Research master thesis | Developmental Psychopathology in Education and Child Studies (research) (MSc)
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Both youth with a substance use disorder (SUD) and youth who have experienced adverse childhood experiences (ACEs) show heightened vulnerability to psychopathology. We aimed to quantify the risk of...Show moreBoth youth with a substance use disorder (SUD) and youth who have experienced adverse childhood experiences (ACEs) show heightened vulnerability to psychopathology. We aimed to quantify the risk of comorbid disorders in SUD youth with ACE-history. Additionally, we aimed to examine relations between ACEs, overall household experience, and general distress. We used cross-sectional YIT-study data from interviews with Dutch youth (aged 16-22) upon SUD treatment entry for cannabis, alcohol, or stimulant use. We measured ACE-types experienced up until 15 years of age, past-year DSM-5 disorders, general distress (DASS-21), and overall household experience rating. Logistic regressions quantified relations between ACE sum score and anxiety, depressive, behavior, and any disorder. Higher ACE sum scores related to increased risks for a(n) anxiety (OR = 1.12, highest odds = 2.84; χ2(1) = 6.71, p < .010; Nagelkerke R2 = 0.2), depressive (OR = 1.21, highest odds = 5.43; χ2(1) = 18.11, p < .001; Nagelkerke R2 = 0.6), behavior (OR = 1.20, highest odds = 5.24; χ2(1) = 17.41, p < .001; Nagelkerke R2 = 0.6), and any (OR = 1.25, highest odds = 7.58; χ2(1) = 17.26, p < .001; Nagelkerke R2 = 0.7) disorder. Exploratory analyses revealed that frequency of parental fighting, being hit/abused, getting belittled, emotional neglect, physical neglect, insufficient household income, long parental sickness, and overall household experience positively related to DASS-21. In a hierarchical regression analysis with all ACEs and overall household experience, only emotional neglect related to DASS-21 (B = 3.68, t(373) = 2.41, p = .017). Overall household experience did not improve the model (F(12) = 3.51, p < .001; R2change < .001). In hierarchical regression analyses containing ACE sum score and overall household experience, overall household experience was not uniquely related to DASS-21 (t = -0.22, p = .824; R2change < .01). In conclusion, ACEs relate to comorbid disorders in SUD youth. Our exploratory research suggests that ACE frequency might influence this relation, while overall household experience does not further explain this relation. Further research should investigate which ACE measures (a.o., type, frequency) strongly relate to SUDs and psychopathology and examine improved treatment options.Show less
Research master thesis | Developmental Psychopathology in Education and Child Studies (research) (MSc)
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Theory of Mind (ToM) is a central topic in psychology and neuroscience. Nevertheless, debates persist regarding the validity and reliability of ToM measurement. Recent documentation of numerous...Show moreTheory of Mind (ToM) is a central topic in psychology and neuroscience. Nevertheless, debates persist regarding the validity and reliability of ToM measurement. Recent documentation of numerous failed replications in ToM research, involving both children and adults, highlights the need for establishing effective methods for measuring ToM across the lifespan. In response to this challenge, an international multi-lab collaboration named Many Babies 2 (MB2) has been launched, with Leiden University Babylab participating in this project. This thesis discusses preliminary findings related to the 16 adults tested at our lab. Following the MB2 protocol, an eye-tracker attached to a screen recorded participants’ looking behavior (first look [FL] and differential looking scores [DLS]) in an anticipatory looking task. We had two main goals. First, we aimed to find evidence of an automatic and implicit form of ToM in adults, by investigating whether participants’ looking behavior varied depending on a character’s mental state (i.e. whether the character was knowledgeable (condition 1) or ignorant (condition 2) about a specific situation). Contrary to our expectations, neither FL nor DLS differed between the experimental conditions. Second, we examined whether participants’ looking behavior was affected by (a) the selection of the anticipatory period, and (b) participants’ simultaneous activation of a conscious and explicit form of ToM, which had been measured with a debriefing questionnaire. We concluded that none of these factors significantly impacted participants’ looking behavior at a group level. However, FL and DLS of individual participants randomly varied when processed with different anticipatory periods; therefore, further research is needed to determine which anticipatory period minimizes the presence of noise in the data. While recognizing the preliminary nature of our findings, our insights contribute to the ongoing efforts to refine ToM assessment methods, underscoring the importance of addressing challenges in measuring this fundamental aspect of human cognition.Show less
