Melbourne School of Psychological Sciences - Theses

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    Metacognition in decision making: Exploring age-related changes in confidence
    Overhoff, Helen ( 2022-11)
    Metacognition is a fundamental human function that supports goal-directed behaviour. By constantly monitoring and evaluating our decisions we are able to detect errors when they occur and adjust the behaviour accordingly. Metacognitive evaluations can be expressed in ratings of decision confidence or error detection reports. Humans are generally capable of forming well-calibrated estimates of their own performance, yet metacognitive abilities have been shown to be specifically affected by healthy ageing. However, the mechanisms underlying this decline remain poorly understood. This thesis aims to investigate the cognitive processes of age-related changes in perceptual metacognitive performance by combining approaches from the fields of error monitoring and decision confidence. For this, we developed a new paradigm for studying the metacognitive evaluation of errors and correct responses that was feasible for adults of all ages. While recording an electroencephalogram (EEG) and response force, a sample of 65 healthy adults from 20 to 76 years made a series of decisions in a modified version of the Flanker task and subsequently indicated how confident they felt about their decision on a four-point scale. Across two studies, conducted in the same large sample, I addressed three specific research questions: first, how is metacognitive performance affected by healthy ageing? Second, what are factors contributing to the observed decline in metacognitive performance? And third, how does an age-related decline in metacognitive performance affect subsequent behaviour? The analysis of behavioural data (Study 1a) showed that metacognitive accuracy declined significantly with older age and that this decline could not be explained by the decline in task performance alone. Independent of age, however, participants adjusted their performance according to their metacognitive evaluation of their previous decision and responded more cautiously after reporting low confidence. The analysis of electrophysiological data (Study 1b) focussed on the modulation of two correlates of error monitoring by confidence and age. The results indicated that the error/correct positivity (Pe/c), a component discussed as a marker of error detection and decision confidence, scaled with reported confidence in errors but did not show the expected modulation by age. The amplitude of the error/correct negativity (Ne/c), a marker of early error monitoring processes, also scaled with reported confidence in errors, but in contrast, was less sensitive to variations in confidence with older age. Finally, Study 2 investigated the effect of age on the relationship between confidence and two response parameters of the initial decision: response time and response force. We replicated a widely reported negative relationship between confidence and response time. Importantly, we showed, for the first time, that confidence was also negatively related to fine-grained changes in peak force, which was intuitively exerted by the participants. Notably, these associations were dependent on the accuracy of the response and changed markedly across age: the relationship between confidence and response time was only found in correct responses and was pronounced with older age, while the relationship between confidence and peak force was only found in errors and only in younger adults. Overall, these findings jointly provide novel insights deepening our understanding of the observed decline in metacognitive performance with older age. A similar modulation of the Pe/c by confidence across the lifespan suggests that the post-decisional process of accumulating evidence about the correctness of a prior decision might generally be intact until old age. Instead, the age-related decline in metacognitive accuracy appears to be related to a multitude of cognitive and neural changes, which might reflect increased noise and hence higher uncertainty in older adults’ computation of confidence. Moreover, I discuss how a metacognitive decline could manifest in real life and how recent findings offer a promising view regarding the effect of training on metacognitive performance.
