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 | Psychology (research) (MSc)
closed access
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)
closed access
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)
closed access
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 | 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 | 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 | 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)
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 | 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 | 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)
closed access
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
Research master thesis | Psychology (research) (MSc)
closed access
Adolescents with ADHD partake in risk-taking behavior (RTB), such as risky driving or unsafe sex, more often than their peers. Because RTB is strongly related to risk perception and RTB takes place...Show moreAdolescents with ADHD partake in risk-taking behavior (RTB), such as risky driving or unsafe sex, more often than their peers. Because RTB is strongly related to risk perception and RTB takes place in a group of peers, it is important to gain a better understanding of risk perception in a social context. First, this study investigated whether adolescents with ADHD are more susceptible to 1) peer influence only and 2) peer influence and presence on a behavioral level. Further, we examined the neural responses to these two social manipulations. We examined whether peer attachment acted as a buffer against susceptibility. Finally, we adopted a continuous approach of ADHD and examined the link between inattention symptoms and hyperactivity-impulsivity symptoms and susceptibility to peer influence and presence. Adolescent boys (ages 13-23) with ADHD (n = 46) and without ADHD (n = 57) performed a risk rating task with a behavioral part and an fMRI-scanner part. The scanner part included highly believable virtual peer influence and peer presence manipulations. For our fMRI analyses we selected regions of interest that are implicated in the social brain (TPJ and dmPFC), the reward processing network (VS, Insula and vmPFC), and the cognitive control network (dlPFC). All adolescents showed equal susceptibility to peer influence only. Similarly, all adolescents showed a higher susceptibility to peer influence and presence. We found no effects on susceptibility of clinical diagnosis, inattention or hyperactivity-impulsivity symptoms or peer attachment. Our fMRI results showed effects in the TPJ. First, peer influence only elicited less activation in the bilateral TPJ for adolescents with ADHD. Second, activity in the left TPJ elicited by peer influence and presence was stronger for adolescents with weaker peer attachment. Together, these findings indicate that peer influence and presence may partly cause increased RTB in adolescence. However, increased RTB in adolescents with ADHD cannot be explained by increased susceptibility peer influence and presence. These findings provide an opportunity to decrease excessive RTB through increasing resistance to peer influence and presence in interventions for adolescents in general.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Novelty can be defined as a motivationally and attentionally salient learning signal. Past research has found benefits of novelty to include increased plasticity and enhanced memory encoding....Show moreNovelty can be defined as a motivationally and attentionally salient learning signal. Past research has found benefits of novelty to include increased plasticity and enhanced memory encoding. Briefly exposing subjects to a novel stimulus or environment in place of an expected threat has also been shown to enhance the extinction process following fear conditioning in both rodents and humans. This is important, as the treatment for trauma-based disorders such as post-traumatic stress disorder (PTSD) has only been demonstrated effective for up to 66% of those affected and a dysfunction in the fear extinction process appears central in the development and continuation of such disorders. The current study explored whether replacing a fear-inducing stimulus with a novel visual stimulus resulted in more effective fear extinction, as quantified using both subjective and objective parameters, namely subjective arousal, and pupil dilation. In addition, a condition with olfactory novelty was included to explore the effects of contextual novelty on preventing the reinstatement of the conditioned fear 24 hours following fear conditioning. The study successfully established fear conditioning using threatening visual stimuli in a classical conditioning paradigm. However, there was no support for novelty-enhanced fear extinction, nor for the benefit of olfactory novelty on the retention of fear extinction 24 hours post-extinction. Rather, an increase in pupil dilation in the context of a novel olfactory environment was found especially in conditions where a fear-inducing unconditioned stimulus had been paired with a novel replacement stimulus, possibly suggesting a contextual novelty-induced fear reinstatement effect.Show less
Research master thesis | Psychology (research) (MSc)
closed access