Research master thesis | Developmental Psychopathology in Education and Child Studies (research) (MSc)
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Background: Empathy deficits are evident in Autism Spectrum Disorder (ASD) and Conduct Disorder (CD), and are linked to distinct brain structural abnormalities. Criticisms over the years highlight...Show moreBackground: Empathy deficits are evident in Autism Spectrum Disorder (ASD) and Conduct Disorder (CD), and are linked to distinct brain structural abnormalities. Criticisms over the years highlight that the DSM classifications of psychiatric disorders are primarily based on observable signs and symptoms, insufficiently based on causes and (neuro)biology, and rather ignorant of heterogeneity and overlap in symptoms. The current study therefore aimed for classification of ASD and CD in adolescents, based on brain morphology (BM) and social-emotional functioning (SEF). Methods: The sample included boys with ASD (n = 23) or CD (n = 51), and typically developing boys (TD; n = 36), aged 15-19 years. Participants’ empathy, aggression, psychopathy, problem behaviours, social function/cognition, and brain morphology (using an MRI scanning) were assessed. For the prediction of ASD and CD, a predictive regression with cross-validation comparing three models was performed, followed by several LASSO regressions. For clustering participants, K-means clustering was used with three clusters and K determined by the CH-index and ARI, followed by ANOVAs, T-tests and checking nestedness with crosstabs. Results: ASD and CD DSM-5 diagnoses can most accurately be predicted with a model based on SEF data, and least accurately with a model based on BM data. When using only SEF data, similar to the DSM, classification is erroneous in approximately one fifth of the participants. For an optimal prediction of ASD and CD, a combination of background, SEF, and BM variables is necessary. None of the cluster-solutions, theory-driven (three clusters) or data-driven (SEF data: four clusters; BM data: five clusters), were congruent with the original DSM clustering (ASD, CD, and TD). Conclusion: The current study shows that data-driven classification, based on BM and/or SEF, is not sufficiently accurate or congruent with the DSM classifications. This suggests that the DSM classifications, which are mainly based on SEF data, do not capture ASD and CD well enough. In order to better capture these disorders, combining factors across multiple domains (including background and BM data), is necessary. On top of that, this study shows less explored ways of analysing data in the field of social sciences. As such, this study may represent a stepping stone for the development of more accurate classifications with less negative implications.Show less
Research master thesis | Developmental Psychopathology in Education and Child Studies (research) (MSc)
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The number of Dutch children who require psychological help keeps growing, and therefore, it is essential to consider their perspective on improving their mental and physical health. The concept of...Show moreThe number of Dutch children who require psychological help keeps growing, and therefore, it is essential to consider their perspective on improving their mental and physical health. The concept of agency contributes to how children experience their health; allowing children to express agency can positively impact their well-being and increase their health (Robertson et al., 2015). The current study aimed to explore and map the role of agency and Emotion Regulation (ER) in children's (10-12 years) view on improving their mental and physical health. This was done using a thematic analysis process of the transcripts. The thematic analysis was conducted on data from previously conducted focus groups on children’s views on health. The results showed several vital themes identified from the data. The central concept of agency was found in children’s constant attempt/wish to change their feelings and thoughts. Within this central concept, three different approaches to ER were identified: “self-talk”, “practical solutions”, and “seeking support”. Especially “self-talk” was often mentioned by the children. The children's different approaches were found to be ways to apply one of three adaptive ER strategies: “reappraisal”, “acceptance”, or “problem-solving”. Children applied these strategies directly or indirectly. Although this study adds knowledge to the understanding of agency in children, much remains to be discovered about agency and its relationship with ER strategies. Follow-up research should be done to gain further insights into the role of agency in improving children’s health, with a particular focus on self-talk and seeking distraction.Show less
Research master thesis | Literary Studies (research) (MA)