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    Metacognitive Decisions on Decision Accuracy: Confidence Judgment and Changes of Mind
    Ko, Yiu Hong ( 2022-12)
    Even in the absence of external feedback, humans are capable of subjectively estimating the accuracy of their own decisions, resulting in a sense of confidence that a decision is correct. While decision confidence has been proposed to be closely related to other metacognitive judgments, including error awareness (i.e., awareness that a decision error has occurred) and changes of mind (i.e., reversal of previously made decisions), their relationships so far remain unclear. The current project aimed to investigate how confidence could be related to metacognitive judgments from two perspectives. First, Studies 1 and 2 investigated how confidence and changes of mind were affected by changes in different stimulus properties, particularly absolute evidence strength. In a brightness judgment task, participants were presented with two flickering, grayscale squares and required to select the square that appeared brighter. After each trial, participants reported their subjective accuracy on a rating scale ranging from “surely incorrect” to “surely correct”. Results showed that with stronger absolute evidence (i.e., increased overall luminance across both squares), confidence was increased and the proportion of changes of mind trials was reduced. These consistent changes support the hypothesis that higher confidence could contribute to less frequent changes of mind. Second, Study 3 investigated the relationships between confidence and the event-related potential (ERP) components of the centro-parietal potential (CPP) and the error positivity (Pe), which have been respectively proposed to be indexes of pre- and post-decisional evidence accumulation processes. In the same brightness judgment task, it was found that the relationships between confidence and these two ERP components depended on decision accuracy: Confidence was positively related to CPP amplitudes in correct trials, but negatively related to Pe amplitudes in error trials. These findings suggest that confidence in correct and error decisions involves different pre- and post-decisional processes. Overall, the current findings suggest that (a) confidence could serve as a basis of changes of mind, and (b) confidence in correct and erroneous decisions was differentially related to pre- and post-decisional ERP indexes of evidence accumulation. Taken together, they suggest that confidence might emerge during decision formation and could, with the contribution from post-decisional processes, serve as a basis of changes of mind.
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    Trait Regulation: Variability in Agentic Personality Expression and Its Implications for Behavior Change
    Rebele, Robert ( 2022)
    Despite the long-term stability of personality traits, several lines of research suggest that people might want to express different traits at different levels at different times. Drawing on perspectives from personality dynamics and self-regulation, I propose that people want to exercise at least some degree of agency over their short-term personality expression. This thesis presents two foundational investigations—one empirical and one theoretical—to evaluate this proposal. In Chapter 2, I discuss results from four empirical studies that consistently show that people hold “trait regulation goals (TRGs)” to intentionally influence their short-term personality expression. People often set TRGs to express the typically more desirable end of each trait continuum—but these preferences vary substantially depending on the context (i.e., TRGs co-vary with dynamic situational and motivational factors) and the individual (i.e., based on one’s general disposition toward that characteristic). In light of this evidence that people want to regulate their short-term trait expression, I next turned to the question of how they might do so. In Chapter 3, I present an extensive review of potential trait regulation processes, viewed through the lens of how they could be used to inform the design of behavior-change interventions. I define trait regulation as the psychological process of expressing preferred personality characteristics, and I discuss how processes that explain temporary shifts and enduring changes in trait expression could be used to improve the design of interventions to intentionally influence behavior. Taken together, this thesis makes the case for greater integration between research on personality dynamics and various forms of self-regulation, in hopes that doing so might help us better understand how we can help people express the full richness of their personalities.
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    The Cognitive and Neural Mechanisms of Dietary Decision-Making
    Schubert, Elektra ( 2022)
