Research master thesis | Psychology (research) (MSc)
closed access
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 | Archaeology (research) (MA/MSc)
open access
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 | 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)
under embargo until 2026-01-31
2026-01-31T00:00:00Z
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
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)
closed access
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
Between 1914 and 1940, the SDAP dominated municipal politics in Amsterdam. Buoyed with the introduction of universal male suffrage in 1917 and the expansion of municipal tax powers in 1920, social...Show moreBetween 1914 and 1940, the SDAP dominated municipal politics in Amsterdam. Buoyed with the introduction of universal male suffrage in 1917 and the expansion of municipal tax powers in 1920, social democratic aldermen such as Wibaut and De Miranda sought to establish a welfare municipality in the capital. Through the municipalisation of basic necessities, housework, and social hygiene, and the provision of care for the sickly, elderly, needy, and unemployed, the alderman hoped to provide for the material welfare and mental well-being of the working-class. Municipal Socialism in Amsterdam was seen as a unique project in the Netherlands. However, the municipal socialist project in Amsterdam was inherently dependent on acquiescence of bourgeois parties in Amsterdam and the confessional national government in The Hague, not to speak of global developments and the world economy. Relativizing the uniqueness of Amsterdam, Rotterdam and The Hague concurrently pioneered different aspects of municipal socialism in the face of similar shortcomings. Amsterdam’s greatest distinction was its incredibly effective advertisement of municipal socialism in publications throughout the interwar period, reinforced by the opposition it inspired in the national bourgeois press. Practically, while Amsterdam’s spending and earnings in municipal socialist fields was generally above average, the capital did not spend or earn significantly more than other social democratic municipalities across all municipal socialist fields. Nor did the capital significantly outperform the two other major municipalities in municipal socialist fields. Thus, while the municipal socialist project in Amsterdam may have financially been above average in the Interwar period, it was not unique, nor significantly different. However, we cannot deny the political and ideational impact of the municipal socialist project in Amsterdam on interwar political thought and post-war public memory.Show less
This thesis deals with binary gender roles in Revolutionary Nationalism in Post-Revolutionary Mexico. By analyzing the first 20 number of the Comic book Adelita y las Guerrillas, the thesis argues...Show moreThis thesis deals with binary gender roles in Revolutionary Nationalism in Post-Revolutionary Mexico. By analyzing the first 20 number of the Comic book Adelita y las Guerrillas, the thesis argues that masculine and feminine gender roles are created in tandem, primarily through the characters Adelita and Juan sin miedo. The thesis argues that whilst portraying progressive gender roles on a superficial level, at its core, the comic book reproduces conservative gender ideology as a part of Revolutionary Nationalism.Show less
Research master thesis | Psychology (research) (MSc)
closed access
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
Research master thesis | Developmental Psychopathology in Education and Child Studies (research) (MSc)
closed access
Prediction-based and repetition-based learning are two learning strategies, differing most profoundly in their depth of processing. In repetition-based learning, students repeat information shortly...Show morePrediction-based and repetition-based learning are two learning strategies, differing most profoundly in their depth of processing. In repetition-based learning, students repeat information shortly after learning it, while in prediction-based learning, students make a prediction before learning the information. This study aims to compare the effectiveness of the two learning strategies for memory recall, as well as consider the influence of age, the magnitude of the prediction errors, and the involved brain areas. It seeks to enhance the educational debate on these learning strategies by uncovering the strategies' mechanisms and guiding educators on their effective use. To accomplish this, 28 young adolescents and 46 young adults were scanned in an MRI scanner while learning numerical facts using both strategies: predicting and repeating. The study explored the influence of strategy, age group, and prediction error on memory recall. Furthermore, it investigated strategy-specific and age-specific differences in the medial temporal lobe (MTL), striatum, anterior cingulate cortex (ACC), and dorsolateral prefrontal cortex (DLPFC). While it was expected that prediction-based learning would result in better learning for both age groups as it requires deeper processing, results showed that adults had improved memory for repetition compared to prediction, whereas adolescents did not show a significant difference between the two learning strategies. Within prediction-based learning, adults showed increased memory for small and large prediction errors, while adolescents only did for large prediction errors. Lastly, among the investigated brain areas, the ACC, which is involved in error detection, showed the most prominent role in prediction-based learning.Show less