While the traditional bystander effect literature suggested that the presence of bystanders leads to less help provided to the victims, recent studies that focused on dangerous incidents provided...Show moreWhile the traditional bystander effect literature suggested that the presence of bystanders leads to less help provided to the victims, recent studies that focused on dangerous incidents provided evidence for decreased or even reversed bystander effect in the presence of bystanders. Although previous research proposed that the heightened arousal experienced by bystanders during dangerous incidents with in-group victims leads to increased assistance, empirical evidence supporting this claim remains limited and difficult to be studied with self-report measurements. This study addresses these limitations by employing the biopsychological model of challenge and threat (BPS-CT) to examine empirically the physiological reactions of bystanders. Participants were exposed to vignettes describing dangerous and non-dangerous incidents involving in-group and out-group victims, while their cardiovascular activity and blood pressure were measured. The presence of bystanders was found to have a marginal impact on reducing threat among bystanders, irrespective of the incident's severity. Moreover, in dangerous incidents, the presence of other bystanders and a shared in-group identity with the victim heightened participants' sense of challenge. The findings align with previous meta-analytic evidence, highlighting that bystanders are more likely to intervene in dangerous situations. The results are discussed and possible implications are proposed for designing intervention programs aimed at increasing bystander intervention rates.Show less
Research master thesis | Psychology (research) (MSc)
closed access
This study investigated the impact of parental verbal threat (vs. safety) information regarding a stranger on a child’s subjective and behavioral fear responses towards that stranger. As a...Show moreThis study investigated the impact of parental verbal threat (vs. safety) information regarding a stranger on a child’s subjective and behavioral fear responses towards that stranger. As a manipulation, parents were instructed to provide their children (N=79), aged 10-14 years, with standardized verbal threat or safety information about two strangers in the lab. Then, children engaged in a social interaction task with the two strangers (blind to their condition) separately, while child behavioral avoidance was recorded. Following the task, children reported fear beliefs for each stranger. Also, parents completed a self-report questionnaire on social anxiety symptoms. Children reported more fear beliefs for the stranger paired with the threat information, but no significant difference was found in observed avoidance. In addition, verbal threat information did not have a stronger influence on children’s observed avoidance in case of higher reported fear beliefs. Similarly, high parental social anxiety symptoms did not moderate the impact of verbal threat information on the child’s cognitive or behavioural fear indices. However, they did have a significant influence on behavioural avoidance, regardless of verbal information. Overall, this study shows a causal effect of verbal threat messages provided by parents only on child subjective fear and highlightsthe need for further research on the verbal transmission of childhood social fears in the context of family, by examining these processes in various social situations, age groups, and fear indices.Show less
Research master thesis | Psychology (research) (MSc)
open access
Human decision-making in the context of value-based learning considerably deviates from the premise to always maximise short-term reward. This sort of behavioural variability has been attributed to...Show moreHuman decision-making in the context of value-based learning considerably deviates from the premise to always maximise short-term reward. This sort of behavioural variability has been attributed to exploration during the choice process and has been linked to the locus coeruleusnoradrenaline (LC-NA) system. A recent computational account implementing a “noisy” reinforcement learning (RL) model provides evidence that computational imprecision during the learning process contributes to behavioural variability in decision-making as well. In the present study, the role of the LC-NA system in modulating learning imprecision has been investigated, using a multi-modal approach including the newly developed noisy RL model, a double-blind pharmacological manipulation, and EEG. The responses of thirty participants in a decision-making task were investigated during two experimental sessions in which either atomoxetine, a NA reuptake inhibitor, or placebo was administered, and the model fit of the noisy RL model was tested against the classical RL model without learning imprecision parameter. Contrary to our expectations, we did not find evidence for a modulatory role of the LC-NA system of learning imprecision. However, in line with our expectations, increased NA levels did not impact exploratory behaviour either. Crucially, the noisy RL model outperformed the classical RL model assuming exact learning and learning imprecision led to a significant number of non-maximising decisions contributing to behaviour variability. Moreover, the exploratory EEG analyses on potential underlying mechanisms of learning imprecision suggest learning noise to emerge broadly during feedback processing, rather than within a certain time window. The current study provides further evidence for the importance of computational imprecision during value-based learning.Show less