    Dietary decisions are influential on both physical and mental health. Unhealthy choices can have many negative consequences, including obesity, heart disease, diabetes, and cancer. This thesis investigated the role of tastiness and healthiness in dietary decisions and interventions, with three specific research questions. The first involved neural representations of tastiness and healthiness: more specifically, how these attributes are represented in the brain during the early stages of dietary decisions. The second question was centred on whether health warning labels (HWLs) can reduce sugary drink consumption. Finally, the third question involved how the experience and regulation of incidental emotions impacts dietary decisions. These questions were addressed in the three empirical chapters of this thesis. In Study 1, we investigated neural representations of tastiness and healthiness during the first second of rating food images (Experiment 1) or consumption decisions (Experiment 2). The results showed that fine-grained taste and health ratings could be decoded from electroencephalography data using multivariate pattern analysis. This suggests that during dietary decisions, tastiness and healthiness representations are present in the brain from an early stage, even without explicit instructions to consider them. In Study 2, we investigated whether HWLs encouraged healthier choices regarding sugar-sweetened beverages. In a laboratory-based task, participants viewed HWLs, then indicated their willingness to consume various beverages. The HWLs referred either to consequences of a poor diet (general) or sugary drinks (specific). The results showed that both types of HWLs decreased willingness to consume drinks, compared to a control condition. For general HWLs, this effect was weaker for drinks perceived as healthy, whereas the effect of specific HWLs remained constant regardless of perceived healthiness. Overall, our results suggest that HWLs may be effective at prompting behaviour change, and product-specific messages may reduce consumption of a wider range of drinks. In Study 3, we examined how dietary decisions are influenced by emotions and the regulation of these emotions. Participants completed an online task which involved experiencing and regulating emotions before making hypothetical dietary decisions. The results showed that negative emotions decreased willingness to consume foods, whereas positive emotions led to an increase, particularly for healthy foods. Regulating negative emotions did not change dietary decisions; however, actively increasing and decreasing positive emotions via reappraisal led to respective increases and decreases in desire for food. These results may suggest that people appraise stimuli in a way that matches their emotional state (e.g., feeling positive leads people to view foods as more pleasant). Overall, these findings highlight the importance of both healthiness and tastiness for dietary decision-making, support the effectiveness of HWLs for promoting healthier choices, and deepen our understanding of the effects of incidental emotions and emotion regulation on dietary decisions. This thesis may inform interventions to improve dietary decisions, and provides a strong basis for future studies that aim to evaluate interventions through examining changes to neural representations of taste and health attributes.
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    The P-word: Power aversion and responsibility aversion as explanations for the avoidance of power
    Hull, Kathryn Elizabeth ( 2022)
    Though we typically think that power is desirable, individuals will sometimes avoid power. One explanation for this is some individuals are averse to the responsibility associated with power. However, people may also avoid power because they perceive it as being inherently negative. This is supported by research on lay theories of power, which suggests that those who hold the coercive lay theory perceive powerful people as manipulative and deceitful. In this thesis, we propose a new theory of power aversion that expands on the coercive lay theory to explain how negative perceptions of power cause some individuals to avoid it. We propose that some power-averse individuals believe that possessing power will turn them into immoral, cold, selfish, and unjust people. We also suggest a convergence between research on responsibility aversion and lay theories of power, in that responsibility aversion is a consequence of the collaborative lay theory. This thesis develops individual difference measures for power aversion and responsibility aversion. It then assesses those measures against power avoidance, demonstrating they are both meaningfully related to power avoidance. Finally, we test the relationships between power aversion, responsibility aversion, the coercive lay theory, and the collaborative lay theory. The results of this study are contrary to initial hypotheses, suggesting that the coercive lay theory and responsibility aversion are positively related. Throughout this entire thesis, the relationship between power aversion and responsibility aversion is explored. Findings suggest that these two constructs are difficult to distinguish from each other and could be one in the same.
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    The neurobiology of error awareness and its role in adaptive behaviour
