Understanding physical models in design cognition: A triangulation of qualitative and laboratory studies

Designers use various kinds of physical models throughout their design process to enhance creativity. The existing literature provides conflicting guidelines about their implementation. The effects of physical models on design cognition remains largely unknown. Prior laboratory studies show that physical models supplement designers' erroneous mental models and thereby lead to higher quality ideas. These prior studies fail to demonstrate any design fixation associated with the use of physical models. In contrast, a few prior observational studies on practicing designers show that the use of physical models causes design fixation. Based on these conflicting results, this study investigates the role of physical models in industry-sponsored projects and in the development of award-winning products through a qualitative research approach. This study explores two hypotheses: The Mental Models Hypothesis - physical models supplement designers' mental models and the Fixation Hypothesis - physical models cause design fixation during the idea generation process. The data are coded qualitatively and then tested quantitatively. The results are triangulated with the results from the prior controlled study. The results provide support to the hypotheses. The differences observed between current and prior studies point to the potential role of the Sunk Cost Effect in engineering idea generation with physical models.