Process modeling constitutes a fundamental task in the context of process-aware information systems. Besides process model creation, the reading and understanding of process models is of utmost importance. To better understand the latter, we have developed a conceptual framework focusing on the comprehension of business process models. By adopting concepts from cognitive neuroscience and psychology, the paper presents initial results from a series of eye tracking experiments on process model comprehension. The results indicate that experiences with process modeling have an influence on overall model comprehension. In turn, with increasing process model complexity, individuals with either no or advanced expertise in process modeling do not significantly differ with respect to process model comprehension. The results further indicate that both groups face similar challenges in reading and comprehending process models. The conceptual framework takes these results into account and provides the basis for the further experiments.