The case-study is conducted in four playrooms of The Glaxo Wellcome Child Development Center (North Carolina, USA). It consists of an assessments and a series of observations per room. The theory of activity centers was used as the theoretical frame. It focuses on providing an environment for selfdirected learning and thus enables us to study the environment-behavior interaction from an educational point of view. Self-directed learning means that the children can choose their own activity out of a range of possibilities provided. An activity center has five defining attributes: (1) a physical location, (2) visible boundaries, (3) work and sitting surfaces, (4) storage and (5) display of materials. When the playroom is set up by using activity centers, a diverse palette of possibilities is provided to the children in a clear, understandable and attractive way. The building occupants, children and teachers, are chosen as the focus of this study. The teachers ere involved through discussions and little exercises. The transfer of knowledge from researcher to the teachers was an important part of the evaluation. The assessment of the playrooms mainly focused on two aspects. First, the quality of the activity centers was assessed by denoting the number of physical borders, the display of materials and the available working surfaces. The overall quality of the centers was good. Second, the availability of children's places was assessed. A playroom, as well as the entire building, must provide places for children that differ in atmosphere, by stimulating different senses of the children. In this respect the playrooms were not very well equiped. The observations consisted of eighteen time samples (with intervals of five minutes) for each playroom. Besides the place of the child, additional information was denoted. The categories 'behavior related to the activity center' and 'behavior not related to the activity center' were introduced in the observation system to be able to discuss whether the centers send clear cues to the children, so they start activities in the areas set up for the specific activities. To discuss the observations, hypotheses were formulated. One hypothesis was clearly supported by the data: Moving and wandering children are observed in less well defined activity centers and the circulation areas of the playroom. This is a confirmation of the theory. The search for support for the theory of activity centers was successful only to a certain extend. Some evidence of the positive effects of the application of the theory of activity centers was found.