Melbourne School of Psychological Sciences - Research Publications
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ItemDevelopment and Psychometric Validation of the Mental Health-Related Barriers and Benefits to EXercise (MEX) Scale in Healthy Adults(SPRINGER, 2023-02-23)BACKGROUND: Physical exercise has been shown to reduce anxiety and depression symptoms, the most common mental health disorders globally. Despite the benefits of exercise in anxiety and depression, the symptoms of these disorders may directly contribute to a lack of engagement with exercise. However, mental health-related barriers and benefits to exercise engagement have not been addressed in quantitative research. We introduce the development and psychometric validation of the Mental health-related barriers and benefits to EXercise (MEX) scale. METHODS: Three samples were collected online prospectively (sample 1 n = 492; sample 2 n = 302; sample 3 n = 303) for scale refinement and validation with exploratory and confirmatory factor analysis. All participants were generally healthy adults, aged 18-45, and had no history of severe mental illness requiring hospitalization and no physical disability impacting over 50% of daily function. RESULTS: We identified a 30-item, two-factor model comprising 15 barrier and 15 benefit items. Overall model fit was excellent for an item-level scale across the three samples (Comparative Fit Index = 0.935-0.951; Root-Mean-Square Error of Approximation = 0.037-0.039). Internal consistency was also excellent across the three samples (α = 0.900-0.951). The barriers subscale was positively correlated with symptoms of anxiety, depression and stress, and negatively correlated with measures of physical activity and exercise engagement. The benefits subscale was negatively correlated with symptoms of anxiety, depression and stress, and positively correlated with measures of physical activity and exercise engagement. CONCLUSION: The MEX is a novel, psychometrically robust scale, which is appropriate for research and for clinical use to ascertain individual and/or group level mental health-related barriers and benefits to exercise.
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ItemHeterogeneity of quality of life in the later stages of first-episode psychosis recovery(SPRINGER, 2022-11-15)PURPOSE: First-episode psychosis (FEP) is characterised by wide heterogeneity in terms of symptom presentation and illness course. However, the heterogeneity of quality of life (QoL) in FEP is not well understood. We investigated whether subgroups can be identified using participants' responses on four QoL domains (physical health, psychological, social relationships, and environmental) 18-months into the recovery phase of FEP. We then examined the discriminant validity of these subgroups with respect to clinical, cognitive, and functioning features of FEP. METHOD: Demographic and clinical characteristics, QoL, cognition, and functioning were assessed in 100 people with FEP at the 18-month follow-up of a randomised controlled trial of Individual Placement Support, which aims to facilitate vocational recovery. QoL was measured using the World Health Organisation's QoL-BRIEF. A two-stage clustering approach using Ward's method and Squared Euclidean Distance with a k-means confirmation was conducted. Multinomial logistic regressions were used to establish external validity. RESULTS: Three QoL subgroups emerged: a 'good' subgroup with relatively high QoL across all domains (31%), an 'intermediate' subgroup with relatively low psychological QoL (48%) and a 'poor' subgroup with markedly low social relationship QoL (21%). Negative symptoms, depressive symptoms, social/occupational functioning, and social inclusion at follow-up predicted subgroup membership. Sensitivity analysis found similar results. CONCLUSION: Although some individuals with FEP have QoL comparable to individuals without mental ill health, QoL can remain concerningly low despite treatment efforts. Future research on interventions that target factors associated with poor QoL, such as low social inclusion, is required to counteract prolonged poor QoL in FEP.
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ItemSimplification Is Not Dominant in the Evolution of Chinese Characters.(MIT Press, 2022)Linguistic systems are hypothesised to be shaped by pressures towards communicative efficiency that drive processes of simplification. A longstanding illustration of this idea is the claim that Chinese characters have progressively simplified over time. Here we test this claim by analyzing a dataset with more than half a million images of Chinese characters spanning more than 3,000 years of recorded history. We find no consistent evidence of simplification through time, and contrary to popular belief we find that modern Chinese characters are higher in visual complexity than their earliest known counterparts. One plausible explanation for our findings is that simplicity trades off with distinctiveness, and that characters have become less simple because of pressures towards distinctiveness. Our findings are therefore compatible with functional accounts of language but highlight the diverse and sometimes counterintuitive ways in which linguistic systems are shaped by pressures for communicative efficiency.
