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
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
The overarching goal of this thesis was to examine the behavioral, computational, and neural mechanisms underlying social learning in adolescence. The first aim was to examine developmental... Show moreThe overarching goal of this thesis was to examine the behavioral, computational, and neural mechanisms underlying social learning in adolescence. The first aim was to examine developmental patterns across adolescence of two forms of social learning: (1) learning about other people, specifically, whether they are (un)cooperative and (un)trustworthy, and (2) learning for other people (prosocial learning) to know what actions may benefit or help others. I made use of multiple experimental paradigms based on well-known economic games and/or probabilistic reinforcement learning paradigms to assess these forms of social learning. Secondly, I aimed to examine underlying mechanisms and factors that account for age-related and individual differences in social learning. Applying computational modeling and functional neuroimaging as additional tools contributed to a better understanding of the underlying mechanisms and how these develop across adolescence. The findings in this thesis converge to early-to-mid adolescence as a key developmental period for developing well-adjusted social behaviors, and especially in the cooperative domain there are pronounced improvements. These studies make an important contribution to the literature on social development and learning, and may eventually contribute to interventions targeted at promoting well-adjusted behavior in typically developing adolescents, as well as youth with maladaptive social tendencies. Show less
This thesis consists of three empirical chapters that investigate elements of human social behavior, adherence to and violations of social norms, and the computational and neurological... Show moreThis thesis consists of three empirical chapters that investigate elements of human social behavior, adherence to and violations of social norms, and the computational and neurological underpinnings thereof. I focus on three behavioral paradigms in particular – the attacker-defender contest, the trust game, and the ultimatum game – which model asymmetrical conflicts, generosity and reciprocity, and norms of fairness, respectively. Ultimately, each chapter acts as a building block contributing a different perspective to the study of human sociality. Using economic games, computational models based on the principle of utility, and model-based neuroimaging, my research contributes to the scientific endeavor working to crack the “elaborate and secret code that is written nowhere, known by none, and understood by all” (Sapir, 1927, p.137) Show less
People diagnosed with Borderline Personality Disorder (BPD) continuously struggle with knowing who they are and maintaining relationships. Fortunately, psychotherapies for BPD have proven effective... Show morePeople diagnosed with Borderline Personality Disorder (BPD) continuously struggle with knowing who they are and maintaining relationships. Fortunately, psychotherapies for BPD have proven effective. However, not everyone benefits from treatment with particular challenges remaining in social relations and finding meaning in life. Therefore, it is important to understand how we can better support people with BPD.We know that identity disturbances relate to interpersonal difficulties but we do not really understand how. Therefore, we investigated how interactions with others are influenced by how people see themselves, in the general population and in people diagnosed with BPD. To this end, we studied brain activation and the role of childhood trauma and low self-esteem. In addition, we investigated whether self-views can be strengthened using positive memories.We found that the way people respond to critiques and compliments relates to how positive or negative they see themselves. Moreover, vivid positive memories can benefit mood and self-esteem. However, people with BPD seem to not sufficiently distance themselves from critiques nor engage in positive memories and compliments. Finding the right balance between distance from critiques and engagement with a positive self-image may break the cycle of negative self-knowledge and contribute to better social interactions. Show less
Peer influence plays a crucial role in the rise of health-risk behaviors during adolescence. However, there is increasing evidence that peer influence can also lead to positive psychosocial... Show morePeer influence plays a crucial role in the rise of health-risk behaviors during adolescence. However, there is increasing evidence that peer influence can also lead to positive psychosocial outcomes, such as prosocial behavior. The main goal of this thesis was to investigate peer influence on risk-taking and prosocial behavior in adolescence and to unravel its underlying neural processes. Findings showed that effects of peers on risk-taking behavior are dependent on the context. Adolescents take into account both social norms from peer feedback and the uncertainty associated with outcomes in risky decisions. Moreover, peers can both increase and decrease prosocial behavior in typically developing (TD) adolescents and those with autism spectrum disorders (ASD), illustrating that peer influence can also lead to more adaptive outcomes. Finally, we studied the neural processes underlying prosocial peer feedback and results indicate that prosocial peer influence is underlined by the social brain network, regions involved in thinking about the self and others. Eventually, the results of this thesis can contribute to interventions aimed at decreasing risk-taking and promoting prosocial behavior in adolescence, with possibly long lasting effects into adulthood. Show less
This thesis focused on the development of creative thinking across adolescence and into adulthood. To this end, a range of creativity tasks, both with and without an fMRI scanner, and before and... Show moreThis thesis focused on the development of creative thinking across adolescence and into adulthood. To this end, a range of creativity tasks, both with and without an fMRI scanner, and before and after training paradigms has been used to ex_amine both age- and experience-related effects on creative thinking performance during functional brain develop_ment. Chapter 1 provides a theoretical background for the research described in chapters 2 to 6. In Chapter 2, developmental trajectories of creative cognition across adolescence and early adulthood were examined using a set of tasks gauging both insight and divergent thinking in the verbal and visual domain. In Chapter 3, behavioral and neural differences for creative problem solving in middle-adolescents and adults were examined. Chapter 4 examined the neural correlates of divergent thinking in adults and adolescents. Chapter 5 focused on the effectiveness of creative ideation training in adolescents and adults. In Chapter 6, the benefits of training creativity in adolescents were examined using fMRI techniques. Finally, Chapter 7 summarizes the main results of the empirical studies presented in this thesis. Here, implications of the results are discussed and suggestions for future research are presented. Show less
