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

Author(s):  
Vimal Viswanathan ◽  
Julie Linsey

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.

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Vimal K. Viswanathan ◽  
Julie S. Linsey

Researchers and design practitioners advocate building physical models of ideas at early stages of the design process. Still, the cognitive effects of physical models remain largely unknown. Some studies show that physical models possess the potential to facilitate the generation of high quality ideas. Conversely, other studies demonstrate that physical models can lead to design fixation. A prior controlled study by the authors failed to detect fixation due to early stage physical models. Based upon these conflicting results, this study hypothesizes that the fixation observed in prior studies can be explained by the Sunk Cost Effect. The Sunk Cost Effect pertains to an individual's reluctance to choose a different path of action once he/she invests a significant cost (money, time, or effort). According to this theory, as designers spend more time, money or effort in building physical models, they tend to generate ideas with lower novelty and variety. The prior observational studies use complicated design problems with higher costs compared to the controlled study, possibly explaining the difference in results. This study also hypothesizes that physical models supplement designers' erroneous mental models. The authors investigate these hypotheses through a controlled, between-subject experiment with five conditions: Sketching Only, Metal Building (low time cost), Plastic Building (high time cost), Metal Constrained Sketching, and Plastic Constrained Sketching. In each condition, subjects construct their ideas using materials specified by the name of the condition. The constrained sketching conditions assist in determining if participants tend to limit their ideas to only ones that can be built with given materials even though they are instructed to write down all ideas. The results confirm that the sunk cost of building plays a vital role in the observed fixation; thus, physical models do not inherently cause fixation. Moreover, results also show that physical models supplement designers' erroneous mental models, leading to higher quality ideas. To minimize sunk costs very early in the design process, models should be built with materials requiring minimal time, cost, and effort for the designers.


Author(s):  
Vimal K. Viswanathan ◽  
Julie S. Linsey

Engineering idea generation is a critical part of new product development and physical models are one tool used in this phase of design. Unfortunately, few guidelines about the effective use of physical models to support idea generation exist. The advantages and disadvantages of physical models need to be clarified so that engineers know when and where to implement them effectively. Previous literature indicates there is potential for design fixation on physical prototypes. This limits the solutions considered. In contrast, other recommendations encourage the extensive use of physical models and the psychological literature indicates that physical representations have the potential to lead to more feasible design by supporting designers’ mental models of physical phenomena. This study evaluates these questions with a between-subjects experiment with four conditions, sketching only, building, building & testing, and constrained sketching. No evidence for design fixation is observed. The results show that physical models supplement designers’ mental models, thereby leading to higher quality ideas (fraction of functional ideas). This result shows a potential way of improving designer’s innovation by strategically implementing fast and cheap prototyping methods.


2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Vimal K. Viswanathan ◽  
Julie S. Linsey

Engineering idea generation is a crucial part of new product development, and physical modeling is a widely used tool. Despite the physical models’ popularity in the idea generation process, little is known about their effects on design cognition. The existing literature provides contradicting guidelines about their use in the design process. Product design firms call for the frequent use of physical models, but some studies suggest that physical models induce design fixation. The psychological literature indicates that physical representations, by supporting designers’ mental models of physical phenomena, might lead to more feasible designs. The advantages and disadvantages of physical models as idea generation tools need to be clarified to help designers decide when and where to implement them. Based on prior studies and anecdotal evidence, two hypotheses are tested: (1) physical models supplement designer’s mental models and (2) physical models induce design fixation. Two between-subject idea generation experiments with novice designers are conducted to evaluate these hypotheses. In the first pilot experiment, the participants generate ideas in three conditions: sketching only, building, and building and testing. This study is followed by a second experiment, in which a new condition called constrained sketching is added. In each condition, participants use the representation implied by the name of the condition. The percentage of ideas satisfying all design requirements indicates the physical models’ effect on the designers’ mental models. Novelty and variety are used as metrics for design fixation. The percentage of functional ideas quantified shows significant variation across the sketching and building conditions, whereas novelty and variety show no differences. These results support the argument that physical models supplement novice designer’s mental models. No evidence of fixation is observed, which contradicts the results of the prior observational studies. Hypothesized reasons for the apparently contradictory results are also presented.


