Research master thesis | Psychology (research) (MSc)
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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
Research master thesis | Psychology (research) (MSc)
closed access
Background: Theoretical models propose that parenting practices play a role in the development and maintenance of child depression. However, previous meta-analytic findings indicated that parenting...Show moreBackground: Theoretical models propose that parenting practices play a role in the development and maintenance of child depression. However, previous meta-analytic findings indicated that parenting accounted for only 5-11% of the variance in childhood depression, with varying effects for different types of parenting behaviors. Research Question: The current study aimed to investigate the association between observed negative/positive parenting behavior, childhood depression, and child gender, while controlling for the confounding effects of type of informant and assessment approach for childhood depression. Method: Two meta-analysis were conducted for the negative parenting – childhood depression and positive parenting – childhood depression association, while including moderating and confounding variables. The current study included thirty articles in total, with nineteen examining negative parenting behaviors and twenty-three examining positive parenting behaviors. Results: Observed negative parenting behavior was positively and observed positive parenting behavior was negatively related to childhood depression, with overall small effect sizes. Type of parenting behavior, child gender, and assessment approach for childhood depression did not moderate the associations. Type of informant for childhood depression explained some variance in the positive parenting – childhood depression association. Conclusions: Parenting interventions for childhood depression might aim to improve a broader range of parental behaviors. Future research is advised to compare actual to perceived parenting behaviors and investigate the direction of the parenting – childhood depression association, while adopting a multiple levels of analysis perspective. This could possibly contribute towards developing most effective personalized interventions for childhood depression, while lowering the high burden of depression.Show less
Research master thesis | Psychology (research) (MSc)
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Having an extra sex chromosome is known as sex chromosome trisomy (SCT). This may result in 47,XXY, 47,XXX, or 47,XYY. Previous research suggested that social attention to the eyes is reduced in ...Show moreHaving an extra sex chromosome is known as sex chromosome trisomy (SCT). This may result in 47,XXY, 47,XXX, or 47,XYY. Previous research suggested that social attention to the eyes is reduced in (young) adults with SCT and that individuals with SCT have more autistic characteristics compared to typically developing (TD) controls. It was unknown whether the group differences were also present in early childhood. The current study aimed to explore social attention, autistic traits, and their relation in three subgroups of children with SCT (47,XXY, 47,XXX, and 47,XYY; N = 70), aged 3 to 7 years, in comparison to TD peers (N = 62). Social attention to the eyes was measured using three eye-tracking video paradigms: A single-face condition, a multiple-face condition and a social interaction condition. Autistic traits were measured using the Social Responsiveness Scale-Second Edition. Results showed a difference in social attention between children with SCT and TD children during the social interaction condition. There was no difference in social attention between the SCT subgroups. The SCT group showed more autistic traits than the TD group and the 47,XXX subgroup had more autistic traits than the 47,XXY subgroup. There was a significant relation between social attention during the single-face condition and autistic traits in the 47,XYY subgroup only. Implications of these findings are discussed in relation to the importance of monitoring socio-cognitive challenges related to SCT in early childhood.Show less
Research master thesis | Psychology (research) (MSc)
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The optimal strategy in a semantic verbal fluency (SVF) task is to focus on one semantic subcategory at a time and adaptively switch from one subcategory to another. This task has therefore been...Show moreThe optimal strategy in a semantic verbal fluency (SVF) task is to focus on one semantic subcategory at a time and adaptively switch from one subcategory to another. This task has therefore been used as a measure of self-directed executive functioning. Previous studies have found that SVF performance improves through childhood and adolescence. This developmentalimprovement has been observed both in the total number of words produced during the task and in switching between subcategories. The present online study tested the hypothesis that the agerelated improvement in SVF performance is partly driven by an improved ability to select between competing word representations. The study included three age groups: 8–10-year-olds (n=26), 12–14-year-olds (n=17), and young adults (n=31). The semantic blocking effect in the blocked cycling naming task was used as a measure of selection abilities. Measures of vocabulary and general processing speed were included as control variables. Age-related differences in SVF performance were only partly replicated: there were signs of age-related differences in the total word count but not in switching. The semantic blocking effect was replicated across age groups. However, there were no signs of age-related differences in the magnitude of this effect, suggesting that word selection abilities did not differ between age groups. Moreover, the magnitude of the semantic blocking effect did not predict SVF performance. Thus, although further research is needed, the present study does not support the hypothesis that the age-related improvement in SVF would be driven by an improvement in selection abilities.