This thesis summarizes a PhD research project, in which we successfully developed and tested a smartphone-based version of the AAT. We used the mobile AAT to show that approach-avoidance tendencies... Show moreThis thesis summarizes a PhD research project, in which we successfully developed and tested a smartphone-based version of the AAT. We used the mobile AAT to show that approach-avoidance tendencies can undergo substantial state-like changes. We further demonstrate how these changes can be systematically related to other state-variables and how important health-related outcomes such as overweight and obesity, can be explained by disruptions of these dynamics. Our findings have broad implications for approach-avoidance research and task-based research in general, as they reveal how smartphones can be used to get insights into the dynamic nature of task outcomes and how (disruptions of) these dynamics can have important real-life consequences. Show less
The current research examines joint collective action between advantaged and disadvantaged groups, from the perspective of the latter. We hypothesize that joint action poses a dilemma which lies in... Show moreThe current research examines joint collective action between advantaged and disadvantaged groups, from the perspective of the latter. We hypothesize that joint action poses a dilemma which lies in the tension between perceived instrumentality of joint action (i.e., ability to promote the disadvantaged’s goals) and perceived normalization (i.e., its tendency to blur power relations). We test this idea across three studies in the United States and Israel/Palestine. In Study 1 (n = 361) we manipulated perceptions of joint action from the perspective of a hypothetical character, and in Study 2 (n = 378) we presented participants with an article highlighting the risk and benefit of joint activism. Results showed that perceived instrumentality increases, whereas perceived normalization decreases joint action tendencies. In Study 3 (n = 240), we described a joint action event that taps into some of the themes that induce concerns about normalization. We found that normalization perceptions feed into perceptions of instrumentality, and this occurred mainly among high identifiers, for whom the dilemma is most salient. The implications of these findings for understanding the complexity of joint collective action from the perspective of the disadvantaged are discussed. Show less
This dissertation focused on the neural and behavioral mechanisms underlying adolescent learning and mental health in the context of peers and friends. The neuroimaging findings revealed that... Show moreThis dissertation focused on the neural and behavioral mechanisms underlying adolescent learning and mental health in the context of peers and friends. The neuroimaging findings revealed that reward processing for self and peers rely on common reward-related brain regions, whereas a social brain region (TPJ) showed social specificity to observed outcomes for unfamiliar peers compared to friends. Moreover, typically developing adolescents and adolescents with ADHD show neural sensitivity in reward and salience brain regions towards rewards for themselves, friends and peers compared to losses. There were no group differences in neural processing of (vicarious) outcomes between adolescents with and without ADHD, yet a symptom-level approach showed more neural sensitivity for own compared to friends’ losses in individuals with more inattention symptoms. The behavioral findings indicated that adolescents’ learning performance benefitted from observing the choices and outcomes of peers irrespective of the relationship with this peer. The results did not show effects of friendship (quality) and social status on observational and academic learning, but there was a protective effect of friendship quality on internalizing problems. Taken together, these findings highlight adolescence as a period of observational learning opportunities from different types of peers. Adolescence can also serve as a window of opportunity to improve mental health by fostering high-quality friendships. Show less
Schulze, A.; Hughes, N.; Lis, S.; Krause, A.D. 2024
Two types of financial incentives can help improve healthy lifestyles: carrots (a reward where one can gain something) and sticks (a deposit contract where one can lose something). In a deposit... Show moreTwo types of financial incentives can help improve healthy lifestyles: carrots (a reward where one can gain something) and sticks (a deposit contract where one can lose something). In a deposit contract, participants deposit own money and can lose or earn it back depending on lifestyle changes. We studied the potential of deposit contracts to stimulate a healthy lifestyle.A smartphone app was developed together with the Swiss university ETH Zurich to conduct experimental research into the effects of deposit contracts. In addition, we collaborated with the American company WayBetter to observe the effects of commercially available deposit contracts. Finally, the opinion of people with cardiovascular disease and healthcare professionals regarding financial incentives and deposit contracts for lifestyle change was investigated.The results show that deposit contracts can have strong effects on exercise behavior (daily step counts) in the short term. The results also show that voluntary participation in deposit contracts is limited, but can be increased by doubling the amount deposited and by allowing participants to determine the amount themselves. Finally, healthcare providers think it is a good idea to use financial incentives, but people with cardiovascular disease themselves are skeptical about the use of deposit contracts. Show less