2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Christine A. Toh ◽  
Scarlett R. Miller

Interacting with example products is an essential and widely practiced method in engineering design, yet little information exists on how the representation (pictorial or physical) or interaction a designer has with an example impacts design creativity. This is problematic because without this knowledge we do not understand how examples affect idea generation or how we can effectively modify or develop design methods to support example usage practices. In this paper, we report the results of a controlled study with first year engineering design students (N = 89) developed to investigate the impact of a designer's interaction with either a two-dimensional (2D) pictorial image or a three-dimensional (3D) product (through visual inspection or product dissection activities) and the resulting functional focus and creativity of the ideas developed. The results of this study reveal that participants who interacted with the physical example produced ideas that were less novel and less functionally focused than those who interacted with the 2D representation. Additionally, the results showed that participants who dissected the product produced a higher variety of ideas than those that visually inspected it. These results contribute to our understanding of the benefits and role of 2D and 3D designer-product interactions during idea development. We use these findings to develop recommendations for the use of designer-product interactions throughout the design process.


2013 ◽  
Vol 37 (1) ◽  
pp. 44-51
Author(s):  
David Bessell

This article outlines a hybrid approach to the synthesis of percussion sounds. The synthesis method described here combines techniques and concepts from physical modeling and convolution to produce audio synthesis of percussive instruments. This synthesis method not only achieves a high degree of realism in comparison with audio samples but also retains some of the flexibility associated with waveguide physical models. When the results are analyzed, the method exhibits some interesting detailed spectral features that have some aspects in common with the behavior of acoustic percussion instruments. In addition to outlining the synthesis process, the article discusses some of the more creative possibilities inherent in this approach, e.g., the use and free combination of excitation and resonance sources from beyond the realms of the purely percussive examples given.


2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Vimal K. Viswanathan ◽  
Julie S. Linsey

Engineering idea generation plays a vital role in the development of novel products. Prior studies have shown that designers fixate to the features of example solutions and replicate these features in their ideas. This type of fixation acts as a major hindrance in idea generation, as it restricts the solution space where designers search for their ideas. Building upon the study by Linsey et al. [2010, “A Study of Design Fixation, Its Mitigation and Perception in Engineering Design Faculty,” ASME Trans. J. Mech. Des., 132, 041003], this study hypothesizes that designers fixate to example features and this fixation can be mitigated using certain defixation materials including alternate representations of the design problem. To investigate this, the experiment conducted by Linsey et al. [2010] with engineering design faculty is replicated with novice designers. Participants generate ideas for a design problem in three groups: one group working with a fixating example, a second group working with the same example along with alternate representations of the design problem and a control group. The obtained results show that both the novice designers and design faculty fixate to the same extent, whereas the defixation materials have differential effect on the two groups. This result indicates that design researchers need to be very careful in developing methods and guidelines that are formulated and tested with studies on novice designers. The effectiveness of such measures may vary with the level of expertise of the designer.


Author(s):  
Vimal Viswanathan ◽  
Julie Linsey

Engineering idea generation plays a vital role in the development of novel products. Prior studies have shown that designers fixate to the features of example solutions and replicate these features in their ideas. This is a major hindrance in idea generation as it restricts the solution space where designers search for their ideas. This study hypothesizes that though expert designers fixate to example features, they still can outperform novices in terms of quantity of ideas as they have a larger set of knowledge acquired through their experience. To investigate this, the experimental by Linsey et al. is replicated for novice designers. Novices generate ideas for a design problem in three groups: one group working with a fixating example, a second group working with the same example along with alternate representations for the design problem and a control group only presented with the problem and no additional materials. The obtained results support the hypothesis. Both novice and expert designers are fixated to the example features, but the expert designers generated more nonredundant ideas. The alternate representations of the design problem help experts in mitigating their fixation, whereas in novices, these have no effect.


