In de huidige studie hebben we onderzoek gedaan naar de invloed van Intolerantie voor Onzekerheid (IU; nervositeit voor het onbekende) op processen zoals (1) zekerheid in het geven van een antwoord...Show moreIn de huidige studie hebben we onderzoek gedaan naar de invloed van Intolerantie voor Onzekerheid (IU; nervositeit voor het onbekende) op processen zoals (1) zekerheid in het geven van een antwoord en (2) reactietijd. Met kennis over mechanismen van IU kunnen we symptomen begrijpen en dagelijkse negatieve gevolgen verminderen. Gedurende het experiment kregen 54 gezonde participanten (37 vrouwen, 17 mannen) tussen de 18-40 jaar neutrale en negatieve afbeeldingen met bijhorende beschrijvingen te zien op twee verschillende dagen met 24 uur ertussen. Specifiek is gekeken naar dag twee, waarbij de participanten bij 75 neutrale en 75 negatieve afbeeldingen moesten aangeven of ze de afbeeldingen hadden gezien op de dag ervoor (oud) of niet (nieuw). Ze gaven aan hoe zeker ze waren over hun antwoord (betrouwbaarheidsbeoordeling; VAS 1-100; oud-nieuw). De reactietijd (ms) van deze respons werd voor beide condities gemeten. Daarna vulden participanten de Intolerance for Uncertainty Scale (IUS) in, bestaande uit 27 stellingen waarbij ze aangaven in welke mate de stelling hen typeert. De data zijn geanalyseerd middels niet-parametrische Friedmantoetsen, RMANCOVA en twee regressieanalyses met verschilscores. Daaruit kwamen de volgende bevindingen. Participanten met meer IU vertoonden minder spreiding in zekerheid van hun antwoord en waren gemiddeld langzamer in beide condities. Los van IU, vertoonden participanten meer spreiding in antwoordzekerheid en waren ze gemiddeld langzamer bij de negatieve dan bij de neutrale afbeeldingen. We concluderen dat IU effect heeft op de antwoordzekerheid en op de reactietijd. Of de getoonde afbeeldingen neutraal of negatief zijn blijkt hierbij niet van invloed.Show less
Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation technique showing promise in stroke rehabilitation, with evidence indicating significant enhancement in motor function of...Show moreTranscranial magnetic stimulation (TMS) is a noninvasive neuromodulation technique showing promise in stroke rehabilitation, with evidence indicating significant enhancement in motor function of the contralateral limb following treatment. While TMS appears promising for stroke rehabilitation, there is variability in the level of improvement individuals exhibit. This variability may be attributed to oscillatory neurophysiology, which refers to the rhythmic electrical activity of the brain. Therefore, this study investigated phase-dependent changes in cortical excitability after TMS among stroke patients in affected and unaffected hemispheres. We investigated motor-evoked and TMS-evoked potentials at four phases of the ongoing motor cortical mu rhythm (trough, peak, rising, falling) in both hemispheres (affected, unaffected). Participants comprised N=11 chronic subcortical stroke patients (6 female, mean ± std age: 58 y ± 11.4) with affected lateralized upper-limb impairment. Four blocks of 150 TMS pulses were applied on each hemisphere, targeting the primary motor hotspot of the first dorsal interosseus muscle of the contralateral hand. Participants watched nature videos during stimulation to maintain consistent attention levels. Cortical excitability was assessed by analyzing motor-evoked potentials (MEP) and TMS-evoked potentials (TEP). Results showed that motor responses (measured through MEP amplitudes) were significantly larger at the trough and rising phase compared to the peak phase. No significant differences were observed between the affected and unaffected hemispheres. TEP components, the brain signals in response to TMS, did not exhibit significant phase-dependent changes. While our findings showed a nonsignificant effect of stroke severity, exploratory correlation analyses presented a positive association between higher remaining movement function and enhanced phase-dependent responses to TMS. The findings build upon previous research indicating phase-dependent changes in cortical excitability for MEPs but not for TEPs. The larger MEP amplitudes during trough and rising phases suggest that TMS can be more effective at specific points of cortical activity. Further exploration is needed to assess the efficacy of phase-specific TMS interventions in clinical settings, potentially through larger-scale clinical trials with longitudinal designs and comparative effectiveness studies, aiming to evaluate functional outcomes and determine their impact on motor recovery.Show less
Background: Individuals with psychotic disorders (PD) often experience cognitive challenges, particularly in executive functioning (EF), crucial for daily functioning. Sleep disruptions, notably...Show moreBackground: Individuals with psychotic disorders (PD) often experience cognitive challenges, particularly in executive functioning (EF), crucial for daily functioning. Sleep disruptions, notably insomnia, are prevalent in PD, worsening symptoms and affecting overall well-being and treatment outcomes. Moreover, individuals with PD frequently engage in cannabis use, which can further impact EF. Gender differences may also play a role in how cannabis affects EF, though findings are varied. This study aims to deepen our understanding of the interplay between insomnia, EF, and cannabis use in PD individuals, while considering gender influences. We hypothesize that higher insomnia rates correlate with poorer EF in PD, with cannabis mediating this relationship. Additionally, we expect gender disparities to influence how cannabis affects EF. This study sheds light on critical factors affecting cognitive