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ItemParental personality and early life ecology: a prospective cohort study from preconception to postpartum.(Springer Science and Business Media LLC, 2023-02-27)Personality reliably predicts life outcomes ranging from social and material resources to mental health and interpersonal capacities. However, little is known about the potential intergenerational impact of parent personality prior to offspring conception on family resources and child development across the first thousand days of life. We analysed data from the Victorian Intergenerational Health Cohort Study (665 parents, 1030 infants; est. 1992), a two-generation study with prospective assessment of preconception background factors in parental adolescence, preconception personality traits in young adulthood (agreeableness, conscientiousness, emotional stability, extraversion, and openness), and multiple parental resources and infant characteristics in pregnancy and after the birth of their child. After adjusting for pre-exposure confounders, both maternal and paternal preconception personality traits were associated with numerous parental resources and attributes in pregnancy and postpartum, as well as with infant biobehavioural characteristics. Effect sizes ranged from small to moderate when considering parent personality traits as continuous exposures, and from small to large when considering personality traits as binary exposures. Young adult personality, well before offspring conception, is associated with the perinatal household social and financial context, parental mental health, parenting style and self-efficacy, and temperamental characteristics of offspring. These are pivotal aspects of early life development that ultimately predict a child's long-term health and development.
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ItemThe moral significance of prosstecting environmental and cultural objects(PUBLIC LIBRARY SCIENCE, 2023-02-09)A powerful avenue through which to promote the preservation of the natural and cultural environment is to afford cultural and environmental objects moral significance. In this research, we examine a range of factors that may give rise to moral concern regarding the protection of culturel and environmental objects as ends in themselves. In this way, we also extend theorizing and evidence beyond a focus on sentience as a focal determinant of moral significance Across five studies we show that non-sentient objects can sometimes be viewed as possessing intrinsically valuable properties that afford them moral standing (independent of their extrinsic/means-end value or any perception of their capacity to think and feel). People judge it morally wrong to harm things that are beautiful, sacred, rare, or old, and this cannot be explained merely by their usefulness or economic value. Our findings provide new insight into ways to elevate the protection of natural and cultural objects to an issue of moral significance, and suggest avenues through which to motivate the preservation of a natural and cultural environments.
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ItemHedonism as a motive for information search: biased information-seeking leads to biased beliefs.(Springer Science and Business Media LLC, 2023-02-06)Confirmation bias in information-search contributes to the formation of polarized echo-chambers of beliefs. However, the role of valence on information source selection remains poorly understood. In Experiment 1, participants won financial rewards depending on the outcomes of a set of lotteries. They were not shown these outcomes, but instead could choose to view a prediction of each lottery outcome made by one of two sources. Before choosing their favoured source, participants were first shown a series of example predictions made by each. The sources systematically varied in the accuracy and positivity (i.e., how often they predicted a win) of their predictions. Hierarchical Bayesian modeling indicated that both source accuracy and positivity impacted participants' choices. Importantly, those that viewed more positively-biased information believed that they had won more often and had higher confidence in those beliefs. In Experiment 2, we directly assessed the effect of positivity on the perceived credibility of a source. In each trial, participants watched a single source making a series of predictions of lottery outcomes and rated the strength of their beliefs in each source. Interestingly, positively-biased sources were not seen as more credible. Together, these findings suggest that positively-biased information is sought partly due to the desirable emotional state it induces rather than having enhanced perceived credibility. Information sought on this basis nevertheless produced consequential biased beliefs about the world-state, highlighting a potentially key role for hedonic preferences in information selection and subsequent belief formation.