2019 ◽  
Author(s):  
Danny Schnerwitzki ◽  
Christian Hayn ◽  
Birgit Perner ◽  
Christoph Englert

AbstractNeuronal networks commonly referred to as central pattern generator (CPG) networks coordinate the generation of rhythmic activity like locomotion and respiration. These networks are proposed to exhibit a high degree of homology in their development. Their establishment is influenced by a variety of transcription factors. One of them is the Wilms tumor protein Wt1 that is present in dI6 neurons of the ventral spinal cord, which are involved in the coordination of locomotion. Here we report about the so far undescribed presence of Wt1 in neurons of the caudoventral medulla oblongata and their impact on respiration. By performing marker analyses, we were able to characterize these Wt1 positive (+) cells as dB4 neurons. The temporal pattern of Wt1 occurrence suggests a role for Wt1 in the differentiation of dB4 neurons during embryonic and postnatal development. Conditional knockout of Wt1 in these cells caused an altered population size of V0 neurons already in the developing hindbrain leading to a decline in the respiration rate in the adults. Thereby, we confirmed and extended the so far proposed homology between neurons of the dB4 domain in the hindbrain and dI6 neurons of the spinal cord in terms of development and function. Ablation of Wt1+ dB4 neurons resulted in the death of neonates due to the inability to initiate respiration suggesting a vital role for Wt1+ dB4 neurons in breathing. These results extend the role of Wt1 in the CNS and show that in addition to its function in differentiation of dI6 neurons it also contributes to the development of dB4 neurons in the hindbrain that are critically involved in the regulation of respiration.


2017 ◽  
Author(s):  
Kari Gaalswyk ◽  
Mir Ishruna Muniyat ◽  
Justin L. MacCallum

AbstractBiomolecular structure determination has long relied on heuristics based on physical insight; however, recent efforts to model conformational ensembles and to make sense of sparse, ambiguous, and noisy data have revealed the value of detailed, quantitative physical models in structure determination. We review these two key challenges, describe different approaches to physical modeling in structure determination, and illustrate several successes and emerging technologies enabled by physical modeling.HighlightsQuantitative physical modeling is emerging as a key tool in structure determinationThere are different approaches to incorporate physical modeling into structure determinationModeling conformational ensembles and making sense of sparse, noisy, and ambiguous data are two challenges where physical modeling can play a prominent role


2014 ◽  
Vol 4 (2) ◽  
pp. 113-121 ◽  
Author(s):  
Stephanie Chow ◽  
Stephen Yortsos ◽  
Najmedin Meshkati

This article focuses on a major human factors–related issue that includes the undeniable role of cultural factors and cockpit automation and their serious impact on flight crew performance, communication, and aviation safety. The report concentrates on the flight crew performance of the Boeing 777–Asiana Airlines Flight 214 accident, by exploring issues concerning mode confusion and autothrottle systems. It also further reviews the vital role of cultural factors in aviation safety and provides a brief overview of past, related accidents. Automation progressions have been created in an attempt to design an error-free flight deck. However, to do that, the pilot must still thoroughly understand every component of the flight deck – most importantly, the automation. Otherwise, if pilots are not completely competent in terms of their automation, the slightest errors can lead to fatal accidents. As seen in the case of Asiana Flight 214, even though engineering designs and pilot training have greatly evolved over the years, there are many cultural, design, and communication factors that affect pilot performance. It is concluded that aviation systems designers, in cooperation with pilots and regulatory bodies, should lead the strategic effort of systematically addressing the serious issues of cockpit automation, human factors, and cultural issues, including their interactions, which will certainly lead to better solutions for safer flights.


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