatively associated with the number of acute physical signs of injury. With respect to behaviour outcomes, parent ratings of behaviour at pre- and post-injury were within the normal range and comparable between injury groups, except for sleep problems where the mTBI group received significantly higher ratings than the LI group at three months post-injury. However, this difference may have been pre-existing. Child behaviour at three months post-injury was significantly associated with premorbid child and parent variables: negatively associated with developmental status, and positively associated with parental stress and pre-injury behaviour. The quality of parent-child interaction was deemed suboptimal for most dyads and was significantly associated with several parent-rated variables: positively associated with child developmental status, and negatively associated with acute PCS, pre-/post-injury child behaviour, and parental stress. Conclusions: This thesis provided insight on the recovery of preschool children after mTBI, as well as on the potential benefit of monitoring children and providing additional support and psychoeducation to families post-injury. It also highlighted the need for additional research and demonstrated how future preschool mTBI studies may go beyond parent-rated measures of potential predictors to include novel factors, such as assessment of child’s pain and direct observation of parent-child interaction, which may offer unique information relevant to preschool mTBI outcomes.
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    Where stress presides: Investigating occupational stress within the Australian judiciary
    Schrever, Carly Anne ( 2023-08)
    Background: The thesis presents the first empirical research on the psychological health of the Australian judiciary. Judicial officers have an important and difficult job in democratic societies. They are senior members of the legal profession, the third arm of government, and guardians of the rule of law. They also manage demanding workloads, disturbing case material, and high-stakes decision-making. Several decades of Australian and international empirical research has demonstrated alarmingly high rates of stress and mental ill-health among lawyers and law students. However, judicial wellbeing has not received the same research attention, especially in Australia. The dearth of robust research impinges effective and evidence-based intervention to support judicial officers in their complex and critical work. Aims: The overall aim of this thesis was to empirically investigate the nature, prevalence, severity, sources and impacts of judicial stress in Australia. Across three studies, three broad research questions were addressed: (1) Are judicial officers stressed?; (2) Which judicial officers are most stressed, and why?; and (3) What are judicial officers’ perceptions of the sources and impacts of judicial stress, and their ideas for how judicial stress could be addressed? Method: Five Australian courts, from summary to appellate level, participated in the exploratory, mixed-methods research project. One-hundred and fifty-two (152) judicial officers participated in a survey, incorporating: validated measures for a broad range of stress constructs (non-specific psychological distress, K10; mental ill-health, DASS-21; burnout, MBI-GS; secondary traumatic stress, STSS; and alcohol use and dependence, AUDIT); a validated measure of workplace wellbeing factors (basic psychological needs satisfaction, BPNSFS); and several bespoke questions relating to subjective wellbeing and demographics. Sixty-one (61; 59 available for analysis) participated in in-depth interviews exploring the lived experience of judicial stress and ideas for court responses. Results: Study 1 found that, like lawyers, judicial officers reported elevated levels of psychological distress and problematic alcohol use, and that burnout and secondary trauma were prominent features of the judicial stress experience; however, unlike the broader legal profession, judicial officers’ reported levels of mental ill-health were relatively low. Study 2 found that judicial stress was highest in the high-volume, lower courts and that this was largely due to lower levels of basic psychological needs satisfaction within those jurisdictions. Study 3 found that workload and ‘stressors of injustice’ were emphasised as prominent and increasing sources of judicial stress, while the personal and professional satisfaction judicial officers derive from the work generally compensates for the stress they experience. It also found that increased time and committed leadership were seen as preconditions to the systemic enhancement of judicial wellbeing. Conclusion: The findings across the three studies suggest that: (1) judicial stress is high and increasing, and therefore urgent action is needed to address it – especially in the lower courts; (2) factors extrinsic to the judicial role are causing more stress than those intrinsic to the task of judging, suggesting that systemic stress mitigation is possible in the judicial context; (3) interventions directed to enhancing experiences of autonomy, relatedness, workload manageability, psychosocial safety, and effective leadership are likely to have the greatest impact on judicial wellbeing; and (4) with appropriate, evidence-based intervention to address the identified sources of judicial stress, marked improvements in judicial wellbeing can be expected.
