A Study to Understand Perceptual Discrepancies Using Visual Illusions and Data Envelopment Analysis (DEA)

There are often discrepancies in how a product is perceived in the different display media employed in typical product development processes. Product developers in many cases rely on different display media for design realizations. This study investigates if and how perceptual discrepancies change across different media and design groups. An experiment was designed and conducted at Virginia Tech to compare the perceptual differences of a simplified model of a car across three types of representation media: industrial design sketches, Computer aided design (CAD) models, and physical prototypes. The geometry of the car window was varied to simulate two visual illusions; architrave and irradiation. Two groups (industrial designers and engineers) with varying levels of experience (students and professionals) were studied. The experimental results were analyzed by applying a two-step data envelopment analysis (DEA) approach to identify the trends of how the shape perception varied within and across the subject groups. This study and its findings are particularly important in several ways. First, the DEA approach provides an objective comparison of groups when differences in the participants' evaluation skills and experience levels should be explicitly taken into account, important to understanding student learning and effectiveness of practitioners. Our study has shown that designers' perceptual evaluation strategies change significantly across the groups. Findings of this study can be used for understanding perceptual discrepancies across media and groups in product design and development and could help to inform new approaches to design education research.