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This study examines de Digitale Stad, or the Digital City, a pioneering virtual community in the Netherlands (1994-2001), as a metaphorical urban space. Drawing from urban theory, play theory and...Show moreThis study examines de Digitale Stad, or the Digital City, a pioneering virtual community in the Netherlands (1994-2001), as a metaphorical urban space. Drawing from urban theory, play theory and media theory, this thesis analyzes how users navigated and positioned themselves in the virtual realm. By focusing on DDS and the early Web, it sheds light on the Digital City's significance as an experimental space reflecting and influencing the evolving Dutch internet landscape.Show less
Research master thesis | Literary Studies (research) (MA)
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This study examines de Digitale Stad, or the Digital City, a pioneering virtual community in the Netherlands (1994-2001), as a metaphorical urban space. Drawing from urban theory, play theory and...Show moreThis study examines de Digitale Stad, or the Digital City, a pioneering virtual community in the Netherlands (1994-2001), as a metaphorical urban space. Drawing from urban theory, play theory and media theory, this thesis analyzes how users navigated and positioned themselves in the virtual realm. By focusing on DDS and the early Web, it sheds light on the Digital City's significance as an experimental space reflecting and influencing the evolving Dutch internet landscape.Show less
Research master thesis | Political Science and Public Administration (research) (MSc)
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The thesis examines European Union (EU) policies to address the gender pay gap (GPG) from 2006-2020. A detailed analysis of legislative and policy documents reveals the EU's active role in...Show moreThe thesis examines European Union (EU) policies to address the gender pay gap (GPG) from 2006-2020. A detailed analysis of legislative and policy documents reveals the EU's active role in promoting equal pay. The policies mainly reflect Human Capital Theory, Discrimination Theory, and Occupational Segregation Theory. The proposed actions aim to maximise women's human capital, address gender discrimination and overcome occupational segregation. However, the study identifies limitations in the conceptual frameworks, universalist approach, and lack of continuous monitoring. The research suggests the need for more specific policies, considering the diversity of women's needs, as well as dynamic monitoring mechanisms to adapt to the changing dynamics of the GPG. The thesis also challenges the limited definition of gender equality and suggests exploring additional factors to understand GPG comprehensively. In conclusion, while acknowledging the EU's commitment, the analysis reveals the need to evolve beyond traditional theories to address GPG more effectively.Show less
Research master thesis | Developmental Psychopathology in Education and Child Studies (research) (MSc)
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Coregulation does not seem to come naturally to children with autism spectrum disorder (ASD), putting them at risk of persistent emotional and behavioral dysregulation. However, little is known...Show moreCoregulation does not seem to come naturally to children with autism spectrum disorder (ASD), putting them at risk of persistent emotional and behavioral dysregulation. However, little is known about factors related to the ability of parents to provide coregulatory support and the responsiveness of children with ASD to their attempts. The current study used the state space grid (SSG) methodology to provide insight into the patterns of coregulation between twelve children with ASD (3-6 years) and their parent who spent most time with them (11 mothers, 1 father). In search of characteristics of children and parents that may hinder coregulation, the association with the severity of ASD symptoms and behavioral problems in children, as well as the self-regulation abilities, parenting stress and psychopathology in parents was examined. A free play task was used to elicit interactions between parents and children that were later coded for emotional engagement of both to measure coregulation. Child and parent characteristics were assessed by administration of the Autism Diagnostic Observation Scale (ADOS-2) to children and completion of the Child Behavior Checklist (CBCL), Behavior Rating Inventory of Executive Function for Adults (BRIEF-A), Parenting Stress Questionnaire (OBVL) and Brief Symptom Inventory (BSI) by their parents. Children with ASD generally had emotionally flexible interactions with their parents, indicating that they frequently changed between emotional engagement states when playing together. Their play interactions were mainly positive in nature and all parent-child dyads were able to repair the interaction following negativity or disengagement. More perceived externalizing behavior problems in children was related to less time to reengage in positive interactions with their parents and longer maintained mutual positivity. No association was found for the other characteristics of children and parents. These findings point to the added value of focusing in detail on parent-child interactions for future research and clinical practice.Show less