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    Longitudinal prospective study of self-esteem and psycho-social function after childhood traumatic brain injury: delineating the contribution of injury, environmental, and individual factors
    Khan, Noor ( 2023-07)
    Background: Traumatic brain injury (TBI) is a significant public health burden that is a key contributor to lifelong disability. Such injuries can disrupt brain networks undergoing maturation during childhood and derail their ongoing development, contributing to profound changes in functioning. Sustaining a childhood TBI may also influence how individuals perceive themselves i.e., their self-esteem; however, current evidence base is weakened by retrospective, cross-sectional designs, and recruitment of heterogeneous samples. The overall aim of this prospective, longitudinal investigation was to examine the impact of paediatric TBI on self-esteem across childhood/adolescence and into young adulthood, and identify factors that contribute to individual variation in self-esteem. Method: The original study comprised 112 children and adolescents with mild-severe TBI (Anderson et al., 2013). For comparison, 43 typically developing controls matched on age, sex, and socioeconomic status were included. Participating families, both children and their parents, completed assessments at an outpatient clinic or at home at 6- and 12-months post-injury. At the 13-year follow-up time point, 29 young adults with childhood TBI and 10 typically developing controls were recruited from the existing cohort. Consenting participants completed questionnaires online. Results: As documented in three published and one submitted manuscript (chapters 6-9), findings revealed that some aspects of self-esteem may be especially vulnerable to deterioration following TBI. Specifically, perceived competence in both academic and behavioural domains was found to be significantly lower amongst children and adolescents with TBI, relative to typically developing controls. Individual variance in longitudinal self-esteem outcomes was documented in relation to injury factors (TBI severity, injury age, presence of frontal lobe pathology), environmental variables (parent mental health, family function, peer relations), and individual characteristics (social isolation, emotional wellbeing). For young adult survivors of childhood TBI, low self-esteem was endorsed by a sizeable proportion (approximately 20% or 1 in 5 TBI participants). Conclusions: Evidence for links between self-esteem and a multitude of injury, environmental, and individual factors accord with both developmental and brain-injury specific theoretical frameworks, and caution against exclusive reliance on injury-related variables when determining consequences of childhood TBI, especially in the context of self-esteem. While injury severity had some influence, environmental, and individual factors consistently made the largest and most significant contribution to global and domain-specific self-esteem. Collectively, results from the present investigation underscore the importance of routine and ongoing screening of non-injury, potentially modifiable risk factors, which likely represent useful targets for clinical interventions and rehabilitation programs seeking to optimise self-esteem in the short- and long-term following childhood TBI.
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    In the Image of Man: Understanding the Nature of God Beliefs and the Functions They Serve
    Susman, Michael James ( 2023-04)
    Despite the prevalence of religious belief and the way in which it permeates public life, psychological research into religion and belief in God has not met the size or complexity of the phenomenon. While a significant effort has gone towards understanding why some individuals are religious and others are not, relatively little focus and effort has gone towards understanding the variation between religious believers – a group that constitutes an overwhelming majority of the global population. The present thesis seeks to build a foundation on which a more nuanced and sophisticated investigation of religion can build, by focusing on the way in which individuals perceive and relate to God. This relational approach is built on the findings that suggest the way in which an individual perceives God is not merely a result of chance or culture, but instead reflects underlying needs and/or dispositions that are met by a God that is useful to a believer. This is done by first reviewing the current theoretical explanations of God beliefs and how it has been measured to date. Next, we provide three Studies in which God beliefs are predicted by personality traits. A functional account of this relationship is developed wherein we argue that these relationships exist because different Gods can meet different individual needs. Namely, we show that Compassionate people (an aspect of Agreeableness) tend to believe in Loving Gods and argue that this is because a Loving God meets their affiliative and support seeking needs. We also identify three personality aspects (Industriousness, Enthusiasm and Politeness) that negatively predict belief in a Punishing God, suggesting that this God is providing an externalised form of control. In Study 4 and 5, we then provide an assessment of previous God belief measures used to date and provide a series of theoretical tests of the arguments we have presented. We find that Loving God beliefs facilitate engaging in adaptive religious coping skills which lead to greater levels of life satisfaction. Across these five studies we find compelling evidence that God beliefs constitutes a fruitful and important area of future research. However, we show that for this to be fully realised a greater focus needs to be placed on appropriate measurement and theory. Further, we provide a theoretical framework built on the premises that (a) God belief is relational in nature and (b) Gods can serve multiple needs. Additionally, we provide evidence that the current theorising fails to capture the full breadth of God beliefs and suggest a framework for investigating these God beliefs.
