Neural gain is the mechanism underlying the stability/flexibility trade-off, which is fundamental for goal-directed yet adaptive behavior. Inspired by the development of a computational model that...Show moreNeural gain is the mechanism underlying the stability/flexibility trade-off, which is fundamental for goal-directed yet adaptive behavior. Inspired by the development of a computational model that estimates gain, we assessed whether people rationally modulate gain to demands for stability and flexibility. We designed two task-switch digit-classification experiments with 60 participants each, in which we manipulated the proportion incongruency (PI) in experiment one and cue-to-stimulus interval (CSI) in experiment two. Our results indicated that PI manipulation did not significantly affect gain, yet incongruency costs and switch costs demonstrated an increase in stability in response to high PI. CSI manipulation significantly affected both gain and incongruency costs, demonstrating increased flexibility in response to a short preparation time. Furthermore, we used questionnaires to assess participants' ASD and ADHD trait scores and tested whether these predicted biases in gain and/or impairments in gain modulation. Despite the lack of conclusive findings, this study offers insight in the relation between ASD and ADHD and neural gain. More studies that overcome our limitations may discover the impairments in neurocognitive mechanisms underlying psychological disorders and inform treatment. Altogether, our results indicate that people rationally adapt to demands for stability and flexibility following an antagonistic trade-off. Therefore, this study contributes to the research on neuromodulation and adds to the general understanding of attention. Our findings may also help to inform applied research on the benefits and drawbacks of stability and flexibility in the workplace. Thereby, managers could be made aware of the number of tasks assigned to their employees and whether the demand to switch between them is proportional to their difficulty.Show less
The digitalisation of political expression impacted social movement organisation. The global proliferation of information and communication technology (ICT) digitalised social movements towards...Show moreThe digitalisation of political expression impacted social movement organisation. The global proliferation of information and communication technology (ICT) digitalised social movements towards networked collective action. This fuelled the optimism about ICTs as liberalisation tool. Yet, authoritarian regimes showed increasing sophistication in digital repression which urges to investigate the link between digital repression (DR) and mobilisation. I use complementary insights from connective action theory and disconnective action theory to address the research question: What is the effect of DR on mobilisation? By arguing DR is multi-dimensional, the goal of this analysis is to establish the relationship between DR and mobilisation in authoritarian regimes. To this end, I conduct a systematic, global analysis. With an OLS regression, my large-N study analyses authoritarian regimes from 2000 until 2021. The findings are qualitatively supported with two case studies to address endogeneity concerns. On the one hand, I expect a prevention effect on mobilisation if DR is performed as long-term information manipulation. On the other hand, I hypothesise an escalation effect on mobilisation if DR is executed in form of a short-term information vacuum. Though the results are mixed, I conclude that there is initial support for both prevention and escalation effect of DR. I derive that DR is multi-dimensional and can prevent, but also escalate mobilisation.Show less
Grapheme-colour synaesthesia is a phenomenon in which presentation of letters and numbers are automatically associated with colours, and these associations stay consistent over time. Synesthetes...Show moreGrapheme-colour synaesthesia is a phenomenon in which presentation of letters and numbers are automatically associated with colours, and these associations stay consistent over time. Synesthetes have been found to show advantages in certain learning and memory tasks, such as language learning. Non-synesthetes have been seen to be able to create synaesthesia-like associations through repeated reinforcement between letters and colours. In this study, it was investigated if synaesthesia training in a native language could expedite the learning of a foreign alphabet. Additionally, it was hypothesised that allowing participants to choose their own letter-colour associations rather than being given predetermined associations would further improve their performance on the language learning task. To investigate this, two groups underwent synaesthesia training, with one group choosing their own associations and one group being given predetermined associations. The two groups then went through the same language learning task, where they were taught letters in a foreign language. The results showed that synaesthesia training expedited the learning of a new alphabet. The self-selecting group showed better consistency in their letter-colour associations than the group that had been pre-assigned colours. However, the learning rate of the self-selecting group was not significantly higher. To conclude, the study showed that synaesthesia training can have a positive effect on language learning, and different ways of training synaesthesia have distinctive effects on letter-colour consistency.Show less
