Qualitative spatio-temporal calculi play a crucial role in modeling, representing, and reasoning about geospatial dynamics such as the movement of agents or geographic entities. They are ubiquitous in ontological modeling, information retrieval, they play a central part at the human-machine interface, and are critical to process data collected from geosensor networks. What is common to all these application areas is the search for a mechanism to transform data into knowledge borrowing heavily from strategies of (human) cognitive information processing. Astonishingly, there is paucity in actual behavioral evaluations on whether the suggested calculi are indeed cognitively adequate. While the assumption seems to be made that qualitative equals cognitive, a more differentiated view is needed. This paper is filling the void by the first (to the best of our knowledge) behavioral assessment of the DLine-Region calculus using actual dynamic stimuli. These assessments are crucial as the few experiments that exist have clearly demonstrated that topological relations form conceptual groups (clusters), a fact that seems to be highly likely for the 26 DLine-Region relations as well. Our results show which topological relations form (cognitive) conceptual clusters.