function in PD, aiding in tailored intervention strategies. Method: Data were collected from a randomly selected sample of patients (N=262) undergoing treatment at a mental health care clinic in the South-western part of the Netherlands at time of inclusion. Participants, aged between 18 and 65 at inclusion, had a primary diagnosis of a psychotic disorder. The current study utilized data from the Lichamelijke Klachten Vragenlijst (LKV), the Behavior Rating Inventory of Executive Function for Adults (BRIEF-A), and the Measurements in Addictions for Triage and Evaluation (MATE). Results: Significant correlations indicated a moderate positive association between insomnia and EF problems. However, mediation analysis did not support cannabis use as a mediator between insomnia and EF. Gender differences were explored through residual variances analysis, suggesting potential unaccounted factors impacting variability. Model fit indices revealed areas for improvement in explaining variance, warranting further examination and potential adjustments to refine the overall model fit. Conclusion: Higher rates of insomnia were related to higher rates of EF problems. There is no evidence for a mediating effect of cannabis use in this relationship. Gender differences did not seem to play a significant role in the effect of cannabis on EF. Future research should incorporate performance-based tasks alongside self-report measures to improve measurement precision. Future treatments could potentially benefit from incorporating interventions that address insomnia, as this may lead to potential enhancements in executive functioning.Show less
Pain, which substantially impacts one’s quality of life, is affected by various factors, including outcome expectancies. Although the effect of outcome expectancies has been studied extensively on...Show morePain, which substantially impacts one’s quality of life, is affected by various factors, including outcome expectancies. Although the effect of outcome expectancies has been studied extensively on pain perception, their impact on pain tolerance -defined as the ability to withstand a maximum pain intensity stimulus before seeking relief- remains mostly unknown. Furthermore, underlying mechanisms, that may be at play are not fully understood. This study aims to examine the role of induced outcome expectancies for pain tolerance, and the moderating role of optimism. It was hypothesized that the participants of the high outcome expectancy condition who received verbal suggestions about the expected outcome would exhibit higher pain tolerance than those in the neutral condition group, who did not receive any verbal suggestions. Additionally, optimism, comprised of positive outcome expectancies for the future, was hypothesized to moderate the relationship between outcome expectancies and pain tolerance meaning that outcome expectancies would decrease one’s sensitivity to pain more when optimism is high. The study’s factorial 2x2 between-subjects design involved randomizing healthy adults into a neutral control and high outcome expectancy condition group. Outcome expectancies were manipulated through verbal suggestions and assessed using a visual analog scale about the expected intensity of the upcoming stimulus. A Cold Pressor Test was used to assess pain tolerance, and dispositional optimism was measured by the Life Orientation Test-Revised. The analysis revealed no significant difference in expected intensity ratings between the two groups, suggesting a need for further improvement of the effectiveness of verbal suggestions. Similarly, no significant difference was observed in pain tolerance between the two groups and optimism did not demonstrate a moderating effect on the relationship between induced outcome expectancies and pain tolerance. Future research may further explore cognitive and psychological mechanisms while taking into account personal traits that may be responsible for the association between outcome expectancies and pain perception and tolerance.Show less
Disgust, rooted in human evolutionary history, serves as a vital defense mechanism against pathogens, manifesting in varied behaviors. This paper explores the intricate relationship between disgust...Show moreDisgust, rooted in human evolutionary history, serves as a vital defense mechanism against pathogens, manifesting in varied behaviors. This paper explores the intricate relationship between disgust and visual attention, employing the eye-tracking method. Drawing insights from primate studies, habituation, and human facial expressions, the research aims to address three key questions: Does gaze aversion occur in humans when exposed to disgusting stimuli, extending avoidance behavior into the visual domain? Do individuals exhibit prolonged attention to facial area, indicating a social imperative to assess the risk of pathogen contamination? How does gaze aversion change with repeated exposure to disgust-inducing stimuli? The study employs three conditions, including scenes of feces ingestion in the test condition, to assess total looking time. Results reveal significant gaze aversion towards feces as compared to control conditions, supporting the hypothesis of avoidance behavior. Participants displayed prolonged attention to faces during non-disgusting conditions, challenging assumptions about social necessity for risk assessment. Repeated exposure across trials to disgust-inducing stimuli did not significantly alter gaze behavior, highlighting the nuanced nature of responses to aversive stimuli. Discussion of the findings and implications are also addressed.Show less