Replication is an essential concept in psychological science. It can give rise to new insights into promising scientific developments, ensuring the quality and reliability of scientific research....Show moreReplication is an essential concept in psychological science. It can give rise to new insights into promising scientific developments, ensuring the quality and reliability of scientific research. Vagus nerve stimulation (VNS) showed that it can be deployed as an alternative treatment for patients suffering from drug-resistant depression and epilepsy. However, VNS is highly invasive and comes with great risks. The non-invasive transcutaneous VNS (tVNS) may induce this similar effect, by targeting the locus coeruleus-noradrenergic pathway (LC-NA). In the current study, we replicated the paper by Sharon et al. (2021), investigating the effect of tVNS on human pupil dilation. Throughout the experiment, the left ear of each participant was stimulated with the tVNS device, using short pulses of 3.4 seconds. Furthermore, pupillometry was deployed as a measure for pupil dilation. The outcome of this replication was in contrast with Sharon et al. (2021), as the results showed no significant difference between the tVNS and the sham condition. The final results might have been affected by the small sample size, the different adoption of materials, and an unequal ratio of males and females among participants. Future research should use a larger sample size, replicate more consistently and systematically, and adopt an equal ratio of gender. More research is necessary to establish reliable parameters for discoveries on the probable therapeutic effects of tVNS.Show less
This study investigated the relationship between Pyrrhonism and happiness, moderated by a present-fatalistic time perspective. Pyrrhonism is a philosophical tradition which can be regarded as an...Show moreThis study investigated the relationship between Pyrrhonism and happiness, moderated by a present-fatalistic time perspective. Pyrrhonism is a philosophical tradition which can be regarded as an art of living, with happiness as its ultimate goal. The Pyrrhonist recognises that for every outlook on life an equal amount of affirming and disconfirming arguments can be found and thus suspends his judgement, which leads to tranquillity. The Pyrrhonian trait, indicated by an investigative, considerate and open mind, was measured using the self-constructed Pyrrhonian Trait Scale (PTS). Data were collected using an online test battery, which in addition to the PTS also consisted of the Satisfaction with Life Scale and Zimbardo Time Perspective Inventory. An exploratory factor analysis was performed on the PTS to confirm the presence of underlying factors on which the scale was based. Subsequently, a regression analysis and moderation analysis were conducted using IBM SPSS. Although no significant relationships were found, Pyrrhonism was positively associated with happiness. This association was only positive in respondents scoring moderately on the present-fatalistic time perspective. Pyrrhonism might serve as a guide in daily life. Moreover, future studies could asses its effect in clinical settings.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Background: Research has identified psychological factors as important predictors of highly prevelant persistent somatic symptoms (PSS). However, this research is generally not based on primary...Show moreBackground: Research has identified psychological factors as important predictors of highly prevelant persistent somatic symptoms (PSS). However, this research is generally not based on primary care data and general practitioners (GPs) experience difficulties identifying PSS in their patients. Awareness of the psychological risk factors noted in readily accessible electronic medical records (EMRs) might aid GPs with earlier discovery and treatment. Aim: The objective was to examine the predictive value of psychological registrations in primary care for PSS onset. Method: We employed a retrospective longitudinal cohort design. EMR data of Dutch primary care patients were allocated into different subsamples according to registrations of irritable bowel syndrome (IBS), chronic fatigue syndrome (CFS), fibromyalgia (FM), and a combination of these registrations (COMBI) with age and sex-matched non-PSS cohorts. Candidate predictors were registered psychological symptoms, mental health referrals, and psycho-pharmaceuticals registered prior to PSS onset. The relevance of each candidate predictor was determined via L1 regularization in a logistic Lasso regression. The resulting prediction models’ performance was assessed via area under the curve (AUC). Results: The AUC indicated a fair classification performance for IBS (AUC IBS = .77), and good classification performances for CFS, FM, and COMBI (AUC CFS = .82, AUC FM = .88, and AUC COMBI= .87). The IBS-, CFS-, FM-, and COMBI-models, retained a total of 27, 12, 22, and 15 predictors, respectively. The strongest predictor per model was registration of sexual dysfunction for IBS (OR = 4.0), concentration disorder for CFS (OR = 2.4), neurasthenia for FM (OR = 3.0), and concentration disorder for COMBI (OR = 3.8). Neither of these predictors was unique to one specific model. Each final model retained mental health referrals, psycho-pharmaceuticals, and certain psychological symptom registrations as valuable predictors. Based on shared predictors IBS and FM had the closest models while IBS and CFS models were the most dissimilar. Discussion: These findings indicate that several psychological registrations are valuable predictors for onset of IBS, CFS, and/or FM. Therefore, GPs should consider the according predictors when screening for PSS. Future research could examine the comparatively low classification performce for IBS and psychological factors outside of primary care across PSS subtypes.Show less
