In this interdisciplinary discussion on mental models, researchers from various areas in cognitive science tackle the following questions: What is a mental model? What are the prospects and limitations in applying the mental model notion in cognitive science? How can the ideas on the nature of mental models and their mode of operation be empirically substantiated? The primary goal of the research group was to work out a definition of mental models that embraces the overall use of this construct in cognitive science as well as the more specific conceptions used in particular research domains...