    Dali, Gezelle ( 2022)
    The ability to detect performance errors is imperative to ongoing and future goal-directed behaviour. Reduced error awareness has been found to be associated with diminished insight and limited functional recovery in a number of clinical conditions underpinned by dopaminergic dysfunction (e.g., attention-deficit/hyperactivity disorder, schizophrenia, substance use disorder). Despite the clear rationale for addressing these deficits, error awareness and its role in adaptive behaviour remains to be fully elucidated. Specifically, theories on the neural correlates of error awareness are somewhat incomplete. Further, it is unknown what role error awareness affords in adaptive behaviour and whether deficient error awareness – as observed in clinical disorders – compromises performance and results in increased error commission. This thesis addresses these questions over four empirical studies. Study 1 was designed to verify the robustness of previous neuroimaging findings by examining the neural correlates of error awareness in a large community-based sample (n = 402). Studies 2 and 3 investigated the role of error awareness in adaptive behaviour. In Study 2 this was achieved across two experiments which explored the relationship between error awareness and post-error slowing under dynamic conditions, while Study 3 determined whether error awareness facilitates learning from errors. Finally, Study 4 aimed to clarify whether chronic cannabis users exhibit reduced error awareness and whether this impairs learning from errors. More broadly, this study sought to determine the consequence of attenuated error awareness on adaptive behaviour. The current findings indicate that aware errors are accompanied by significantly greater activity than unaware errors in a subset of neural regions, including the insula cortex, anterior cingulate cortex (ACC), supramarginal gyrus and supplementary motor area. With regard to post-error adjustments, the results indicate that error awareness and post-error slowing are largely unrelated. Post-error accuracy was, however, found to be related to error awareness. More specifically, error awareness was predictive of performance such that aware errors were more frequently followed by correct inhibitory performance. This was not related to changes in reaction time but appeared to be a context-specific adaptation that was dependent on awareness. While these results were found to replicate in Study 4, no difference in error awareness and learning from errors was found between chronic cannabis users and controls. There was, however, evidence to suggest that age of first use and the level of cannabis-use related frequency and harm, may predict a compromised ability to learn from aware errors. Taken together, this thesis has clarified the neural correlates of error awareness and has provided insight into the adaptive function of error awareness. When considering each study concurrently, it is apparent that further work is required to improve the assessment of error awareness, particularly for use with clinical samples. Additionally, there remains the need to establish the precise role of dopamine in error awareness, and the direction of relationships between insula and ACC activity, autonomic responses and error awareness. Addressing these persisting questions may provide a greater understanding of the executive functions underlying goal-directed behaviour and inform the treatment of conditions underpinned by impaired error awareness.
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    Obsessive-Compulsive Traits and Eating Disorders: The Role of Cognitive Style, Socio-Emotional Functioning, and Autistic Traits
    Giles, Sarah Elizabeth ( 2022)
    Obsessive-compulsive traits, such as cognitive inflexibility, attention to detail, and deficits in socio-emotional processing are prominent features of eating disorders (EDs). These traits also mirror the cognitive and socio-emotional style of autism spectrum disorders (ASD), suggesting ASD traits may play a role in EDs. What remains to be seen is how socio-emotional and cognitive functioning influence the development and maintenance of ED symptoms, and the extent to which these traits impact treatment outcomes. This thesis comprised five studies investigating socio-emotional and cognitive functioning in EDs and their impact on treatment outcomes. Study 1 investigated the psychometric properties of the Detail and Flexibility Questionnaire (DFlex) (Roberts et al., 2011), a self-report measure of cognitive inflexibility and attention to detail, including confirmatory factor analyses (Nowakowski et al., 2013), internal consistency, and discriminant validity estimates were conducted in three participant groups: (1) individuals with a current or historical diagnosis of an ED (n = 124), (2) current or historical diagnosis of an anxiety disorder and/or depression (n = 219), and (3) individuals from the community (n = 852). The convergent validity of the DFlex was assessed through comparisons with Autism Quotient (AQ; Baron-Cohen et al., 2001), the Wisconsin Card Sorting Test (WCST; Grant and Berg, 1948; Heaton