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Using a wide variety of clinical questionnaires might hamper the communication between clinicians and researchers in Routine outcome monitoring (ROM). Linking test scores to T scores as a common...Show moreUsing a wide variety of clinical questionnaires might hamper the communication between clinicians and researchers in Routine outcome monitoring (ROM). Linking test scores to T scores as a common metric might be a solution. Item response theory (IRT) is the preferred way to estimate T-scores. However, required software and a large dataset is needed for that. In this thesis, two methods were used to arrive at a common metric for often used questionnaires and their subversions: the BSI, BSI-18, the DASS-42 and the DASS-21. As one method, we used an IRT approach to estimate theta-based T-scores, leading to crosswalk tables. For the second approach, conversion formulas were estimated for raw scores to calculated T-scores based on the best-fitting regression equation between the raw scores and the previously estimated theta-based T-scores. Crosswalk tables and conversion formulas are both alternative ways to link individual scores to a common metric. It was investigated if conversion formulas are valid by comparing calculated T-scores with theta-based T-scores. The agreement between calculated T-scores and theta-based T-scores were high for all questionnaires except the DASS-42. The agreement was also lower at the extreme ends of the questionnaires (T= < 50 and T= >75). All in all, conversion formulas seem to be a good alternative for estimating a common metric. Offering different options to calculate common metrics can help in improving the communication between professionals in the clinical field. Increased involvement and better communication in ROM is able to increase the quality of mental health care.Show less
Research master thesis | Psychology (research) (MSc)
closed access
This study aimed to investigate the effectiveness of a newly developed dynamic test for phonological and prosodic awareness in children with and without dyslexia. Additionally, the impact of...Show moreThis study aimed to investigate the effectiveness of a newly developed dynamic test for phonological and prosodic awareness in children with and without dyslexia. Additionally, the impact of reading self-concept was investigated. 30 children with dyslexia and 48 without dyslexia (Mage = 10.55) were included. The study consisted of two sessions: In the first session, all children completed a reading self-concept questionnaire. In the second session, the children were randomized into an experimental or control condition for a test-training-test design. Children in the experimental condition received a dynamic training between pre-test and post-test, the control condition did not. Results indicated that trained children had improved more on prosodic awareness than non-trained children. This effect was not found for phonemic awareness. Dyslexia diagnosis did not influence improvement. Furthermore, children with dyslexia had lower reading self-concept compared to children without dyslexia. However, reading self-concept was not related to improvement during a dynamic test, and dyslexia diagnosis did not moderate this relationship.Show less
Research master thesis | Psychology (research) (MSc)
open access
Identical sensory input may be perceived differently, based on expectations and goals. For example, object recognition is facilitated for expected or task-relevant objects. At the same time,...Show moreIdentical sensory input may be perceived differently, based on expectations and goals. For example, object recognition is facilitated for expected or task-relevant objects. At the same time, unexpected objects are found to elicit a stronger neural response. These effects can be explained by predictive coding accounts of visual processing, presenting perception as a process of minimizing the difference between predicted and observed sensory input. However, as expectation and task-relevance are often conflated, it is insufficiently clear how these factors influence sensory processing in conscious perception. The current study aimed to investigate the relative influence of expectation and task-relevance on behavioral and neural measures of perception. During two EEG sessions, participants performed a task in which they discriminated between masked face and house images while we independently manipulated expectation and task-relevance. We find that images were more often correctly recognized when they were expected or task-relevant. In addition, we used multivariate pattern analysis to show that a classifier trained on sensory representations of face and house stimuli is better able to distinguish between expected or task-relevant face and house images than between unexpected or task-irrelevant images. These results suggest that expectation and task-relevance have independent effects on sensory processing. Finally, our results show that cue-based manipulations may activate sensory templates even before stimulus onset. We therefore recommend that future studies manipulate expectation and task-relevance without the use of explicit cues.