Better understanding of rights of children in view of their evolving capacities.
Implementation of child rights in everyday life of children and in children's institutions (daycare centers, schools, and communal facilities for rest, play and cultural activities)
Researcher at the unit "Development and socialization" at the Max Planck Institute for Human Development until 2001 (focus: social development of children in peer groups and friendships). Continued work for the finalization of studies sponsored by the DFG. From 2003 to 2011 elected member of the UN Committee on the Rights of the Child (Geneva). Since that time research, teaching, publications and advisory activities with regard to social development of children, child rights, and implementation of the UN Convention on the Rights of the Child.