Research master thesis | Archaeology (research) (MA/MSc)
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In this study, five archaeological sites across the Netherlands from early medieval to early modern time periods were sampled to reconstruct past diet of the individuals found therein. The sites...Show moreIn this study, five archaeological sites across the Netherlands from early medieval to early modern time periods were sampled to reconstruct past diet of the individuals found therein. The sites chosen for the study were Alkmaar, Arnhem, Eindhoven, Klaaskinderkerke and Zwolle. The focus of the diet reconstruction was to analyze the childhood and adolescent diet using stable isotope analysis of carbon (δ13C) and nitrogen isotopes (δ15N). Through the use of tissues which are underutilized in archaeological diet reconstruction, dental enamel (en) and dentine (co) in conjunction, derived from second molars, it was possible to obtain isotopic ratios representative of childhood diet (enamel) and adolescent diet (dentine collagen). The results obtained were then used to analyze trends between the sites, between assigned sex and statistical relationships which served to provide grounds for further improvement of the methodology. Sampling and analysis of enamel was 100% successful, while sampling and analysis of collagen was 89% successful. The respective 76 and 68 samples were analyzed using a mass spectrometer and returned with reliable values. Results of intersite comparison aligned the, obtained results with past published literature regarding historical trends found in across the analyzed time periods, including increased consumption of marine fish in younger and more urban sites. Comparison of male and female assigned individuals has shown significant overlap between their values, suggesting that male and female individuals from the sites analyzed shared very similar diets during their childhood and adolescence. The investigation of isotope spacing of carbon values (Δen-co) allowed for determining that the diets of individuals analyzed was in large portion plant based, with significant inclusion of omnivore and marine foods as determined by isotopic ratios of carbon-13 and nitrogen-15. Analysis of statistical relationships between δ13Cen, δ13Cco and Δen-co has found a lack of correlation between δ13Cen δ13Cco, a positive correlation between Δen-co and δ13Cen and a negative correlation between Δen-co and δ13Cco. Follow-up studies should continue to investigate the recorded isotopic ratios in dental tissues, utilizing first and third molars as sources of further data capable of reconstructing sub-adult diet, as well as analyze local fauna to improve the accuracy of dietary reconstruction. The use of first and third molar isotopic ratios would also prove invaluable for investigating the statistical relationship between the tissues, due to the age of dental development and its relationship to diet reconstruction.Show less
Research master thesis | Archaeology (research) (MA/MSc)
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It is currently believed that there was no hominin presence on the British Isles during the Eemian interglacial stage, which lasted from 130 kya to 115 kya. However it is unclear what the reason...Show moreIt is currently believed that there was no hominin presence on the British Isles during the Eemian interglacial stage, which lasted from 130 kya to 115 kya. However it is unclear what the reason for this apparent absence is. This is especially the case considering that during the Eemian, temperatures in north-west Europe are known to have been several degrees warmer than even today, making it a potent habitat for early hominins. Several theories have existed in order to explain this, which include a complete absence in north-west Europe due to constraints in mental fortitude and an ecology that would have been unsuited for hominins to survive, as well as an early disappearance of the land bridge that connected France to Great Britain during the glacial periods. This was based on the fact that hominin sites that date back to the Eemian are exceedingly rare in north-west Europe, with the first examples only having been discovered relatively recently. This thesis aims to further explore these possibilities by making an ecological reconstruction of the site of Waziers, which is located in northern France and dates back to the Eemian. It does this based on carpological and palynological material that was found at the site. In addition to this a correlation of pollen records was made using several other Eemian type sites located in both France