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 | Psychology (research) (MSc)
open access
Bullying victimization is a major public health concern, because victims often experience long-term negative mental health outcomes. Longitudinal brain structure research in children is needed to...Show moreBullying victimization is a major public health concern, because victims often experience long-term negative mental health outcomes. Longitudinal brain structure research in children is needed to understand the possible mechanisms underlying the relation between bullying victimization and negative mental health outcomes. Previous research has shown that the fusiform gyrus, amygdala and vmPFC are impaired in victims. Therefore, this thesis examined the relation between victimization and fusiform gyrus, amygdala and vmPFC volume over time. We hypothesized that victims of bullying, compared to children uninvolved in bullying, would have a larger fusiform gyrus volume and a steeper volume increase. Furthermore, we hypothesized that victims of bullying, compared to children uninvolved in bullying, would have a smaller amygdala and vmPFC volume and a steeper volume decrease. The sample consisted of 156 children (62% female), aged between 7 and 9 years old at baseline, from the Leiden Consortium on Individual Development. At the beginning of the study, the Revised Olweus Bully/Victim Questionnaire was administered to measure bullying victimization and high-resolution structural MRI scans were taken. This was done again two years later. Children were classified as victims if they had been bullied regularly in the past two months. We did not find an effect of victimization on fusiform gyrus, amygdala and vmPFC volume. Future research examining the influence of victimization on both structural and functional brain development is needed to provide further insights, which can help inform the design of interventions to reduce the negative consequences of bullying victimization. The current findings emphasize the importance of protective factors that make a victim’s brain development resilient against victimization. This indicates a need for interventions targeting the development of social-emotional skills or the increase of family support.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Adolescence is characterized by the onset of puberty. Puberty, in turn is shown to be a driver of brain development and has been related to the onset and increase of internalizing symptoms. However...Show moreAdolescence is characterized by the onset of puberty. Puberty, in turn is shown to be a driver of brain development and has been related to the onset and increase of internalizing symptoms. However, the relationship between puberty, brain development, and internalizing symptoms has not been studied using multiple pubertal measures in both sexes. Here we examine the mediating role of brain development on the relationship between puberty and internalizing symptoms. Pubertal status, timing, age at menarche, and internalizing symptoms were assessed based on self-reports in 160 adolescents between 10 and 25 using a three-wave accelerated longitudinal design. Structural MRI scans were only obtained in the first wave. Subsequently, the relations between the pubertal measures (status, timing, age at menarche) and internalizing symptoms were tested as well as their relations with grey matter thickness and volume in frontal, cingulate, and subcortical areas. Only age at menarche as a timing variable had a significant effect on internalizing symptoms at T1 in girls (ß = -.36, p = .002, 95% CI [-.68, -.17]). Mediation models revealed no significant mediation of grey matter thickness and volume in our ROIs. Other effects did not reach significance or became non-significant after Bonferroni corrections. These findings indicate that menstruating before one’s peers is a risk factor for developing internalizing symptoms. This highlights the importance of supporting early menstruating girls to possibly prevent them from developing internalizing symptoms. Replication studies are needed to assess the accuracy of our results.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 | Psychology (research) (MSc)
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Building on evidence that minority representation increases minorities’ political participation, in my preregistered study, I investigated whether increased racial representation within the climate...Show moreBuilding on evidence that minority representation increases minorities’ political participation, in my preregistered study, I investigated whether increased racial representation within the climate movement causes Americans of color (N = 226) to evaluate the climate movement more positively and to encourage them to partake in climate activism. I tested this by using a 2 x 2 between-subjects design in which representation was manipulated both descriptively (i.e., the presence of people of color) and substantively (i.e., a focus on issues specifically affecting people of color) in a short video about climate activism. The results showed that descriptive representation had a positive, significant effect on evaluation of the movement, but no effects were found for substantive representation nor on climate action behavior. These findings enrich the scientific literature and provide insights on how social movements can become more inclusive, potentially increasing their effectiveness.Show less
Research master thesis | Psychology (research) (MSc)
under embargo until 2026-03-29
2026-03-29T00:00:00Z
