The Effect of Prototyping and Critical Feedback on Fixation in Engineering Design

The Effect of Prototyping and Critical Feedback on Fixation in Engineering Design Trina C. Kershaw 1 , Katja Holtta-Otto 2 , & Yoon Soo Lee 3 tkershaw@umassd.edu, kotto@umassd.edu, ylee@umassd.edu Departments of 1 Psychology, 2 Mechanical Engineering, and 3 Design, University of Massachusetts Dartmouth 285 Old Westport Road, North Dartmouth, MA 02747 USA method (Pahl & Beitz, 1996) to compare the concepts for a next-generation alarm clock of freshmen and senior mechanical engineering students. They found that freshmen and senior groups produced concepts with similar, high levels of feasibility. However, freshmen students were less fixated on the sample alarm clocks than seniors. Instead of just attempting to promote divergent thinking at the beginning of the design process, engineers need to avoid fixation throughout the design process. Abstract Design fixation is a common problem in engineering. In two experiments, we implement two educational interventions, prototyping and critical feedback, to help reduce design fixation, which is defined as adherence to one's own design. We found that constant prototyping across the design process reduced fixation in the final product. Surprisingly, we also found that not receiving feedback reduced fixation in the final product. Implications for engineering design education are discussed. Keywords: fixation; engineering; prototyping; feedback; metacognition; education Avoiding Fixation through Prototyping The typical engineering design process involves coming up with a few ideas, quickly selecting one, and taking that idea through the design cycle (Ulrich & Eppinger, 2004). Prototyping is a common part of engineering design. We loosely define prototyping as a representation of a design idea before the final artifact exists (Lim et al., 2008). In the beginning of the process rough prototypes can be used to capture latent customer needs and to prove a concept. During the design process the level of detail of the prototypes improves and they are used for communicating concepts to the client, testing the usability, and exploring and evaluating the design (Lim et al., 2008). A prototype can ensure the final product will work as desired and it can answer questions that would be otherwise hard to answer. Prototyping has many benefits, and thus prototyping is common in most design projects. Design requires the mental manipulation of complex relationships among design features, thus taxing cognitive capacity (Youmans, 2011). Prototypes could reduce fixation by releasing cognitive load. Youmans found that using prototypes reduced fixation compared to situations in which participants, both design experts and undergraduate psychology students, were unable to manipulate objects. The point at which prototypes are used during the design process might also influence creativity. For example, Jang and Schunn (2010) found that engineering designers who used prototypes during the ideation phase produced more innovative designs. However, use of prototypes during the concept refinement phase had no impact on innovation. Despite these reported positive effects of prototyping, there is evidence that exposure to prototypes can lead to design fixation during concept generation (Christiansen & Schunn, 2007; 2009). We varied the point at which prototyping occurred during the design process in Experiment 1. One of the greatest challenges facing future engineers is to create innovative products to stay competitive in the real world (Duderstadt, 2008). Unfortunately, there is considerable evidence that current engineering curricula may not support creativity. Graduating engineers are often less innovative than entering freshman (Yang, 2008) and the standard design process tools often lead to safe rather than innovative solutions (Cooper, 2005). Engineers tend to stick with the same idea throughout the design cycle (Ulrich & Eppinger, 2004), often even if the idea has severe flaws. In the following paper, we review possible hindrances to creativity in engineers, and describe two educational interventions that we hope can lead to greater creativity in engineering design. The Problem of Design Fixation in Engineering Being stuck is common in design. One means of measuring ‘stuckness’ is measurement of design fixation, the unintentional adherence to a set of features or concepts limiting the output of conceptual design (Janson & Smith, 1991). Design fixation is typically measured as similarity to the design brief the designers were shown in the beginning of the design project. However, designers can also show fixation on concepts learned outside of the experimental setting (Purcell & Gero, 1996) or to the initial idea they had (Sachs, 1999). Design fixation is a prevalent problem in engineering, yet it is often unrecognized by the person committing it; even teachers of engineering design are unaware of their own fixation (Linsey et al., 2010). Numerous creativity methods have been proposed to overcome design fixation. These methods generally focus on one-time generation of ideas at the beginning of the design process, which is not enough (cf. Mehalik & Schunn, 2006) because innovative design should be a continuous string of divergent and convergent thinking (Dym et al., 2005). For example, Genco et al. (2010) used the 6-3-5 Avoiding Fixation through Reflecting on Critical Feedback