Adolescence, defined as the transition phase between childhood and adulthood, is a time of many physical, cognitive and social-emotional changes. It is a natural time of exploring, thrill seeking,... Show moreAdolescence, defined as the transition phase between childhood and adulthood, is a time of many physical, cognitive and social-emotional changes. It is a natural time of exploring, thrill seeking, and for eventually setting long-term goals and aspirations. One of the most prominent findings is that adolescents take more risks than children or adults. The focus of this thesis is on adolescent risk taking behavior. The goal is to identify individual difference factors that are related to risk taking behavior and assess how these variables change over development. Adolescence is associated with major changes in hormonal levels, brain function and social environment. In this thesis it is tested how changes in pubertal development, brain function and social environment together influence real life risk taking. The studies in this thesis show that neural responses to rewards in the striatum are elevated during adolescence. This response is influenced by chronological age, pubertal development, personality and the social context. Importantly, the striatum response to rewards is related to real life risk taking behavior and therefore has functional relevance. The results of this thesis provide vital insight in the complex relationship between reward processing and real life risk taking behavior. Show less
Children and adolescents who are chronically rejected by their peers suffer from widespread impairments in daily life, ranging from poor academic achievement and dropping out of school, to... Show moreChildren and adolescents who are chronically rejected by their peers suffer from widespread impairments in daily life, ranging from poor academic achievement and dropping out of school, to delinquency and the development of mental health problems. To gain a better understanding of the developmental processes that give rise to such impairments, the research described in this dissertation examined the neurocognitive underpinnings of processes that play a role in the emergence and maintenance of peer group rejection and acceptance. The first part of this dissertation focuses on neurocognitive processes underlying reactions to social exclusion. The second part concentrates on the neurocognitive processes involved in sharing valuable resources, based on the widely established finding that frequent displays of prosocial behaviors, such as cooperating, helping, and sharing, are associated with both gaining and maintaining acceptance among peers. The empirical work in this dissertation demonstrates that a developmental cognitive neuroscience approach provides unique insights into the emotional, regulatory, and socio-cognitive processes thought to play a role in the emergence and maintenance of peer group acceptance and rejection. Show less
This thesis aimed to investigate the neurobiological mechanisms of adolescent onset depression and anxiety disorders. A longitudinal fMRI study design was used that included both task related brain... Show moreThis thesis aimed to investigate the neurobiological mechanisms of adolescent onset depression and anxiety disorders. A longitudinal fMRI study design was used that included both task related brain activation and resting state functional connectivity. All participants were scanned three times in a six-month period. In between scan sessions the adolescents from the clinical group received treatment as usual. Adolescents from the control group were scanned within the same time interval but did not receive treatment. During a scan session several MRI parameters were collected including task based fMRI (emotional face processing task) and resting state fMRI. We also administered several questionnaires about derpession and anxiety symptomatology. It was demonstrated that adolescents with depressive and anxiety disorders show differentiating patterns of amygdala reactivity and connectivity compared to a healthy control group. Furthermore, using a dimensional approach and taking individual differences in self-reported depression and anxiety symptoms into account highlighted the role of self-reported anxiety symptoms in amygdala reactivity during emotional faces processing. These findings indicate that the amygdala indeed is an important region involved in emotional face processing and that focusing on this region can provide further insights in the development and persistence of depressive and anxiety disorders in adolescents. Show less
One of the most prominent changes in adolescence is social reorientation. In other words, adolescents develop more intimate relationships with peers, they discover what it is like to be involved in... Show moreOne of the most prominent changes in adolescence is social reorientation. In other words, adolescents develop more intimate relationships with peers, they discover what it is like to be involved in a romantic relationship, and they take (social) risks by for example showing risky driving in the presence of friends. Given that social networks with peers become central elements in the adolescent’s life, investigating the role of individual differences related to the development of social reorientation seems highly relevant. This dissertation contributes to a better understanding of stability and change in social reorientation during adolescence by explaining the crucial role of empathy in social interactions from a brain and behavioral perspective. Future research can benefit from the presented studies by applying it to a more detailed analysis of individual differences in this important period in life, which may help to explain why some adolescents are successful in developing social competencies and relationships, whereas others experience difficulties. Eventually, this may lead to the development of interventions for youth who do not cope well with the social requirements from the environments, and help to improve their lives and the lives of individuals around them Show less