Relevance: Efficacy of doctor empathy and nocebo education on treatment outcomes of people with cancer has been established across experimental and randomised-controlled trials (RCT). Objective: i)...Show moreRelevance: Efficacy of doctor empathy and nocebo education on treatment outcomes of people with cancer has been established across experimental and randomised-controlled trials (RCT). Objective: i) to test whether distinct effects of clinician empathy and nocebo information can also improve psychological and side effect outcomes of clinical advanced breast cancer patients undergoing chemotherapy and ii) to explore whether potential positive effects are persistent over treatment time. Methods: In this 2x2 proof-of-principle study, before treatment start, a total of 23 Dutch, chemonaïve, female breast cancer patients undergoing chemotherapy were randomised (1:1:1:1) to short information videos on chemotherapy side effects. The four videos varied on levels of empathy (+ / -) and nocebo information (+ / -). During treatment, participants’ psychological (primary outcomes: anxiety, distress) and side effect outcomes were assessed by self-report questionnaires at 7-days, 21-days, and 52-days after treatment start. Results: Repeated linear mixed model analyses indicated that empathy generally did not affect the level of anxiety (p = .440) or distress (p = .056). Empathy increased overall intensity (β = 0.76, 95% CI [.07; 1.44], p = .032) and number of side effects (β = 0.78, 95% CI [.11; 1.45], p = .025). Nocebo information did not seem to influence intensity (p = .269) or number of side effects (p = .975). Only anxiety levels were indicated to increase over time (p = .008), both at 21-days (β = 0.86, 95% CI [.25; 1.47]) and 52-days (β = 1.18, 95% CI [.38; 1.98]) post-treatment start. Conclusions: In clinical settings, advanced breast cancer patients may not profit from empathy or nocebo information. Repeating the study with a larger sample is recommended to gain clarity on communication effects. The information videos may benefit training of clinical staff and treatment consultations.Show less
Research master thesis | Psychology (research) (MSc)
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Cooperation and competition are important aspects of group behavior that have been well-researched in social psychology, but the relation between these elements has not been investigated to a...Show moreCooperation and competition are important aspects of group behavior that have been well-researched in social psychology, but the relation between these elements has not been investigated to a comparable degree. While competition between groups is known to increase cooperation within groups, the precise magnitude of its influence is not clear. Theoretically-relevant moderators that could influence this relationship have been left largely unexplored, and influential methods of studying cooperation and competition have not been assessed. Therefore, in this pre-registered meta-analysis, we investigated the impact of between-group interactions, including outright between-group competition and situations where groups compare their performance to other groups, on within-group cooperation. We conducted a systematic review of the literature involving economic games that compare cooperation in the presence of an intergroup interaction to cooperation within single groups. We compiled 17 relevant studies which yielded 47 effect sizes. Our multilevel random effects model revealed a small-to-medium, positive effect of intergroup interaction on within-group cooperation (g = 0.505, N = 4187). Confirmatory moderator analyses indicated that males, compared to females, invested more in within-group cooperation during intergroup interactions than in single, isolated groups. Additionally, effects involving intergroup comparison were weaker than effects featuring intergroup competition. Exploratory moderator analyses revealed that several variations in the methods of study impact the effect on within-group cooperation (e.g. deception, decision type, and participant matching). Our findings present compelling meta-analytic evidence that intergroup competition has a reliable impact on cooperation, and raises several opportunities for future research.Show less
Research master thesis | Psychology (research) (MSc)
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Avoidance is a hallmark symptom of Post-Traumatic Stress Disorder (PTSD), yet the link between avoidance learning and PTSD severity and treatment outcome has not yet been explored. For this purpose...Show moreAvoidance is a hallmark symptom of Post-Traumatic Stress Disorder (PTSD), yet the link between avoidance learning and PTSD severity and treatment outcome has not yet been explored. For this purpose, we administered a computer-based avoidance learning task to 144 treatment-seeking PTSD patients during the baseline assessment of a randomized clinical trial. The task consisted of a photo of blue or red colored lamps (conditional stimuli, CS+) followed by aversive photos (unconditional stimulus, US), while a photo of a yellow-colored lamp was followed by a black screen (safety stimulus, CS-). The US could be avoided by pressing a button during one CS+ (CS+ avoidable) but not the other (CS+ unavoidable). Participants were asked to fill in a threat expectancy rating after the CSs, and to report their relief after omission of the US. Participants were then given exposure therapy, and their PTSD symptoms were measured throughout 52 weeks. We predicted that higher rates of unnecessary or ineffective avoidance, higher expectancy ratings after omission of the US, and higher relief scores would relate to higher PTSD severity, and lower treatment gains. Results did not confirm any hypothesis; however, elevated threat expectancies (regardless of CStype) were related to PTSD symptom severity at baseline, and expectancies following CS- were related to PTSD severity across time points. Findings suggest general impairment in action-safety learning; however, it might be more relevant in light of PTSD severity to further explore the role of general threat expectancy. Furthermore, future studies should consider utilizing physiological measures, and adapting the task to include avoidance costs.Show less