Hoeber C.M., Kullberg M.-L.J., Oprel D.A.C., Schoorl M., Van Minnen A., Antypa N., Mouthaan J., De Kleine R.A., Van der Does A.J.W. 2024
BackgroundThe heterogeneous nature of cognitive impairment in people with multiple sclerosis (PwMS) hampers understanding of the underlying mechanisms and developing patient-tailored interventions.... Show moreBackgroundThe heterogeneous nature of cognitive impairment in people with multiple sclerosis (PwMS) hampers understanding of the underlying mechanisms and developing patient-tailored interventions. We aim to identify and classify cognitive profiles in PwMS, comparing these to cognitive status (preserved versus impaired).MethodsWe included 1213 PwMS (72% female, age 45.4 ± 10.7 years, 83% relapsing–remitting MS). Cognitive test scores were converted to Z-scores compared to healthy controls for the functions: attention, inhibition, information processing speed (IPS), verbal fluency and verbal/visuospatial memory. Concerning cognitive status, impaired cognition (CI) was defined as performing at Z ≤ − 1.5 SD on ≥ 2 functions. Cognitive profiles were constructed using latent profile analysis on all cognitive functions. Cognitive profiles or status was classified using gradient boosting decision trees, providing the importance of each feature (demographics, clinical, cognitive and psychological functioning) for the overall classification.ResultsSix profiles were identified, showing variations in overall performance and specific deficits (attention, inhibition, IPS, verbal fluency, verbal memory and visuospatial memory). Across the profiles, IPS was the most impaired function (%CI most preserved profile, Profile 1 = 22.4%; %CI most impaired profile, Profile 6 = 76.6%). Cognitive impairment varied from 11.8% in Profile 1 to 95.3% in Profile 6. Of all cognitive functions, visuospatial memory was most important in classifying profiles and IPS the least (area under the curve (AUC) = 0.910). For cognitive status, IPS was the most important classifier (AUC = 0.997).ConclusionsThis study demonstrated that cognitive heterogeneity in MS reflects a continuum of cognitive severity, distinguishable by distinct cognitive profiles, primarily explained by variations in visuospatial memory functioning. Show less
Pratiwi, B.C.; Dusseldorp, E.M.L.; Rooij, M.J. de 2024
ObjectivesTo study the frequency of isolated (i.e., single-domain) cognitive impairments, domain specific MRI correlates, and its longitudinal development in people with multiple sclerosis (PwMS)... Show moreObjectivesTo study the frequency of isolated (i.e., single-domain) cognitive impairments, domain specific MRI correlates, and its longitudinal development in people with multiple sclerosis (PwMS).Methods348 PwMS (mean age 48 ± 11 years, 67% female, 244RR/52SP/38PP) underwent neuropsychological testing (extended BRB-N) at baseline and at five-year follow-up. At baseline, structural MRI was acquired. Isolated cognitive impairment was defined as a Z-score of at least 1.5 SD below normative data in one domain only (processing speed, memory, executive functioning/working memory, and attention). Multi-domain cognitive impairment was defined as being affected in ≥ 2 domains, and cognitively preserved otherwise. For PwMS with isolated cognitive impairment, MRI correlates were explored using linear regression. Development of isolated cognitive impairment over time was evaluated based on reliable change index.ResultsAt baseline, 108 (31%) PwMS displayed isolated cognitive impairment, 148 (43%) PwMS displayed multi-domain cognitive impairment. Most PwMS with isolated cognitive impairment were impaired on executive functioning/working memory (EF/WM; N = 37), followed by processing speed (IPS; N = 25), memory (N = 23), and attention (N = 23). Isolated IPS impairment was explained by a model of cortical volume and fractional anisotropy (adj. R2 = 0.539, p < 0.001); memory by a model with cortical volume and hippocampal volume (adj. R2 = 0.493, p = 0.002); EF/WM and attention were not associated with any MRI measure. At follow-up, cognitive decline was present in 11/16 (69%) of PwMS with isolated IPS impairment at baseline. This percentage varied between 18 and 31% of PwMS with isolated cognitive impairment in domains other than IPS at baseline.ConclusionIsolated cognitive impairment is frequently present in PwMS and can serve as a proxy for further decline, particularly when it concerns processing speed. Cortical and deep grey matter atrophy seem to play a pivotal role in isolated cognitive impairment. Timely detection and patient-tailored intervention, predominantly for IPS, may help to postpone further cognitive decline. Show less