Master thesis | Cultural Anthropology and Development Sociology (MSc)
open access
Indonesia is one of the countries vulnerable to the impact of climate change due to its geography. Climate change has threatened the agriculture industry and the country’s ability for food security...Show moreIndonesia is one of the countries vulnerable to the impact of climate change due to its geography. Climate change has threatened the agriculture industry and the country’s ability for food security which can be a severe problem in the future. However, there are problems with how the government of Indonesia is trying to manage the impact of climate change on agriculture, especially on rice paddy farming, due to the impacts of the past neo-liberal policy (the green revolution) and challenges within the political reformation after the downfall of the Soeharto regime. In this thesis, I am trying to explore the implications and the causes of agricultural and climate issues management problems in Indramayu, Indonesia, by utilizing Aryo Danusiri’s (2018) visual methods of menjaring (trawling) and berburu (hunting). In understanding the implications, I was using the trawling method where I argue that climate change and agricultural management problems in Indonesia are creating a precarious situation for the rice paddy farmers, in line with Anna Tsing’s (2015: 20) statement of precarity being the condition of our time. Lastly, I was using the hunting method where I found out that ‘sectoral ego’ problems within the government and aggressive neo-liberal politics as one of the major causes.Show less
Reorientation of attention is a fundamental part of human cognition. Spatial orientation is generally associated with dorsoparietal regions in the brain. Particularly, the posterior parietal cortex...Show moreReorientation of attention is a fundamental part of human cognition. Spatial orientation is generally associated with dorsoparietal regions in the brain. Particularly, the posterior parietal cortex, the lateral intraparietal cortex, and the right angular gyrus (AG) are assumed to mediate redirection of attention to behaviorally relevant stimuli. However, exact mechanisms and effect structures of reorienting to biologically significant stimuli have not been comprehensively identified. Time course and coordination in the dorsoparietal cortex remain unclear. Previous research has shown prioritized processing of emotional stimuli, particularly if threatening. Such affective processing is often associated with faster, subcortical activity. In the present study mediation by the right AG of reorienting to threat is examined. A spatial cueing paradigm was used and single pulse transcranial magnetic stimulation (TMS) was applied to the right AG at different stimulus onset synchronies (SOA) after target onset. Threat was introduced by means of differential fear conditioning of the targets stimulus. General linear mixed models with logit transform were used for analysis. TMS was predicted to interfere with reorienting (during invalid-cue trials) at an early SOA when threat is present. No such effects were observed. Rather, mediation by the right AG appeared to predominantly facilitate a correct response for contralateral targets. Further, TMS at 210 ms SOA improved performance for valid-cue conditions, independent of threat, suggesting that the right AG may act as inhibitory control. The discussed findings indicate a need for further investigation and suggested replication of more fundamental assumptions, such as direction of effects and lateralization of the AG.Show less
Trauma, cognitive flexibility, and empathy are widely studied constructs in psychology. However, inconsistent results are found regarding the aftermath of trauma. In the current study, it was...Show moreTrauma, cognitive flexibility, and empathy are widely studied constructs in psychology. However, inconsistent results are found regarding the aftermath of trauma. In the current study, it was expected that Syrian refugee children with higher severity of trauma symptoms scored significantly higher on cognitive flexibility and empathy tests than children with lower severity of trauma symptoms. To investigate these hypotheses, a quantitative cross-sectional study was conducted with a between-subjects design. The participants were asked to complete three questionnaires and two computer tasks to measure their cognitive flexibility, empathy, and trauma symptoms. Linear regression analyses showed that trauma was not a significant predictor of cognitive flexibility or empathy. If future studies could find this relationship in a larger sample, it possibly has implications for actively using cognitive flexibility and empathy as resilience factors during education for mental health professionals, therapeutic treatments of trauma, and in educational settings.Show less