Research master thesis | Classics and Ancient Civilizations (research) (MA)
open access
This thesis explores the way women in selected Euripidean tragedies engage with verbal communication and proposes that this female verbal repertoire can serve as a foundation for a feminist...Show moreThis thesis explores the way women in selected Euripidean tragedies engage with verbal communication and proposes that this female verbal repertoire can serve as a foundation for a feminist interpretation of the respective plays. Female interaction with verbal communication can be separated into three distinct categories: a) silence, b) song, and c) speech. Following this categorization, this thesis firstly delves into specific verses from Medea (259-268) and Hippolytus (710-723, 800-805) to indicate that female tragic silence entails a skillful manipulation of speech. Secondly, verses from Medea (410-430) and two fragments from Hypsipyle (752h 3-9, 759a 80-89) are examined to demonstrate how female tragic song can function as a lyrical form of feminine language. Thirdly, Pasiphae’s apologia (472e 4-12, 34-41) in the Cretans is analyzed to pinpoint how female tragic speech can be rhetorically constructed, serving as a springboard for self-exculpation and female empowerment. Drawing from French feminism and American post-structuralist feminism, this study orchestrates a dialogue between the Euripidean corpus and (post) modern feminist theory and indicates how a reader-oriented approach to the ancient texts can both honor a historically grounded reception of tragedy and suggest how modern audiences can imbue classical tragic texts with fresh meaning.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Within negotiations individuals differ in their motivation to reach certain outcomes over others (outcome orientation). These differences may exaggerate as asymmetrical power dynamics impose...Show moreWithin negotiations individuals differ in their motivation to reach certain outcomes over others (outcome orientation). These differences may exaggerate as asymmetrical power dynamics impose disadvantageous conditions for some individuals within a group. As such restrictions may limit an individual’s ability to realise its interest in certain outcomes, individuals may evoke compensatory mechanisms to alleviate these disadvantages. Building on previous studies (Van Tol & Steinel, 2019), we propose that creative cognitions (e.g., flexibility or originality) may qualify as such potential compensatory mechanism. Consequently, we predict that the effect of individual outcome orientation in relation to an asymmetrical dispersion of power within groups may motivate compensatory engagements in creative behaviours that aim to alleviate the effects of disadvantageous situational constraints. To this end, 150 participants took part in a three-person fictious face-to-face online study. Participants were randomly assigned to either a powerful, powerless, or equal power condition, whilst further differentiations ensured individualistic and collectivistic outcome orientations. Upon reading the instructions, participants completed both a flexibility and an originality task. Results of a 2 (social motive: pro-social vs. pro-self) x 3 (relative power: powerless vs. equal power vs. powerful) ANOVA, as well as a 2 (social motive: pro-social vs. pro-self) x 3 (relative power: powerless vs. equal power vs. powerful) ANCOVA (with individual knowledge about cooking as covariate) revealed non-significant interaction effects for both flexible (ANOVA) and original (ANCOVA) compensation. Across the possible combinations of powerless and powerful, and pro-social and pro-self, participants did not differ in their creativity scores, disconfirming our hypotheses. As these null findings stand in direct contradiction to previous literature, the need for further investigation of creative cognitions in negotiations is highlighted.Show less
Research master thesis | Psychology (research) (MSc)
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Previous studies have highlighted the role of perspective giving in improving intergroup attitudes, particularly among disadvantaged groups. Building on this research, in the current study I...Show morePrevious studies have highlighted the role of perspective giving in improving intergroup attitudes, particularly among disadvantaged groups. Building on this research, in the current study I investigated how the content of perspective giving, focused on issues of inequality or harmony between groups, influences disadvantaged group members’ motivations for collective actions towards social change. I specifically examined this within the context of Cyprus focusing on the Turkish-speaking Cypriot minority (N = 161) in relation to the Greek-speaking Cypriot majority, using a vignette experimental approach. As hypothesized, I found that participants who focused on inequalities with the advantaged outgroup reported greater support for social change, collective action intentions, and change motivation compared to those who focused on commonalities with the outgroup. However, the expected interaction with perspective giving was not found, as it did not make a difference whether the participants gave their perspective to a member of the advantaged outgroup or did not. These findings contribute to our understanding of the complexities of intergroup dynamics and extend on the possible effects of perspective giving on collective action intentions.Show less