Adolescence is a period marked by the pursuit of autonomy and asserting independence from parents, yet adolescents with mild-to-borderline intellectual disability (MBID) often rely more heavily on...Show moreAdolescence is a period marked by the pursuit of autonomy and asserting independence from parents, yet adolescents with mild-to-borderline intellectual disability (MBID) often rely more heavily on parental support compared to typically developing adolescents. This study examined parental involvement within a new cognitive behavioral therapy (CBT) approach where peers assist adolescents with MBID in confronting their fears. The study employed a stakeholder-driven approach, conducting focus groups and interviews to gather insights from various stakeholders: adolescents with MBID (n=17), parents of adolescents with MBID (n=8), and therapists (n=15). We examined how long participants discussed the topic parental involvement, how many words they dedicated to it, and whether they generally expressed the importance of parental involvement. Additionally, qualitative analyses are conducted on the opinions of the stakeholder groups regarding how they think that parents should be involved in therapy. Results indicated a prioritization of parental involvement by therapists and parents over adolescents with MBID. Therapists and parents utilized a greater number of words pertaining to parental involvement, dedicated more time to discussing parental involvement, and explicitly articulated its importance. Parents expressed a strong need for support and involvement throughout the therapy process, while therapists unanimously agree that parents should be actively involved in treatment. Adolescents, on the other hand, believed that parents should only be involved when necessary. Implications of the study suggest scheduling parental appointments before and during therapy, offering psychoeducation, support and facilitating meetings with other parents of adolescents with MBID. Also involving parents in therapy through video recordings and progress reports are recommended strategies. Importantly, soliciting the opinions and approval of adolescents regarding parental involvement is crucial, and the benefits of parental involvement should be clearly communicated.Show less
If employees are not able to deal effectively with their emotions, negative consequences may occur such as absenteeism, turnover, and poorer physical and mental health. Therefore this study aimed...Show moreIf employees are not able to deal effectively with their emotions, negative consequences may occur such as absenteeism, turnover, and poorer physical and mental health. Therefore this study aimed to investigate if exercise fosters emotion regulation. It was hypothesized that 1) exercise would lead to less negative emotions; 2) this relationship is mediated by adaptive emotion regulation strategies, and 3) this effect would be greater for individuals high versus low in sensory processing sensitivity. To investigate this, an experimental, between-subjects design was used. A total of 134 students were recruited from Dutch universities, who were randomly assigned to one of three conditions: exercise, active control (making a puzzle), or passive control (rest). During the experiment, all participants filled out a questionnaire measuring background variables, negative state emotions, and trait sensory processing sensitivity. After this, participants underwent a negative emotion induction task to elicit negative emotions and create a need to regulate emotions. They then spent thirty minutes on a cycle ergometer, doing a puzzle, or resting in a chair, after which adaptive emotion regulation strategies and negative emotions were measured. A mixed ANCOVA was conducted to test whether participants in the exercise condition experienced less negative emotions after cycling for thirty minutes than the participants in the control conditions, which was not supported by the data. The SPSS extension ,,PROCESS” was used to test the second (model 4) and third (model 7) hypothesis. Support was found for the expectation that participants in the exercise condition make more use of adaptive emotion regulation strategies after cycling for thirty minutes, and therefore experience less negative emotions than the participants in the puzzle or rest condition (significant full mediation effect). Lastly, the hypothesis that the effect of exercise on negative emotions via emotion regulation would be greater for those scoring higher on sensory processing sensitivity than for those scoring lower on this trait, was not supported. These findings further our knowledge on the interdependence of these variables, since inconsistencies found in the literature may be explained by the indirect effect found in this study. The role of adaptive emotion regulation may be key to understanding the underlying mechanisms of how exercise influences emotions. This could potentially impact the development of creating (workplace) interventions, where combining an exercise intervention with increasing the knowledge of the employees about adaptive emotion regulation strategies might be most effective. However, more research in this area is needed to test how generalizable this effect is, since there is reason to believe gender differences and natural preferences (versus lab imposed conditions) may influence these findings.Show less