Background. Stigmatization frequently occurs in individuals with a skin condition such as psoriasis, which can negatively influence their mental health and disease status. While stigma is known to...Show moreBackground. Stigmatization frequently occurs in individuals with a skin condition such as psoriasis, which can negatively influence their mental health and disease status. While stigma is known to be the leading cause of disability for these individuals, little is known about stigmatizing attitudes among the general population and its correlates. This study aimed to examine stigmatizing attitudes towards psoriasis among the Dutch population and investigated possible predictors. Methods. An online survey was administered to 124 participants, which were recruited based on convenience sampling. A 3 x 1 within-subject cross-sectional design was used, investigating the difference in stigmatizing attitudes towards the health conditions psoriasis and common cold (included due to COVID-19), and a healthy control condition. To describe the different conditions, vignettes were used. A one-way repeated measure Manova examined differences between the three conditions on stigmatizing attitudes (assessed by a social distance scale, a direct and indirect version of the impact of skin condition in daily life scale, stereotype endorsement scale, and emotion ratings). In addition, zero-order correlations and multiple regression analyses investigated possible predictors of stigmatizing attitudes towards psoriasis, including sociodemographic variables, familiarity and knowledge about psoriasis, indicators of the behavioral immune system and fear of corona. Results. Manova analysis displayed higher stigmatizing attitudes towards individuals with psoriasis as compared to the control group (p<.001). Besides, overall higher stigmatizing attitudes towards a common cold as compared to the psoriasis group were found. Higher stigmatizing attitudes towards psoriasis were correlated with lower knowledge, higher pathogen disgust, higher perceived infectability, male gender, and familiarity with psoriasis. No correlations were found regarding age, education, fear of corona, or gem aversion. Multiple regression displayed male gender, higher levels of pathogen disgust, and lower levels of knowledge about psoriasis to be predictors of stigmatizing attitudes (p<.05). Conclusion. Stigmatizing attitudes towards psoriasis is shown to be prevalent in Dutch society. As stigmatizing attitudes were shown to be related to reduced knowledge and male gender, future interventions might focus on these factors. Besides, different age groups and professions could be investigated in future studies. Further research is needed, as stigma towards psoriasis is rarely been investigated among the public.Show less
Posttraumatic Stress Disorder (PTSD) is a highly prevalent and debilitating disorder. The first line treatment for PTSD is prolonged exposure (PE) therapy. Inhibitory learning theory proposes...Show morePosttraumatic Stress Disorder (PTSD) is a highly prevalent and debilitating disorder. The first line treatment for PTSD is prolonged exposure (PE) therapy. Inhibitory learning theory proposes threat expectancy violation as a strategy to enhance effectiveness of PE. No standardized instrument for the assessment of threat expectancies is currently available. The aim of the current study was to assess the psychometric properties of the TREE, a novel instrument to assess threat expectancies. The reliability and factor structure of the TREE were assessed in a non-clinical sample of 158 trauma-exposed individuals. The TREE showed excellent reliability and was found to consist of four subscales: 1. Fear of dying/losing control, 2. Externalizing symptoms, 3. Negative evaluation, 4. Internalizing symptoms. The reliability of all subscales was good with an internal consistency ranging from .75 to .85. The TREE allows clinicians to tailor exposure sessions to the individual threat appraisal profile of their patients. Furthermore, by making threat expectancies explicit, it can aid in further understanding the mechanisms underlying PE. The factor structure of the TREE should be confirmed and its generalizability to the non-clinical and clinical population should be corroborated in future research.Show less
Background and aim: Although literature suggests that quality of life (QoL) in women with substance use disorders (SUDs) is lower than in men, it remains unknown whether this 1) applies to SUD...Show moreBackground and aim: Although literature suggests that quality of life (QoL) in women with substance use disorders (SUDs) is lower than in men, it remains unknown whether this 1) applies to SUD patients with psychiatric comorbidities in the Netherlands; and 2) whether there is a gender difference in QoL gain during treatment. This study therefore aimed to compare QoL (gain) between genders. Because research linked mood problems to worse QoL and substance usage in women, it was also the aim to compare genders in the association between (change in) mood problems and (change in) QoL. Methods: The longitudinal design involved data of day-patient treatments between 2018-2020. Sixty nine females and one hundred and thirty males with SUDs and comorbidities were assessed, using the EQ-5D-3L and the ICECAP-A. Analysis of variance and moderation analyses were performed with multiple imputation, controlling for treatment group. Results: At pretest, QoL in women was significantly lower when compared to men. There was no significant gender difference concerning gain in QoL, as well as regarding the association between mood problems and QoL at pretest and posttest. Conclusions: Women with SUDs and comorbidities experience lower QoL than men, a gender gap that is less profound in the normal population. Stigma and adverse life conditions arguably play a role. There is no evidence that men and women profit differently from treatment. In any case, mood problems, trauma experiences and meaningful activities could be considered more in future studies, as their association with QoL seems to be critical.Show less
