Exploration is an activity that people undertake to broaden their knowledge on a certain topic. In contrast to regular search, which is typically aimed at obtaining a specific answer to a specific question, exploratory search should give a more complete overview of a topic. Further it should enable the discovery of related aspects, such as people, places, times and locations. Exploration demands more time, effort and creativity from the user, but rewards the user with deeper knowledge. Therefore, users need to be stimulated to bring exploration in regular goal-directed search activities. In this paper we present a user study in which we investigate different kinds of exploratory behavior and goals, as well as different kinds of visualizations to support exploration.