The study ‘Happy Children, Happy Adolescents’ is a longitudinal study among 1500 children from 22 elementary schools in The Netherlands. The study is designed to identify the impact of social experiences on children’s behavioral, and academic development. Eventually, results forthcoming from this study will contribute to the development of an effective, stepped prevention system, pinpointing the factors that account for the development of problem behavior and academic underachievement at a very early stage.

The study focuses on the following areas of research:

  • socio-emotional development
  • neurocognitive development and social experiences
  • biomarkers of changes in social experiences related to stress psychophysiology (DNA methylation, neuroendocrinology)

Data collection

ailgb31500 children from 22 Dutch elementary schools (about 90 classes) are followed annually since 2011. The annual assessments consist of multiple indicators of adverse social experiences (peer rejection, peer victimization, friendlessness, poor teacher-child relationships) rated by children, peers, teachers, and parents across kindergarten and elementary school. Children and teachers are assessed annually at school by trained interviewers; parents complete questionnaires at home. Furthermore, children’s diurnal cortisol and DNA are sampled repeatedly. Additionally, children are invited to visit the lab for neurocognitive assessments in the focus studies My Brain and My Heart.

In these and other pages you can find some pictures of a test day. These pictures were taken by a photographer of the Vrije Universiteit Amsterdam. The parents of the boy in the photo have given special permission to use these photos. Other children are not photographed. The rights / copyright of the photos belong to the Vrije Universiteit Amsterdam, Faculty of Behavioural and Movement Sciences.


Children and teachers are assessed annually at school by trained interviewers on the following domains:

  • Behavioral and emotional problems via teacher-report and peer nominations
  • Social-emotional development (social competence, emotional competence)
  • Relationships with peers (social preference, sociometric classifications, victimization, friends, friendlessness; peer and teacher report)
  • Teacher-child relationship (conflict and support, child and teacher report)
  • Cognitive development (test scores of visio-spatial working memory, impulsivity, and decision making)
  • Academic development via standardized CITO tracking system

Parents complete questionnaires assessing child behavioral and emotional problems and temperamental difficulties, parenting, family events, stressful life events, parental psychopathology.
Furthermore, at home children’s salivary samples are collected for identification of DNA and basal HPA-axis stress system functioning to test whether changes in social experiences relate to changes in DNA methylation/stress function, and behavioral and academic outcomes.

My Brain: Neural responses during social decision making in children

Children participating in the longitudinal study ‘Happy Children, Happy Adolescents’ are invited to participate in a fMRI study. With this focus study called My Brain, we investigate what the role is of peer rejection on social decision-making in late childhood and what its neural correlates are. In total 50 children around the age of 10 will be tested by trained research assistants. During the fMRI session neural responses during and after social exclusion are recorded, as well as subsequently the neural correlates of social-decision making in the Dictator Game. Moreover, at several time points saliva are collected to assess cortisol and alpha-amylase. Children and their parents report on social experiences (i.e. Social Experience Questionnaire) and problem behavior (e.g. CBCL) respectively, and these data will be compared to the longitudinal data. This study allows us to investigate the influences of social-emotional and cognitive development on the neural responses during social decision-making. If you have any questions about this study, please do not hesitate to contact one of the researchers (Dr. Susanne Koot s.koot@vu.nl or Susanne Asscheman, MSc j.s.asscheman@vu.nl).

My Heart

Children participating in the longitudinal study ‘Happy Children, Happy Adolescents’ are invited to participate in a laboratory study. Peer rejection accounts for profound experiences of stress during childhood and adolescence. One of the underlying mechanisms through which acute peer rejection experiences may be associated with risky decision-making and aggression is stress reactivity. The aim of our focus study ‘My Heart’ is to elucidate the role of acute peer rejection on stress reactivity, risky decision-making and aggression in late childhood. Fifty children around the age of ten will participate in the study.For our purposes a standardized version of the Yale Interpersonal Stressor Child version (YIPS-C) will be combined with an affective decision-making task (Hungry Donkey Task), a risky decision-making task (Balloon Analogue Risk Task) and an aggression task (Noise blast). Heart rate (www.vu-ams.nl) and cortisol responses (in saliva) will be measured continuously throughout the procedure. If you have any questions about this study, please do not hesitate to contact Pia Behnsen, MSc p.m2.behnsen@vu.nl.


VU University, Faculty of Psychology and Education, Department of Developmental Psychology

ZonMW, funds health research and stimulates use of the knowledge developed to help improve health and healthcare in the Netherlands