Design Fixation in Physical Modeling: An Investigation on the Role of Sunk Cost

Physical models are very commonly used as tools for engineering idea generation, yet the guidelines in literature about their implementation are conflicting. A prior study has shown that physical models have the potential to supplement designers’ erroneous mental models; whereas a few observational studies have shown that physical models can cause a high degree of fixation under certain circumstances. At the same time, a previous controlled study fails to show the presence of fixation in idea generation with physical models. This study hypothesizes that prior observed fixation in physical modeling is due to Sunk Cost Effect, which is the reluctance to choose a different path of action once significant money, time or effort is invested in present one. Consistent with the prior study, this study also hypothesizes that physical models supplement designers’ mental models. These hypotheses are investigated through a controlled between-subject experiment. The results show that cost of building plays a vital role in fixation and fixation is not likely inherent in physical representations. Results also show that physical models supplement designers’ mental models and lead them to higher quality ideas.