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Background: Information processing impairments are frequently observed in posttraumatic stress disorder (PTSD). Yet, the neurobiological underpinnings of these impairments are not well understood....Show moreBackground: Information processing impairments are frequently observed in posttraumatic stress disorder (PTSD). Yet, the neurobiological underpinnings of these impairments are not well understood. Mismatch negativity (MMN) is an event-related potential (ERP) that is thought to represent early sensory change detection. Previous electro-encephalography (EEG) studies on MMN in PTSD have revealed inconsistent results, with findings of both enhanced and reduced MMN amplitudes. Objective: We aimed to extend previous MMN findings to trauma-affected refugees, a PTSD population that often presents with complex, chronic, and severe forms of PTSD. Methods: We examined amplitudes and latencies of MMN in 25 refugees with PTSD and 20 healthy refugee controls matched on age, sex, and country of origin. We employed an MMN paradigm with three types of sound deviants: frequency, duration, and frequency-duration combined. Furthermore, associations between MMN amplitudes and clinical scores of PTSD and functioning were examined. Results: There were no significant differences in MMN amplitudes or latencies in PTSD versus control participants, following any of the deviants. Exploratory analyses revealed a significant sex-by-group interaction effect on MMN following the frequency-duration combined deviant, with enhanced MMN amplitudes in women with PTSD compared with controls. This pattern of findings was not found for the other deviants. Significant associations were found between MMN amplitudes and clinical scores in women only. Conclusion: Our findings point towards sex-differences in the underlying mechanisms of PTSD in refugees, highlighting the need of considering sex in future MMN studies.Show less
Research master thesis | Psychology (research) (MSc)
open access
Recent work has shown that we can achieve a better understanding of learning behavior by integrating reinforcement learning models with evidence accumulation models (RL-EAM). RL-EAM predict that as...Show moreRecent work has shown that we can achieve a better understanding of learning behavior by integrating reinforcement learning models with evidence accumulation models (RL-EAM). RL-EAM predict that as people learn they respond faster and more accurately. However, two recent experiments showed that when learning under speed pressure, people demonstrated a learning-related increase in accuracy, but not in response speed. We hypothesized that this might be caused by a proportion of responses resulting from a timing accumulation process that keeps track of time in parallel to the evidence accumulation process during a decision. We compared RL-EAM with and without the addition of time estimation on data from two independent experiments. We found no compelling evidence that the proposed mechanism of time estimation aid in decision-making in learning.Show less
Research master thesis | Psychology (research) (MSc)
open access
Evidence-based mental health programs have long conceptualized mental disorders as interactions between thoughts, feelings, behaviours and external factors. Idiographic network models are a...Show moreEvidence-based mental health programs have long conceptualized mental disorders as interactions between thoughts, feelings, behaviours and external factors. Idiographic network models are a relatively novel way of estimating such intra-individual psychological processes. These methods are not without limitations, and concerns have been raised about the stability and accuracy of estimated networks. The extend to which idiographic networks are stable, or vary over time, is unknown. We explored temporal network stability from three angles, exploring variation within people, across different stability metrics, and across people. We reanalysed daily symptom records of people with personality disorders. We fit graphical Vector Autoregressive models separately for the first and second 50 days of consecutive measurements. Contemporaneous but not temporal idiographic networks appeared to be relatively stable within people. The assessment of stability varied considerably across metrics applied. There was large variation in network stability of contemporaneous structures across people, which could not be explained by subject-specific variables. We illustrate the temporal changes in contemporaneous network structures of two participants with high and low network stability and discuss the most pressing questions to be considered by future research.Show less
Research master thesis | Psychology (research) (MSc)
open access
Eating disorders (EDs) are characterized by extreme symptom heterogeneity within diagnostic categories, which complicates treatment and inherently causes high relapse rates. The ability to predict...Show moreEating disorders (EDs) are characterized by extreme symptom heterogeneity within diagnostic categories, which complicates treatment and inherently causes high relapse rates. The ability to predict ED course in individuals would support clinicians in identifying early warning signals of relapse and to intervene accordingly. Traditional approaches have considered EDs as the shared origin of all symptoms which are reflective of a disorder, hindering prediction as it does not allow to unravel mechanisms of symptom progression. Network analysis provides new insights on EDs as it allows to model symptoms as networks of mutually causal relationships. However, most network analysis studies are limited as they only allow for conclusions on group-level at one single time point. By using time series data and intraindividual networks we can incorporate both individual and temporal information yielding insight in within-person variations over time. In this proof-of-concept study, we predicted ED severity using time series and intra-individual network features derived from ecological momentary assessment data in a transdiagnostic ED sample (n = 63). We explored whether time series and network features added to model performance on top of demographic and clinical features using machine learning and what features were most predictive of ED severity. Our findings show no convincing evidence that time series and network features improve predictive accuracy. Nonetheless, some time series and network features were identified as important, highlighting their potential clinical value. We consider our proposed combination of intra-individual networks and machine learning as a starting point towards personalized prediction of psychological outcomes.Show less