and Staff, 1993) and the Group Embedded Figures Test (GEFT; Witkin et al., 1971) within a combined ED and community sample (N = 68). Test-retest reliability of the DFlex was also assessed across 2 years in a community sample (N = 85). The CFA results did not support the original factor structure of the DFlex. A shortened version, DFlex-Revised, was developed and its factor structure, internal consistency, and discriminant validity were supported within the ED, anxiety/depression, and community groups. There was mixed support for convergent validity between the DFlex and the AQ, and no evidence of convergent validity between the DFlex and performance-based measures of set-shifting or detail processing. The results did not provide evidence of acceptable two-year test-retest reliability, cautioning the use of this measure across extended assessment intervals. The findings of Study 1 provided support for the factor structure and internal consistency of the DFlex-Revised in ED, anxiety/depression, and community groups, and suggest the DFlex-Revised has good discriminant validity within both ED and anxiety/depression samples. Study 2 comprised two studies, 2a and 2b, which both used path analyses to examine potential mediators in the relationships between cognitive and socio-emotional processes and ED symptoms in a sample of N = 401 participants (100% female, Mage = 20.07 years, SD = 4.99 years) recruited from a university and the community. Study 2a sought to expand our understanding of the vulnerability traits outlined in the cognitive-interpersonal model (Treasure and Schmidt, 2013) by examining the relationships between attention to detail and cognitive rigidity as assessed by the DFlex (Roberts et al., 2011), alexithymia as assessed by the Toronto Alexithymia Scale (TAS-20; Bagby et al., 1994), and ED symptoms as assessed by the Eating Disorder Examination Questionnaire (EDE-Q; Fairburn and Beglin, 2008). It was hypothesised that alexithymia would mediate the relationships between attention to detail and cognitive rigidity to ED symptoms. The findings of this study showed that the TAS-20 difficulties identifying feelings scale was the only significant mediator between attention to detail and cognitive rigidity to ED symptoms, suggesting attention to detail and cognitive rigidity may be associated with higher ED symptoms when coupled with difficulties identifying feelings. Study 2b investigated intolerance of uncertainty as assessed by the Intolerance of Uncertainty Scale (IUS; Buhr and Dugas, 2002), and orthorexia symptoms, as assessed by the ORTO-Revised (Rogoza and Donini, 2020), as potential mediators of the relationship between ASD traits indexed by the AQ total score (Baron-Cohen et al., 2001), and ED symptoms as assessed by the EDE-Q (Fairburn and Beglin, 2008). Results showed that ASD traits were not directly associated with ED symptoms but were indirectly related to ED symptoms through both intolerance of uncertainty and orthorexia symptoms. Although cross-sectional, these results support the notion that ASD traits may increase the vulnerability for disordered eating through their associations with other vulnerability traits such as intolerance of uncertainty and the development of problematic eating behaviours typical of orthorexia. Study 3 sought to enhance our understanding of the interplay between obsessive-compulsive traits and ED symptoms in a clinical ED sample, by conducting a network analysis of retrospectively assessed childhood obsessive-compulsive personality disorders (OCPD) traits and current ED symptoms in a combined anorexia nervosa (AN) and bulimia nervosa (BN) sample. Participants were 320 young adult women (Mage = 28.39 years, SD = 9.80) recruited from four European countries (United Kingdom, Austria, Spain, and Slovenia) as part of the multicentre European Healthy Eating Project. Participants completed the semi-structured EATATE interview (Anderluh et al., 2003) to retrospectively assess OCPD traits in childhood, and the Eating Disorder Inventory-2 (EDI-2; Garner et al., 1982) to assess current ED symptoms. Results revealed that the EDI-2 subscales of ascetism, social insecurity, ineffectiveness, and impulsivity were the most central nodes in the OCPD-ED network, while the EDI-2 interpersonal distrust subscale emerged as a bridging symptom connecting the OCPD and ED trait/symptom clusters. These findings highlight the centrality of non-specific ED symptoms in the ED symptom network and suggest that interpersonal distrust may play a functional role through which childhood OCPD traits and ED symptoms are connected. Given the importance of non-specific ED symptoms in Study 3 and the importance of cognitive inflexibility in AN more broadly, Study 4 used network analysis to examine the symptom network between these constructs and investigated whether cognitive flexibility connected ED symptoms to depression and anxiety symptoms. Participants were N = 193 patients (95.6% female, Mage = 26.89 years, SD = 9.45 years), referred for assessment and treatment at the Body Image and Eating Disorders Treatment and Recovery Service (BETRS) at St Vincent’s Hospital Melbourne. Participants