The aim of this thesis was to identify the neural mechanisms that enable a person to adaptively respond to, and recover from stress, which was studied in healthy controls, in people with increased... Show moreThe aim of this thesis was to identify the neural mechanisms that enable a person to adaptively respond to, and recover from stress, which was studied in healthy controls, in people with increased vulnerability or resilience to stress-related disorders, and in people with depression or PTSD, using magnetic resonance imaging (MRI). In most of the studies, a specific MRI method was employed, with which it is possible to assess how different brain regions communicate with each other (i.e., functional connectivity) when the brain is initiating or regulating stress responses. Structure, activity, and connectivity of the amygdala, a small brain region important for stress reactivity, was of main interest. The results show how stress influences information processing, and causes changes in the communication between brain areas, even long after the stressful event ended. Furthermore, personality dimensions associated with increased vulnerability or resilience to affective disorders were associated with changes in brain networks involved in emotion processing and regulation. Finally, smaller amygdala volumes were found in women with PTSD, while reduced integrity of affective brain networks was demonstrated in depression. Together, these results open important new avenues for future research into the short and long term effects of stress on the brain. Show less
Self-control abilities are crucial for successful functioning in daily life. At the core of self-control lies the ability to intentionally inhibit one__s actions. Intentional inhibition differs... Show moreSelf-control abilities are crucial for successful functioning in daily life. At the core of self-control lies the ability to intentionally inhibit one__s actions. Intentional inhibition differs from externally driven inhibition in that it is driven by an internal thought process rather than an external stimulus that tells one to stop. The goal of this thesis was to examine the development of intentional inhibition and compare this with externally driven inhibition. In order to investigate the covert process of intentional inhibition, the research described in this thesis made use of neurobiological measures such as phasic heart rate changes and functional magnetic resonance imaging (fMRI). In addition, to learn more about self-control in context, the final empirical chapter examined intentional and externally driven inhibition in the context of relevant and irrelevant emotions. Show less
Previous research has revealed that it is important for people to be moral. Nevertheless, they may sometimes commit immoral acts. In this dissertation, I examined when people tend to act in ways... Show morePrevious research has revealed that it is important for people to be moral. Nevertheless, they may sometimes commit immoral acts. In this dissertation, I examined when people tend to act in ways that are considered moral; whether it is important for them to be perceived as moral by others; and how much they care whether or not they succeed in behaving according to their moral values. Additionally, I used neuroscientific (i.e., EEG and fMRI) and psychophysiological (i.e., skin conductance) research methods to gain insight in some of the processes underlying these questions. Extending previous research by examining people's actual moral behavior and shedding light on the cognitive and affective processes underlying their acts, the findings in this dissertation reveal not only that, but also when and how people behave according to their moral values. Show less
The present thesis contains five experimental studies into the effects of stress on memory I healthy males. Hydrocortisone (and propranolol) administration or the induction of social stress are... Show moreThe present thesis contains five experimental studies into the effects of stress on memory I healthy males. Hydrocortisone (and propranolol) administration or the induction of social stress are used to heighten cortisol levels, and consequently to study its effects on working memory performance and memory retrieval. In addition, by using neutral and emotional distraction during working memory, effects of cortisol on emotional distraction were investigated, also with use of functional imaging. Overall, it was consistently found that high cortisol levels, by hydrocortisone administration or induced by stress, reduced the distraction by emotional irrelevant stimuli, hence improving working memory. The current findings might be relevant for patients suffering from posttraumatic stress disorder, who typically suffer from trauma-related intrusions. Show less
Top-down guidance of behavior in a complex and dynamically changing world is often based on information held in working memory. Such guidance serves to bias decision-making processes in directions... Show moreTop-down guidance of behavior in a complex and dynamically changing world is often based on information held in working memory. Such guidance serves to bias decision-making processes in directions consistent with externally set rules or internally maintained intentions. Orthogonal to this goal-driven guidance, decisions may be biased also by stimulus-driven factors, such as the automatic reactivation of episodic associations that accompanied the current stimulus in a previous instance. We investigated whether top-down and bottom-up processes account for variation in context based decision making as measured by the AX-CPT in a behavioral [1] and fMRI study [2]. Moreover, several behavioural studies have indicated that transiently induced positive affect modulates control processes in context-based decision making, generally leading to enhanced flexibility. Using ERPs in a classic AX-CPT, we studied the temporal dynamics of a positive affect induction on control processes in context-based decision making [3]. Additionally, we studied learning the associations between a situation, the response to it, and the outcome of that decision and the effect of basal ganglia modulations on this learning process by means of a Parkinson’s patient study. Studies [1] and [2] pointed out that in decisions with rapidly changing environmental demands, goal-driven preparation is often beneficial but may also hamper performance which can be overcome by applying increased control. Moreover, this top-down bias is regulated more efficiently when the specific stimulus is presented in the same context it was previously associated with, compared to when it is presented in a new and unusual context. Additionally, fMRI study shed light on the way these stimulus-driven performance changes may be represented in the brain. Study [3] showed that a positive affect induction influenced reactive and evaluative components of control (indexed by the N2 elicited by the target, and by the Error-Related Negativity elicited after incorrect responses) in an AX-CPT task, whereas cue-induced preparation and maintenance processes remained largely unaffected (as reflected in the P3b and the Contingent Negative Variation components of the ERP). The patient studies suggest that moderate dopaminergic medication and STN stimulation in Parkinson’s patients [chapter 5,6] both improve learning functions relying on caudate and putamen. However, the improvement induced by dopaminergic medication largely depended on individual patient characteristics. Show less