In recent years, a lack of reproducibility in science has come to light. One of the causes of this lack of reproducibility is the use of questionable research practices (QRPs). P-hacking is one of...Show moreIn recent years, a lack of reproducibility in science has come to light. One of the causes of this lack of reproducibility is the use of questionable research practices (QRPs). P-hacking is one of these QRPs and consists of making impromptu data analytic choices, resulting in a biased significant p-value. The practice of blind analysis could be a viable option to tackle p-hacking. This thesis introduces a new categorization of blind analysis-methods: label blinding, noise blinding and coefficient blinding. Each of these categories has its own implications when it comes to the data analysis. Label blinding allows a researcher to check assumptions with the blinded data, but does not hide the actual p-values. Noise blinding prevents a researcher from checking assumptions with the blinded data, but hides the actual p¬-values. Coefficient blinding allows a researcher to check assumptions and hides the actual p-values, but requires a researcher to specify the model they are going to fit beforehand. Three case studies with simulated data illustrate what the plots and tests used for assumption checks look like for a method from each blind analysis category, as well as what the test statistics might look like. When using a label blinding method while conducting a two-way ANOVA, we are able to check the assumptions of a two-way ANOVA, but our results are not hidden, leaving an opening for p-hacking. When using a noise blinding method while conducting a two sample t-test, we are unable to check the assumptions of a two sample t-test, but our test results are hidden. When using a coefficient blinding method while conducting a linear regression analysis, we are able to check the assumptions of a linear regression and our test results are hidden. Not every blind analysis method is applicable to every dataset or data analysis. More research is needed to explore what blind analysis methods are applicable to which tests. Additionally, guidelines for the practical implementation of blind analysis should be specified.Show less
Objective. To determine the effectiveness of a rehabilitation program including physical exercise, in improving cognition, participation, and coping in patients with a subarachnoid hemorrhage (SAH)...Show moreObjective. To determine the effectiveness of a rehabilitation program including physical exercise, in improving cognition, participation, and coping in patients with a subarachnoid hemorrhage (SAH). Secondary, it was aimed to identify the role of clinical characteristics in the effectiveness of the rehabilitation program. Methods. A longitudinal pilot intervention study was performed, with measurements before the start (T0), after three months (T1), and after six months (T2). Cognition was measured with the Montreal Cognitive Assessment, participation with the Impact on Participation and Autonomy questionnaire, and coping with the Utrecht Proactive Coping Competence Scale. Generalized Estimating Equation analyses were performed. Results. A total of 19 patients with SAH participated; 13 in the intervention group and 6 in the control group. For the intervention group, cognition improved between T0 and T2 and between T1 and T2. Participation declined between T0 and T1, but improved between T1 and T2. Proactive coping declined between T0 and T2 and between T1 and T2. Cognition of the control group did not change, but participation improved between T0 and T1 and proactive coping declined between T0 and T1. There was no significant difference between the control and intervention groups in improvements in cognition between T0 and T1 (p = 0.090). However, there was a significant difference between the control and intervention groups in changes in participation between T0 and T1 (p = 0.001) and in changes in coping between T0 and T1 (p < 0.001). The location of SAH played a role in the differences in participation, but not in cognition and coping. For treatment type and time since SAH, no significant effects were found. Conclusion. There was no effect of the rehabilitation program on cognition. The control group had a better participation level after three months and the intervention group worsened. The intervention group had a stable coping style after three months, whereas the control group declined in the use of proactive coping. Only the characteristic location of the aneurysm played a role in the participation level after three months, but not in cognition or coping. The other characteristics did not play a role in the changes. This study indicates that some long-term complaints can improve after the rehabilitation program, but more research is needed.Show less
The lack of contact between a debtor and creditor has been identified as a big problem in overcoming financial stress and debt. This study aimed to investigate whether inducing control results in...Show moreThe lack of contact between a debtor and creditor has been identified as a big problem in overcoming financial stress and debt. This study aimed to investigate whether inducing control results in greater willingness to contact creditors. Furthermore, financial self-efficacy was investigated as a moderator of this relationship. A total of 134 participants were assigned to either an induced control group or a baseline group. The participants were asked to recall a negative financial experience and were then presented with a fictional letter from an imaginary creditor, urging them to contact the creditor as soon as possible. The creditor letter was left unchanged from a standard creditor letter in the baseline group, while in the control group, the letter offered two possibilities to help repay outstanding debt. After reading the letter, participants were asked if they would be willing to contact the creditor. The study found that there was a significant difference in the participants' willingness to contact creditors. However, financial self-efficacy was not found to be a significant moderator. The present study provides additional support to previous findings that increasing perceived control led to a higher willingness to contact in the context of financial hardship.Show less