and Great Britain. This data is then combined with pre existing literature of other Eemian sites in north-west Europe with signs of hominin activity, in order to correlate these sites together so that Waziers can be placed in a wider chronological and climatological framework. In addition to this several other biological factors that were encountered at Waziers, are compared to the climatological conditions that were prevalent in the wider region as well. In doing so it was found the hominin activity that was detected at Waziers took place very early in the Eemian, when the stage had just transitioned from the Saalian glacial stage. In addition to this it could also be concluded that this early period was much warmer than originally anticipated. This could be seen in the presence of such indicator taxa as Lemna cf. minor, Hedera helix, and Salvinia natans, which could all be found within the vegetational record of the site. Because of these factors it is concluded that while there was already a hominin presence very early in the Eemian interglacial, which indicates that climatological conditions were at least adequate to sustain a hominin presence. It also shows that these hominins did not lack the mental fortitude to exist in these conditions, as was suggested by earlier theories. Despite this it is likely that, due to the high temperatures melting the land based ice locked in the glaciers during the Saalian, the land bridge that had existed between France and Britain during the glacial stage had already disappeared, inhibiting further hominin dispersal to the British Isles.Show less
Research master thesis | Archaeology (research) (MA/MSc)
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Diet has been one of the main drivers in the origin, evolution, and behaviour of our ancestors. Key moments in our evolutionary trajectory have been linked to changes in diet. These evolutionary...Show moreDiet has been one of the main drivers in the origin, evolution, and behaviour of our ancestors. Key moments in our evolutionary trajectory have been linked to changes in diet. These evolutionary developments include an increase in brain size, changes in habitat choice, adaptations in body size, and changes in life history. However, the Pleistocene archaeological record is highly fragmentary. To complement this lack of data, archaeology and ethnography have been combined for over decades. The predominant part of studies investigating early Homo subsistence behaviours and nutrition have focused on extant foraging populations from the African savannas to develop substantial models of human behavioural evolution. Though, studies focusing on hunter-gatherer nutrition have significantly undervalued the variability that is present within foraging diets. Furthermore, the rainforest-type environment is largely rejected its crucial role in the evolution of our lineage. The predominant part of studies have based their analyses on large-scale dietary indexes. Some authors have assumed that taken on aggregate, the average hunter-gatherer dietary profile can be recruited as a universal, ancestral diet. This led to the formation of the so-called Paleodiet movement, that attempts to help solve and understand public health issues known as the diseases of civilization such as obesity, diabetes, and other non-communicable diseases. However, it remains unclear what a uniform, ancestral Paleodiet should look like, or whether such a concept is feasible. Here, we show that hunter-gatherer nutrition is highly variable in nature, and that no uniformly applicable Paleodiet exists. By conducting a high-resolution macronutrient analysis on 30 wild edible plant taxa used by the Baka forager-horticulturalists from Southeastern Cameroon, we have shown that the nutritional qualities of wild edible plants are greatly affected by the effects of habitat and plant age, on a within- and between species level. Furthermore, we found that previously established aggregate hunter-gatherer nutritional profiles greatly differ from the reconstructed dietary- and macronutrient profiles established for the Baka. As Baka rainforest nutrition could be reverse-engineered, we illustrate that the Congo Basin rainforest-type environment provides enough macronutrients for hominins to sustain themselves without the aid of agriculture, and that the rainforest-type environment has been a crucial environment for the evolution of our lineage. Carbohydrates from starchy tubers are proposed to play a key role in Baka nutrition. Such underground storage organs are argued to have been important to early hominin nutrition within African rainforests. Public health studies may benefit by shifting their focus towards other components of Western lifestyle as more important contributors to diseases of civilization such as physical activity, stress, time spent outdoor, and overconsumption. We anticipate that future studies on extant foraging diet may greatly benefit from supplementing their use of large-scale hunter-gatherer