Research master thesis | Psychology (research) (MSc)
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Our current understanding of the neural signals entailing motor preparation is heavily based on tightly controlled laboratory experiments, which studies movement under prohibitively narrow...Show moreOur current understanding of the neural signals entailing motor preparation is heavily based on tightly controlled laboratory experiments, which studies movement under prohibitively narrow constraints. Despite a large body of literature on motor related cortical potentials (MRCPs), neural motor preparation in real life situations in still poorly understood: Insights from experimental studies often explore movement in low-dynamics contexts, meaning that most aspects of the movement are controlled by the experimental design rather than the participant. However, real life movements are more dynamic and display higher degrees of freedom, such as movement frequency, amplitude, speed, or spontaneity. In this study we address the temporal dynamics of touchscreen taps during unconstrained smartphone use and how they affect premotor EEG potentials. We used hierarchical linear modelling in order to determine how simple dynamics in inter-movement intervals can affect MRCPs. We found movement-preceding spatial and temporal clusters of EEG activity that are significantly affected by intervals to adjacent smartphone touches. Our results indicate that shorter intervals to previous touches result are related to a smaller amplitude of the readiness potential (RP) component, while shorter intervals to following touches are related to increased RP amplitude.Show less
Research master thesis | Psychology (research) (MSc)
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Introduction Frontotemporal dementia (FTD) is a young-onset neurodegenerative disorder with treatments still being in development. For trials testing such treatments, sensitive instruments to...Show moreIntroduction Frontotemporal dementia (FTD) is a young-onset neurodegenerative disorder with treatments still being in development. For trials testing such treatments, sensitive instruments to assess treatment effects are essential. This exploratory study aimed to identify such instruments by investigating gene-specific, presymptomatic cognitive decline and the underlying neural mechanisms of this decline. Methods We examined longitudinal cognitive decline using mixed effects models with natural cubic splines in six different domains for carriers of genetic mutations in GRN (n=46), MAPT (n=22), C9orf72 (n=29), and healthy controls (n=84). A voxel-based morphometry analysis was used to correlate cognitive decline to grey matter volume decline for the three mutation carrier groups. Results MAPT and C9orf72 mutation carriers showed a steeper decline on language (χ2(6) = 21.78, p = .001) and memory (χ2(6) = 18.42, p = .005) compared to GRN mutation carriers and controls. Decline in executive functions was associated with larger grey matter volume decline in the left superior and right middle frontal gyrus for C9orf72 mutation carriers and decline in language was associated with larger grey matter volume decline in the right anterior insula for MAPT mutation carriers. Discussion This study provides evidence of gene-specific cognitive decline in presymptomatic genetic mutation carriers of FTD. The findings highlight the importance of both neuropsychological and neuroimaging assessment which can be used as sensitive diagnostic biomarkers to identify and track disease progression in genetic FTD.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Minority activists benefit from the support of those advantaged in a system of inequality to alter the status quo. However, previous research suggests that members of advantaged groups often engage...Show moreMinority activists benefit from the support of those advantaged in a system of inequality to alter the status quo. However, previous research suggests that members of advantaged groups often engage in solidarity activism to bolster the moral image of their ingroup. We theorised that taking the moral high ground can be its own antecedent of collective action behaviour. In two studies, we investigated the role of group-based moral superiority in motivating collective action behaviour of solidarity activists in the Black Lives Matter movement. In Study 1 (n = 218) we examined the relationship between group-based moral superiority and both collective action intentions and activism persistence above and beyond traditional measures of collective action (i.e., SIMCA, Van Zomeren et al., 2008, 2012). In Study 2 (n = 209) we then manipulated group-based moral superiority experimentally to test whether higher levels of group-based moral superiority lead to increased collective action behaviour. Across both studies, we found support that group-based moral superiority plays an indirect role in increasing collective action intentions through stronger politicised group identification. The same indirect relationship was found for activism persistence in Study 1 but was not replicated in Study 2. We discuss implications of our findings for theory, future research directions, and practical aspects of collective action.Show less
Research master thesis | Psychology (research) (MSc)
open access