completed the Cognitive Flexibility Scale (CFS; Martin and Rubin, 1995) to assess cognitive flexibility, the Depression, Anxiety and Stress Scale (DASS-21; Lovibond and Lovibond, 1996) to assess anxiety and depression, and the EDE-Q (Fairburn and Beglin, 2008) to assess ED symptoms at intake into the BETRS. Results showed that weight and shape concerns, assessed through the EDE-Q, were the most central nodes within the network, while cognitive flexibility emerged as a bridging node connecting ED symptoms to anxiety and depression. The findings may suggest that addressing cognitive flexibility could be a useful target to address psychological comorbidity within AN. Finally, Study 5 investigated the associations between ASD traits and the vulnerability traits of interest (i.e., cognitive rigidity, attention to detail, and alexithymia), and whether these traits were associated with psychological functioning and outcomes within a clinical ED sample recruited from the Peter Beumont Service in New South Wales. Participants were N = 85 individuals (92.9% female, Mage = 29.41 years, SD = 10.47 years) who completed the DFlex (Roberts et al., 2011) to assess attention to detail and cognitive rigidity, the TAS-20 (Bagby et al., 1994) to assess alexithymia, and the AQ (Baron-Cohen et al., 2001) to assess ASD traits. Participants also completed the Hospital Anxiety and Depression Scale (Zigmond and Snaith, 1983) to measure anxiety and depression symptoms, the Eating Disorder Quality of Life Scale (EDQLS; Adair et al., 2007) to assess quality of life, and the EDE-Q (Fairburn and Beglin, 2008) to assess ED symptoms. The results demonstrated that at intake into the Peter Beumont Service, ASD traits were significantly positively associated with attention to detail, cognitive rigidity, alexithymia, anxiety, and depression symptoms, and negatively associated with quality of life and confidence to change ED behaviours. However, ASD traits were not associated with ED symptoms at intake, nor were they associated with clinical outcomes for EDs following treatment. While limited by the small sample size, these findings may suggest that ASD traits contribute to the exacerbation of vulnerability factors that maintain the ED (such as low motivation to change ED behaviours, anxiety, depression, attention to detail, cognitive rigidity, and alexithymia) rather than directly affecting ED symptoms. To conclude, the results of this thesis highlight the presence and importance of impairments in cognitive and socio-emotional functioning within EDs. These vulnerability traits intersect in complex ways, with the impact of cognitive style and socio-emotional difficulties on ED symptoms being particularly pronounced when combined. This thesis has highlighted the importance of assessing the nature and impact of cognitive and socio-emotional characteristics in EDs, and the meaning individuals with EDs make of their experiences. Furthermore, the presence of comorbid anxiety and depression symptoms played an important role in the relationship between these vulnerability traits and ED symptoms, and future research examining the longitudinal relationships between these factors is sorely needed.
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    Characterising Choices and Response Times in Decisions from Experience with Perceptual Tasks
    Lin, Deborah Jingfen ( 2022)
    Often, everyday decisions that people face do not entail explicitly stated reward distributions and instead require learning about the decision environment from experience. At a fundamental level, these decisions require people to navigate a trade-off between exploration (i.e., trying out different options) and exploitation (i.e., sticking with a familiar option) to continually learn about and maintain an accurate representation of the environment in order to maximise reward. While research in this area has primarily focused on pure economic tasks where participants choose between gambles and obtain a reward, many choices people make involve integrating sensory information with economic value. For example, people might consider the overall ripeness of fruits on offer, how likely it is to obtain a good selection of ripe fruits and the price when deciding between shopping at one grocer over another. This thesis explores the effect of perceptual information and reward on behaviour in decisions from experience. The first section of this thesis examines these effects using a novel experimental paradigm in which participants repeatedly choose between two perceptual tasks that vary on perceptual uncertainty and reward in both stable and changing decision environments. In particular, I characterise participants' choices to stay on the current task or switch to the alternative task and their response times. The second section of this thesis establishes the presence of individual differences in learning and the treatment of perceptual uncertainty. In the final section of this thesis, I draw upon the fields of perceptual and economic decision making to develop a reinforcement learning diffusion model for sequential decisions involving perceptual uncertainty and reward.