nutritional indexes with high-resolution chemical nutritional data, as well as data 148 on weight of food brought back to camp, and estimated consumption patterns, to broaden our understanding on Pleistocene subsistence behaviour. We stimulate other research to partake in multi-disciplinary discourse for more increasingly diverse and inclusive narratives on human nutrition, Pleistocene subsistence behaviours, and human evolution. Lastly, to fully understand the influences of hominin dietary practices on the trajectory of our own evolution, it is imperative to acknowledge the plurality of both extant- and extinct hunter-gatherer lifeways, and to project a similar range of variability onto Pleistocene behaviours across different habitats.Show less
In 1895, the Dutch Social Democratic Workers’ Party (SDAP) convened for its first party conference. Two years later, the first SDAP members were elected to Parliament. Between these years and the...Show moreIn 1895, the Dutch Social Democratic Workers’ Party (SDAP) convened for its first party conference. Two years later, the first SDAP members were elected to Parliament. Between these years and the Second World War, the SDAP transitioned from a party with revolutionary aspirations to a fully normalized parliamentary entity. This thesis studies the SDAP’s assembly culture (vergadercultuur) in both the House of Representatives and their own party conferences. The first part of the thesis utilizes a combination of traditional and innovative digital methodologies to demonstrate that the normalisation of the position of the SDAP in the House of Representatives peaked in the mid-1920s. The second part of the thesis explores the development of the internal assembly culture of the SDAP, focusing on the role of the chairperson, procedures, time management, and usage of ‘persoonlijke feiten’, a phenomenon originating from Parliament. This section shows that while the internal assembly culture of the SDAP matured in many respects, this process was non-linear in many other respects, rendering the metaphor of maturation insufficient.Show less
Research master thesis | Developmental Psychopathology in Education and Child Studies (research) (MSc)
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This thesis is part of a multi-lab eye-tracking project investigating implicit Theory of Mind (ToM) in toddlers and adults (ManyBabies2). Given the recent number of unsuccessful replications in...Show moreThis thesis is part of a multi-lab eye-tracking project investigating implicit Theory of Mind (ToM) in toddlers and adults (ManyBabies2). Given the recent number of unsuccessful replications in this field, the focus of this thesis lies in investigating the impact of methodological considerations regarding data quality on the obtained results. Specifically, this thesis addresses differences in eye-tracking data quality (accuracy, precision, and data loss) between toddlers and adults. Further, it examines how differences in data quality (precision and data loss) affect the dependent variables in an anticipatory looking (AL) task to measure ToM, and whether the results of the AL task change by adjusting the parameters of a standard fixation classification algorithm (i.e., the Tobii I-VT filter) to account for low data quality. A total of 16 adults and 16 toddlers (N = 32) participated in the ManyBabies2 study at the Leiden University lab. The AL task included two test trials with an ignorance and knowledge condition, during which participants’ looking behavior (first look and proportion differential looking score [DLS]) was measured. The results showed a significant difference in average data quality between toddlers and adults, with toddlers having lower accuracy and precision and higher data loss than adults. Moreover, the results indicated that data loss significantly affects proportion DLS in the ignorance and knowledge condition. However, no differences in AL looking behavior were found between the Tobii I-VT default and adjusted parameters. The findings of this thesis emphasize the need for consistent reporting of data quality. Future research should conduct larger-scale studies to validate and expand upon the findings in this thesis, and focus on refining the fixation classification algorithm parameters of the Tobii I-VT filter to adjust for differences in data quality.Show less
In this thesis, the role of the night in Early Christianity is examined from the first century to 250 CE. What nocturnal worship meant and how early Christians gave meaning to the role of the night...Show moreIn this thesis, the role of the night in Early Christianity is examined from the first century to 250 CE. What nocturnal worship meant and how early Christians gave meaning to the role of the night in their practice, as well as how this was seen and interpreted by their Romans neighbours, is combined in this study to make the case for the inherent nocturnality of the early church, and promote increased research into the topic.Show less