Research master thesis | Psychology (research) (MSc)
closed access
In this study we investigated the relationship between stress, prosociality, and academic achievement. With a sample of UK-based college students, we aimed to investigate whether prosociality may...Show moreIn this study we investigated the relationship between stress, prosociality, and academic achievement. With a sample of UK-based college students, we aimed to investigate whether prosociality may serve as a buffer for the assumed negative relationship between stress and academic achievement. Our findings revealed that there was a negative relationship between academic stress and academic achievement. Furthermore, people tended to be more prosocial when they were stressed. However, this increased prosociality was not related to academic achievement and did not buffer people’s academic achievement from the negative effects of stress. The findings highlight the complex dynamic between stress, prosociality, and academic achievement. Understanding the interplay between these three variables has significant value for the innovation of interventions and preventive measures to enhance the overall well-being in students.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)
closed access
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 | 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 | Psychology (research) (MSc)
under embargo until 2026-02-27
2026-02-27T00:00:00Z
Food waste is a big problem in the Netherlands. In an effort to find a solution to this problem, the present study examines the influence of expiration date labels on people’s intention to waste...Show moreFood waste is a big problem in the Netherlands. In an effort to find a solution to this problem, the present study examines the influence of expiration date labels on people’s intention to waste food. The current phrase “ten minste houdbaar tot” [“at least preservable until”] can be seen as definitive and thought to refer to food safety whereas it refers to food quality, thus this study proposes an alternative phrase “beste kwaliteit voor, vaak goed na” [“best quality before, often good after”]. The aim of this alternative phrase was to make clear that the expiration date refers to food quality and that the food could still be safe to consume after this date had passed. Participants were presented with dairy and pantry products that had an expiration date that had passed by five days. This expiration date was shown with the current phrasing or the alternative phrasing. Results showed that the alternative phrase led to a lower intention to waste dairy compared to the current phrase. Whereas for pantry products, there was no difference in intention to waste food between the two phrases. Moreover, results showed that the intention to waste dairy was mediated by perceived risk. Meaning that dairy products that were presented with the alternative phrase were perceived as less risky to consume, which in turn was associated with a lower intention to let the product go to waste when the expiration had passed. Thus, changing the phrasing of the expiration date label could help in reducing food waste in the Netherlands.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 | Psychology (research) (MSc)
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Language control in bilingual speakers involves effectively switching between languages, inhibiting the non-intended language, and continuously monitoring speech errors. It has been a matter of...Show moreLanguage control in bilingual speakers involves effectively switching between languages, inhibiting the non-intended language, and continuously monitoring speech errors. It has been a matter of controversy concerning whether language control operates in a comparable manner to cognitive control processes in non-linguistic domains (domain-general) or if it is exclusive to language processing (domain-specific). Midfrontal theta oscillations have been considered as an index for increased cognitive control, so examining whether a similar midfrontal theta effect is likewise evident in bilingual language will bring new insights to the ongoing debate. This study aimed to explore midfrontal theta oscillations in bilingual control with a specific focus on three fundamental control processes: language switching, inhibitory control, and speech monitoring. We reanalysed the EEG data obtained from two previous language switching studies where Dutch-English bilinguals named pictures based on colour cues. Theta power increase was observed during language switching, specifically in switch trials compared to repeat trials, and this effect was observed in the midfrontal region. Similarly, enhanced midfrontal theta power was observed during error monitoring, specifically when participants failed to select the intended language at a switch, compared to correct responses. However, no midfrontal theta effect was found during inhibitory control, reflected by a missing modulation in switch trials following a short run (i.e., a short sequence of same-language repeat trials) compared to a long run (i.e., a long sequence of same-language repeat trials). These findings largely support the involvement of domain-general cognitive control mechanisms in language control, particularly in language switching and speech monitoring, whereas inhibitory control remains unclear.