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    Experiences and Outcomes of Weight Stigma Among Sexual Minority Men
    Austen, Emma Frances ( 2022)
    Sexual minority men may be particularly vulnerable to weight stigma and its outcomes due to the potent appearance pressures they face; however, most research has examined weight stigma among samples of heterosexual women. Thus, this thesis sought to comprehensively examine the experiences and outcomes of weight stigma among sexual minority men. Chapter 1 examined whether sexual minority men are more vulnerable to weight stigma across two studies, finding that gay and bisexual men internalize more weight stigma than heterosexual men, and, in one study, that bisexual men reported more frequent experiences of weight stigma than gay and heterosexual men. Chapter 2 built on these findings by modelling the longitudinal relationships of weight stigma with psychological wellbeing and body mass index among nearly 3000 sexual minority men. Results revealed that weight stigma relates to these outcomes in a feedback loop, with internalized weight bias predicting weight gain and poorer psychological wellbeing, and vice-versa, over time. Chapter 3 qualitatively examined the unique attitudes that may account for sexual minority men’s increased vulnerability to weight stigma. Across 17 individual interviews, sexual minority men discussed the immense value of appearing masculine (i.e., visibly muscular) within the gay community. Fatness was constructed in opposition of this masculine ideal; thus, participants suggested fat men may be undesired within the gay community because they are perceived as less masculine. Chapter 4 complemented the empirical findings of the previous chapters, commenting specifically on the limited conceptual clarity within weight stigma research and how it may be remedied in future studies. Together, this thesis provides valuable insight into the nature of weight stigma among sexual minority men, finding that sexual minority men (1) are more vulnerable to weight stigma than heterosexual men, (2) report poorer mental health after internalizing this stigma, and (3) may be particularly vulnerable to weight stigma because of the immense value associated with appearing masculine within this population. This thesis illustrates the importance of broadening the demographic scope of weight stigma research and highlights sexual minority men as a population worth prioritising in future studies.
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    Understanding Interference and Decision-Making in Recognition and Source Memory
    Fox, Julian William ( 2022)
    Recognition memory, or the ability to identify previously-experienced events, is an integral part of declarative episodic memory and of human cognition in general. Our understanding of recognition has undergone many developments over the past century, yet there are several aspects regarding its underlying mechanisms and its relation to other forms of episodic memory that remain uncertain. Specifically, there is a lack of certainty regarding: (a) the predominant causes of forgetting in recognition; (b) the ways in which retrieval can negatively impact subsequent retrievals in recognition; and (c) the relationship between recognition memory and source memory (i.e., the ability to identify the source/context in which an item was initially observed). In the present thesis, three studies were devised to investigate each of these issues. Study 1 investigated whether forgetting in recognition is primarily driven by interference from other study list items (i.e., item-noise), or interference from pre-experimental memories (i.e., context-noise and background-noise). Data from a list length experiment and subsequent fits using variants of the Osth, Jansson et al. (2018) global matching model revealed that item-noise is the predominant cause of forgetting in recognition, contradicting prior investigations (e.g., Osth & Dennis, 2015b) that suggested a dominance of background-noise. Study 2 investigated whether declines in recognition performance as a result of retrieval are primarily due to: (a) an increase in item-noise as additional items are stored in memory; (b) changes in the mental context used to cue memory that decrease the accessibility of studied items (i.e., context drift); or (c) an increasing prioritization of speed over accuracy as testing progresses. Data from a continuous recognition experiment and subsequent fits using further variants of the Osth, Jansson et al. (2018) model established that retrieval-induced forgetting in recognition is primarily attributable to both item-noise accrual and context drift, contradicting prior investigations that suggested a minimal role of item-noise accrual (e.g., Osth, Jansson et al., 2018). Study 3 investigated whether it is possible to retrieve the source of an item if the item itself is unrecognized. Across three pairs of experiments, it was ultimately demonstrated that source memory is, in fact, possible for unrecognized items. Importantly, this finding was shown to be highly subtle and was more easily detected when uncertainty in the participant-level data was accounted for with hierarchical Bayesian signal detection models. Across these studies, the thesis provides a rich understanding of the mechanisms underlying recognition and source memory, highlighting the unique and important contributions from diverse factors such as: item-noise, proactive interference, context drift, response bias, and the speed-accuracy trade-off. Moreover, the thesis discusses how future investigations into the cognitive mechanisms of recognition memory would benefit by substituting the randomly generated representations that are common in global matching models (e.g., Osth, Jansson et al., 2018) with realistic representations for items and contexts, thus allowing for highly constrained predictions at the single item level.