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
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
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
This thesis generated insights into the neural and affective signatures of connectedness between parents and adolescents and between people in general, which is operationalized by responses to eye... Show moreThis thesis generated insights into the neural and affective signatures of connectedness between parents and adolescents and between people in general, which is operationalized by responses to eye contact and empathy. Overall, our findings show that during adolescence, parents are still highly attuned to their child at the neural and affective level. In addition, adolescents report to feel more connected with their parents than with unknown others, although this was not directly reflected in stronger neural responses. Another interesting finding is that making eye contact for a prolonged period generally enhanced the socio-emotional connection between people, both between parents and adolescents and with unknown others. For individuals with a history of CEM and depressed adolescents eye contact is less socially rewarding, however, and does not seem to foster a stronger connectedness with others. Studying the psychobiological underpinnings of affiliative bonding, including the parent-adolescent bond, brings us a step closer to unraveling how such bonds are established and maintained during adolescence. And even more important: Once we know how these bonds are established, we might be better able to modify and repair these bonds in situations in which they for some reason got disrupted. Show less
Despite decades of research from psychology, anthropology, biology and economics, how social preferences arise and vary across contexts remains an open question. In three empirical chapters, this... Show moreDespite decades of research from psychology, anthropology, biology and economics, how social preferences arise and vary across contexts remains an open question. In three empirical chapters, this dissertation addresses this gap using a variety of economic games and neuroimaging techniques that allow for a tractable modeling of cooperation and competition. Overall, findings suggest that while social preferences are linked to neural structure, they can also adapt to environmental factors as well as beliefs about interaction partners. This doctoral thesis shows that interacting with ingroup or outgroup members, taking decisions publicly or privately, and knowing whether we may interact with others again affect our cooperative behavior. These results highlight the importance of understanding how prosociality may be altered and lay the foundations for policy makers to further those social environments that encourage prosocial behavior. Show less