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Mobile applications with a virtual coach providing real-time relapse-prevention support may be useful to aid smoking cessation as they are easily accessible, cost-effective, and can be utilized...Show moreMobile applications with a virtual coach providing real-time relapse-prevention support may be useful to aid smoking cessation as they are easily accessible, cost-effective, and can be utilized directly in situations where the risk of relapse is high. This study aimed to examine the effect of three types of relapse-prevention support on tobacco craving to inform the development of a mobile application with a virtual coach. The three types of support focused on (A) motivation and self-efficacy; (B) one’s future self and implementation intentions; and (C) identity-related positive self-talk. Secondly, the study aimed to explore how physical nicotine dependence related to the effect of relapse-prevention support on tobacco craving. A virtual reality experiment with a within-participant design was conducted where 25 participants intending to quit smoking were immersed in a virtual high-risk-of-smoking environment. The participants had four conversations in a randomized order with a concept version of a virtual coach on a simulated mobile phone: three conversations containing a type of relapse-prevention support and one neutral conversation. Physical nicotine dependence was measured at baseline and craving was measured after each conversation. Participants indicated that they would find it reasonably difficult to refrain from smoking in the VR environment and sense of presence was sufficient. Results indicated that the relapse-prevention support did not decrease craving compared to neutral contact with the coach. Furthermore, no association was found between physical nicotine dependence and effect of relapse-prevention support. These results stress the need for evaluations of effectiveness in order to inform the further development and improvement of the relapse prevention support prior to finalizing a mobile application with a virtual coach.Show less
Research master thesis | Psychology (research) (MSc)
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The present research investigated the association between Machiavellianism and different behavioural responses in a novel economic game. The main purpose of the research was to reveal the patterns...Show moreThe present research investigated the association between Machiavellianism and different behavioural responses in a novel economic game. The main purpose of the research was to reveal the patterns of behaviours associated with the Machiavellian personality in a setting in which acting in a cooperative and competitive manner are both feasible options.The results of the research suggest that there is a negative association between Machiavellianism and cooperation. Individuals with higher level of Machiavellianism tended to invest more resources to competition, relative to cooperation. No association was found between Machiavellianism and choosing peace in the economic game. Lastly, performance in the game could, also, not be predicted by one’s Machiavellian inclinations. We can conclude that, even when given the possibility to compete and cooperate at the same time, Machiavellians still tend to exhibit a higher propensity towards non-cooperative responses and a slightly higher propensity towards competitive behaviours compared to low Machiavellians.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
Research master thesis | Psychology (research) (MSc)
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Poverty in the UK has increased, particularly after the Covid-19 pandemic. To prevent people from falling into a poverty trap, it is important to understand how financial scarcity affects financial...Show morePoverty in the UK has increased, particularly after the Covid-19 pandemic. To prevent people from falling into a poverty trap, it is important to understand how financial scarcity affects financial decisions involving risks. This topic lacks consensus in the literature with some authors arguing for a tendency towards more risk-taking, while others arguing for more risk aversion. This study posits that the risk tendency is influenced by frames of gains and losses. More specifically, financial scarcity leads to more risky choices in the domain of losses (H1), whereas it leads to less risky choices in the domain of gains (H2). People in financial scarcity tend to experience negative affect that impacts their cognitive systems, leading to more reliance on System 1 thinking, which exacerbates biases, such as the reflection effect. To test the hypotheses an online survey was conducted and 200 participants from the UK were recruited via Prolific Academic. The participants were divided into two groups for the manipulation of financial scarcity using the household task. Half of the participants were in the debts condition (financial scarcity), whereas the other half were not (control). Subsequently, all participants were presented with six risky choices, where they had to choose one of two options (one risky, the other conservative) framed in both gains and losses and three combinations of probabilities. Results from a Generalized Mixed Model showed that the cognitive bias associated with the reflection effect was found to be equally present in everyone and was more pronounced for more extreme probabilities (e.g., 10%/90% and 20%/80%), but not for moderate probabilities (e.g., 40%/60%). Thus, the expected interaction between debts and frames was not confirmed. It is suggested that future studies use an intuitive decision-making manipulation with more extreme probabilities (e.g., 1%/99%), consider a field risk manipulation, an incentivized lottery and the same expected value within and between probabilities at the lottery.Show less