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    Three Essays on the Psychological Micro-Foundations of Foreign Policy Attitudes
    Chagas Bastos, Fabricio Henricco ( 2023-06)
    This dissertation investigates the impact of deep-seated psychological constructs on individuals’ attitudes towards foreign policy. It consists of three research streams exploring personality traits, social dominance orientation (SDO), and disgust sensitivity. The findings provide valuable insights into the micro-foundations of foreign policy attitudes and their psychological underpinnings. The first research stream focuses on personality traits, examining their lower-level aspects/facets and their connection to foreign policy attitudes. Cooperative Internationalism (CI) is primarily influenced by openness, orderliness, enthusiasm, and compassion, with volatility acting as a limitation. Militant Internationalism (MI) is rooted in assertiveness and volatility, while politeness constrains MI attitudes. Isolationism (ISO) is negatively associated with Agreeableness and positively with Neuroticism, showing resistance to isolationism rooted in personality aspects favouring social engagement. Global Justice (GJ) shares a personality profile with CI but exhibits a negative effect of politeness due to its association with traditional moral values. The second research stream investigates SDO and its influence on foreign policy attitudes. Social Dominance Theory aligns with the findings, as the dominance dimension (SDO-D) underlies attitudes favouring the use of force abroad. It motivates dominant and aggressive foreign policies, but surprisingly, it is also associated with cooperative and redistributive stances. SDO-D predicts isolationism, highlighting its role in preserving power. The anti-egalitarian dimension (SDO-E) drives cooperative foreign policy attitudes and opposes redistributive strategies. The third research stream examines the influence of disgust sensitivity on foreign policy attitudes. Pathogen disgust sensitivity does not uniquely predict conservative foreign policy attitudes, contrary to prevailing notions. Sexual disgust, however, is associated with militant attitudes, potentially driven by a desire to protect societal norms. Individuals with high disgust sensitivity may perceive cooperative attitudes as risky, but the benefits of cooperation often outweigh their concerns. Overall, this dissertation contributes to understanding the complex interplay between deep-seated psychological constructs and foreign policy attitudes. Personality traits, SDO, and disgust sensitivity offer valuable insights into the formation of attitudes towards world politics. We provided the first integrative and systematic exploration into the relationships between psychological features underlying and foreign policy attitudes.
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    The fusion-secure base hypothesis
    Klein, Jack William ( 2023-07)
    Strong group commitments – such as identity fusion, a powerful form of group alignment – have historically been considered reliable predictors of intergroup violence. However, these aggressive outcomes are largely conditional on outgroup threat perception, with the effect of identity fusion on benign intergroup relationships underexplored. This dissertation outlines the fusion-secure base hypothesis, which leverages attachment theory, social identity theory, and identity fusion theory to argue that strong group commitments may engender trusting and cooperative intergroup relationships with non-threatening outgroups. However, when an outgroup is perceived as a threat, identity fusion will predict the violent outcomes for which it is well known. Chapter I introduces the theory via an historical example, the 1914 Christmas Truce, and presents the general structure of the dissertation. Chapter II outlines the theory in in detail, considers existing evidence, and dictates a research agenda, which is then pursued in Chapters III & IV. Chapter III describes a series of empirical studies that test the association between identity fusion and a willingness to trust and interact with outgroup members, and whether perceptions of a secure base mediate the relationship, with an internal meta-analysis supporting the unique suitability of fusion to engender positive intergroup relations. Chapter IV tests perceptions of outgroup threat as a moderator of the fusion-secure base hypothesis. This chapter explores intergroup relations in a complex and oft-violent social ecosystem, the Bangsamoro Autonomous Region in Muslim Mindanao (BARMM) region of the Philippines, by examining numerous intergroup dyadic relationships. Finally, Chapter V reflects on future research directions and considers the practical and theoretical implications of the theory. In summary, this dissertation proposes and explores a novel theory, the fusion-secure base hypothesis, and presents considerable theoretical and empirical evidence in its favour. This suggests that strong group commitments can help or hinder intergroup relations, depending on the context, and may represent both a cause and cure of sectarian violence.