Attention plays a vital role in helping the brain adaptively disambiguate between relevant and irrelevant information in the environment. Lapses in attention can thus have important negative...Show moreAttention plays a vital role in helping the brain adaptively disambiguate between relevant and irrelevant information in the environment. Lapses in attention can thus have important negative consequences, varying from small mishaps to life-threatening mistakes and as such it is important to study their mechanisms. Neural entrainment appears to play an important role in attention and researchers have long tried to explore the relationship between the two. Unfortunately, a majority of studies on the topic relies heavily on animal and clinical studies, often using invasive measurement techniques. What is more, some of the non-invasive methods used (such as eye-tracking), sometimes offer contradicting results and lack methodological consensus. The current work is part of a larger study looking at the relationship between attentional lapses and neural entrainment using a multimodal oddball task. Here, we focused solely on eye tracking and set out to investigate whether lapses in attention correspond to changes in tonic pupil size and whether measures of attentional lapses suffer from time-on-task effects. Participants performed an oddball dual-modality task in which they were presented with two simultaneous streams of stimuli (visual and auditory) and had to attend and respond to either visual or auditory targets. We found that the number of false alarms reduced significantly over time and that pupil size showed a decreasing (albeit not significant) trend, while the number of hits did not appear to decrease as time passed. These findings seem to be in partial consensus with previous research on the topic. We also found a significant difference in pupil size between the two attending modalities (attend visual and attend auditory), suggesting that visual and auditory stimuli may influence attention (or at the very least pupil diameter) differently. There was however no difference in any of the behavioral measures based on the attended modality. Similarly, no effect of the pupil size was found for our behavioral measurements, suggesting that An investigation of the relationship between attentional lapses and pupil size 4 pupil size does not necessarily predict behavior. It must be noted however that while our results appear to contradict previous findings from the literature, our sample size is likely too small to draw any generalizable conclusions fromShow less
Research master thesis | Psychology (research) (MSc)
open access
Death by suicide a global health problem, often preceded with the experience of suicidal ideation. Both depression and anxiety increase the risk of experiencing suicidal ideation. However, the...Show moreDeath by suicide a global health problem, often preceded with the experience of suicidal ideation. Both depression and anxiety increase the risk of experiencing suicidal ideation. However, the specific relations between symptoms of depression and anxiety on the one hand, and suicidal ideation on the other, remain unexplored. Therefore, we investigated these relations both at the cross-sectional (N = 2981) and the temporal level (N = 2596), with a follow-up time of 2 years. We included data from the NESDA study and controlled for the covariates age and gender. To do so, we used unregularized network models, each consisting of 21 nodes. In each network, 10 nodes represented depression items, 10 nodes represented anxiety items, and one node represented suicidal ideation. Results showed that the relation between suicidal ideation and depression was stronger than the relation between suicidal ideation and anxiety. This held true at the cross-sectional and temporal level. Overall, depression and anxiety symptoms at baseline explained about 15% of suicidal ideation at the cross-sectional level, and up to 13% at the temporal level. However, these percentages are not directly comparable, because only for the temporal analyses did we control for previous suicidal ideation. Results should be replicated and further investigated in order to be able to draw firm conclusions.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Nocebo effects, i.e., unfavorable treatment outcomes that cannot be ascribed to active treatment components, play a key role in the persistence of physical symptoms. As conditioning is an important...Show moreNocebo effects, i.e., unfavorable treatment outcomes that cannot be ascribed to active treatment components, play a key role in the persistence of physical symptoms. As conditioning is an important factor in the induction of nocebo effects, counterconditioning may be a promising mechanism to reduce these effects. However, it is unknown whether conditioning and counterconditioning can effectively induce and reduce nocebo effects on a clinically-relevant pain modality, such as pressure pain. Furthermore, while various personality factors have been associated with susceptibility to the nocebo effect, little is known about a potential interplay between them. In the current study, we investigated in healthy participants whether nocebo effects on pressure pain can be induced, via open-label conditioning, and reduced via counterconditioning and whether counterconditioning is more effective than extinction. All procedures were combined with open-label verbal suggestions. Additionally, we investigated the roles of body vigilance, catastrophizing, and pessimistic tendencies in the induction and reduction of the nocebo effect. We found that conditioning could effectively induce a nocebo effect on pressure pain. Moreover, both counterconditioning and extinction were able to reduce the nocebo effect but counterconditioning was more effective. In addition, we did not find a significant relationship between the personality factors and the nocebo effect and its reduction. These findings indicate that counterconditioning with verbal suggestion is a promising strategy for reducing nocebo effects. Future research should investigate the generalizability of this method to a clinical population and should further examine the role of personality factors in nocebo effects.Show less