Research master thesis | Psychology (research) (MSc)
under embargo until 2026-01-31
2026-01-31T00:00:00Z
Language control in bilingual speakers involves effectively switching between languages, inhibiting the non-intended language, and continuously monitoring speech errors. It has been a matter of...Show moreLanguage control in bilingual speakers involves effectively switching between languages, inhibiting the non-intended language, and continuously monitoring speech errors. It has been a matter of controversy concerning whether language control operates in a comparable manner to cognitive control processes in non-linguistic domains (domain-general) or if it is exclusive to language processing (domain-specific). Midfrontal theta oscillations have been considered as an index for increased cognitive control, so examining whether a similar midfrontal theta effect is likewise evident in bilingual language will bring new insights to the ongoing debate. This study aimed to explore midfrontal theta oscillations in bilingual control with a specific focus on three fundamental control processes: language switching, inhibitory control, and speech monitoring. We reanalysed the EEG data obtained from two previous language switching studies where Dutch-English bilinguals named pictures based on colour cues. Theta power increase was observed during language switching, specifically in switch trials compared to repeat trials, and this effect was observed in the midfrontal region. Similarly, enhanced midfrontal theta power was observed during error monitoring, specifically when participants failed to select the intended language at a switch, compared to correct responses. However, no midfrontal theta effect was found during inhibitory control, reflected by a missing modulation in switch trials following a short run (i.e., a short sequence of same-language repeat trials) compared to a long run (i.e., a long sequence of same-language repeat trials). These findings largely support the involvement of domain-general cognitive control mechanisms in language control, particularly in language switching and speech monitoring, whereas inhibitory control remains unclear.Show less
Experiencing financial hardship has many detrimental effects on mental health and often leads to avoidance coping, which only exacerbates the financial difficulties. As educational programs have...Show moreExperiencing financial hardship has many detrimental effects on mental health and often leads to avoidance coping, which only exacerbates the financial difficulties. As educational programs have not effectively addressed avoidance coping, this study examines the effectivity of a self-compassion intervention on avoidance coping through reducing financial shame and financial stigma. Furthermore, we explored the effects of the intervention on problem-focused coping, emotion-focused coping and financial stress. We surveyed N = 199 U.K. participants using the participant recruitment website Prolific. We performed a randomized, controlled two-group experiment where the effect of a self-compassion intervention on coping-styles was tested against no intervention. Results showed no significant effect of the self-compassion intervention, neither on avoidance coping nor on other forms of coping and financial stress. However, financial shame and financial stigma positively correlated with avoidance coping. Future research could investigate effective interventions addressing shame and stigma to reduce avoidant coping when experiencing financial hardships. Keywords: self-compassion, coping-styles, financial hardship, shame, stigma, avoidance-coping.Show less
Depression is a common, debilitating mental disorder. Due to its frequency and negative effects, there is a strong need for the development of efficient treatments. Especially since a large...Show moreDepression is a common, debilitating mental disorder. Due to its frequency and negative effects, there is a strong need for the development of efficient treatments. Especially since a large percentage of people is resistant to commonly prescribed antidepressant interventions. Rumination is an important symptom and predictor of depression, and it has been linked to dysfunctional default mode network (DMN) connectivity in depression. A better understanding of the relationship between the DMN and rumination may help us understand depression better, which may support the development of new interventions. This study focuses on rumination and its effects on the DMN during a working memory (WM) task in healthy participants. This was tested by inducing rumination in participants before the WM task, where DMN and DMN subsystem connectivity were compared to participants who did not receive rumination induction. Results showed that inducing rumination during tasks requiring external focus does not increase functional connectivity of the DMN. Both the overall DMN connectivity and subsystem connectivity did not show any significant differences between groups. Furthermore, time-related changes in DMN connectivity were explored, but results indicated no significant changes either. Studies with depression showed that DMN connectivity is increased during WM tasks which was linked to rumination. But in this study with healthy participants DMN connectivity was suppressed during the WM task, even after inducing rumination. Therefore, these findings suggest that inducing rumination does not lead to insufficient DMN suppression in healthy participants, and that insufficient depression may be exclusive to depression.Show less