Objectives: Some of the domains in which more experienced practitioners have been shown to outperform their less experienced colleagues relate to interpersonal skills, that can be measured by...Show moreObjectives: Some of the domains in which more experienced practitioners have been shown to outperform their less experienced colleagues relate to interpersonal skills, that can be measured by performance-based measure called Facilitative Interpersonal Skills (FIS). FIS has been identified as a strong predictor of treatment outcome, yet it is not known whether the FIS score is dependent on therapeutic experience. The present study tested the impact of clinical experience on FIS task performance by examining the influence of experience on FIS total score and the eight domains. Method: A total of 46 clinical psychology master’s students and 94 licensed cognitive-behavioural therapists participated in FIS assessment and provided information on their prior clinical experience. To test the hypotheses the multi-level growth model for repeated measures was employed. Results: Experienced therapists, on average, scored higher on FIS assessment than master’s students. The analyses of individual FIS domains revealed that the therapists performed significantly better on the 5 out of 8 FIS domains. Conclusions: Results were consistent with the hypothesis that the FIS assessment is dependent on one’s level of experience. The results imply that interpersonal skills can be modified through training or over the course of a therapeutic career. Conceptual and practical considerations of the findings are discussed.Show less
This paper explores the trajectory of amyloid accumulation onset in the brain relative to cognitive decline to potentially improve secondary prevention efforts of Alzheimer’s disease (AD). This was...Show moreThis paper explores the trajectory of amyloid accumulation onset in the brain relative to cognitive decline to potentially improve secondary prevention efforts of Alzheimer’s disease (AD). This was accomplished by attempting a replication of the study "Spatiotemporal distribution of β-amyloid in Alzheimer's disease is the result of heterogeneous carrying capacities" (Whittington et al., 2018) using data obtained from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. Results showed that Whittington’s model of the temporal evolution of the in vivo PET β-amyloid signal over time (i.e. using the four parameters: the tracer nonspecific binding (NS), the exponential uninhibited growth rate (r), the time of half-maximal β -amyloid concentration (T50) and the carrying capacity (K)), and the derived “estimated time since disease onset” could be used to model β-amyloid accumulation trajectory. Additionally, by studying the relationship between the trajectory of amyloid accumulation and cognitive decline, the results showed that amyloid accumulation in the brain does precede cognitive decline and can be modeled to predict cognitive deterioration. Thus, it was concluded that “estimated time since disease onset” does serve as a possible effective predictive diagnostic tool of cognitive impairments and AD pathology. Additionally, this study emphasizes the need for future research on the mechanisms by which amyloid accumulation influences cognitive impairments.Show less
As inertia lacks a comprehensive definition, this thesis aids the formulation of a singular yet widely applicable definition. This is accomplished by examining the feasibility of definitions...Show moreAs inertia lacks a comprehensive definition, this thesis aids the formulation of a singular yet widely applicable definition. This is accomplished by examining the feasibility of definitions obtained through the scientific literature (a top-down approach) and laypeople (a bottom-up approach). A single definition for inertia proves to be elusive due to inertia’s many different uses, interpretations, and overlap with other constructs. For this reason, several distinguishing features were identified to differentiate inertia. In addition, a dichotomy between inertia as a behaviour and tendency was proposed to reconcile contradictions within the literature. Nevertheless, a classical definition with clear boundaries proved to be problematic. Therefore, a bottom-up approach examined through a prototype analysis whether inertia may have a prototype structure. In this case, inertia is best explained through many distinct, yet overlapping concepts instead of a few boundary conditions. In Study 1, participants freely generated features of financial decision-making. In Study 2, the resultant features were adapted to financial inertia and were tested for their representativeness. These preliminary analyses indicated that inertia might indeed have a prototype structure as numerous features were considered central to inertia. While these inferences are somewhat tentative until inertia’s prototype structure is fully confirmed in subsequent tests, there are indications that the dichotomy following from the top-down approach may mirror patterns in the most centrally rated features from the bottom-up approach.Show less