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ItemE-cigarette product preferences of Australian adolescent and adult users: a 2022 study(BMC, 2023-02-01)BACKGROUND: Research that comprehensively documents preferences for different types of novel nicotine products in Australia is lacking, making it difficult for policymakers to determine where public health efforts should be focused. This study thus sought to explore Australian adolescent and adult e-cigarette users' preferences for different types of e-cigarettes and e-liquids. Purchasing behaviours and sources of e-liquid were also examined. METHODS: An online survey was administered to 4,617 Australians aged 12 + years, 636 of whom had used an e-cigarette in the last 30 days and were the focus of this study. Among users, 45% also smoked tobacco cigarettes, 41% were non-smokers, and 14% had never smoked. RESULTS: The majority (82%) of e-cigarette users surveyed reported using nicotine-containing e-liquid in their devices. Fewer (60%) reported using non-nicotine e-liquid. The preference for nicotine over non-nicotine e-liquid was observed among all age and smoking groups. Most users (89%) reported using flavoured e-liquids, with adolescents (96%) significantly more likely than young adults (90%) and adults aged 25 + years (85%) to report using such e-liquids. Fruit flavours were the most popular among all subgroups. In terms of device type, disposable e-cigarettes were the most common product used among almost all groups; the exception being adults aged 25 + years who preferred systems with refillable tanks. Friends and tobacco retailers were the most frequently nominated sources of nicotine e-liquid among adolescents and young adults. Among adults aged 25 + years, tobacco retailers and the Internet were the most frequently nominated sources of these products. CONCLUSION: Disposable e-cigarettes with flavoured, nicotine-containing e-liquid are popular among users of the devices, including adolescents. Measures that restrict the accessibility and availability of flavoured e-liquids and disposable e-cigarettes, and greater enforcement of laws regarding the sale and importation of nicotine e-liquids, are urgently needed to protect youth and never smokers from these products.
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ItemPosition representations of moving objects align with real-time position in the early visual response(eLIFE SCIENCES PUBL LTD, 2023-01-19)When interacting with the dynamic world, the brain receives outdated sensory information, due to the time required for neural transmission and processing. In motion perception, the brain may overcome these fundamental delays through predictively encoding the position of moving objects using information from their past trajectories. In the present study, we evaluated this proposition using multivariate analysis of high temporal resolution electroencephalographic data. We tracked neural position representations of moving objects at different stages of visual processing, relative to the real-time position of the object. During early stimulus-evoked activity, position representations of moving objects were activated substantially earlier than the equivalent activity evoked by unpredictable flashes, aligning the earliest representations of moving stimuli with their real-time positions. These findings indicate that the predictability of straight trajectories enables full compensation for the neural delays accumulated early in stimulus processing, but that delays still accumulate across later stages of cortical processing.
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ItemExamining the neural correlates of error awareness in a large fMRI study(OXFORD UNIV PRESS INC, 2022-03-03)Goal-directed behavior is dependent upon the ability to detect errors and implement appropriate posterror adjustments. Accordingly, several studies have explored the neural activity underlying error-monitoring processes, identifying the insula cortex as crucial for error awareness and reporting mixed findings with respect to the anterior cingulate cortex (ACC). Variable patterns of activation have previously been attributed to insufficient statistical power. We therefore sought to clarify the neural correlates of error awareness in a large event-related functional magnetic resonance imaging (fMRI) study. Four hundred and two healthy participants undertook the error awareness task, a motor Go/No-Go response inhibition paradigm in which participants were required to indicate their awareness of commission errors. Compared to unaware errors, aware errors were accompanied by significantly greater activity in a network of regions, including the insula cortex, supramarginal gyrus (SMG), and midline structures, such as the ACC and supplementary motor area (SMA). Error awareness activity was related to indices of task performance and dimensional measures of psychopathology in selected regions, including the insula, SMG, and SMA. Taken together, we identified a robust and reliable neural network associated with error awareness.
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ItemThe relationship between response dynamics and the formation of confidence varies across the lifespan(FRONTIERS MEDIA SA, 2022-12-15)Accurate metacognitive judgments, such as forming a confidence judgment, are crucial for goal-directed behavior but decline with older age. Besides changes in the sensory processing of stimulus features, there might also be changes in the motoric aspects of giving responses that account for age-related changes in confidence. In order to assess the association between confidence and response parameters across the adult lifespan, we measured response times and peak forces in a four-choice flanker task with subsequent confidence judgments. In 65 healthy adults from 20 to 76 years of age, we showed divergent associations of each measure with confidence, depending on decision accuracy. Participants indicated higher confidence after faster responses in correct but not incorrect trials. They also indicated higher confidence after less forceful responses in errors but not in correct trials. Notably, these associations were age-dependent as the relationship between confidence and response time was more pronounced in older participants, while the relationship between confidence and response force decayed with age. Our results add to the notion that confidence is related to response parameters and demonstrate noteworthy changes in the observed associations across the adult lifespan. These changes potentially constitute an expression of general age-related deficits in performance monitoring or, alternatively, index a failing mechanism in the computation of confidence in older adults.