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The Influence of the “Decoy Effect” on the Engineering Design Process

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2012 ASEE Annual Conference & Exposition


San Antonio, Texas

Publication Date

June 10, 2012

Start Date

June 10, 2012

End Date

June 13, 2012



Conference Session

Design Cognition II

Tagged Division

Design in Engineering Education

Page Count


Page Numbers

25.1316.1 - 25.1316.9



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Paper Authors


Joseph C. Musto Milwaukee School of Engineering

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Joe Musto is a professor of mechanical engineering and Director of the Mechanical Engineering Program at Milwaukee School of Engineering, He holds a B.S. from Clarkson University (Potsdam, N.Y.), and both a M.Eng. and Ph.D. from Rensselaer Polytechnic Institute (Troy, N.Y.).

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Alicia Domack Milwaukee School of Engineering

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The Influence of the “Decoy Effect” on the Engineering Design ProcessEngineering students are educated in formal design methodologies to aid in the decision-makingprocesses involved in the creation of new products and systems. These formal methodologiesmake use of such design tools as decision matrices to aid engineering teams in the evaluation andselection of a design solution from the various alternatives considered for development.The Decoy Effect (or Asymmetrically Dominated Alternative Effect), is a well-studiedphenomenon that affects decision-making. In essence, it describes the experimentally-verifiedeffect that occurs when an inferior choice is introduced to the available alternatives. Thisinferior choice is said to be “dominated” by one of the original alternatives, which then promptsindividuals to choose the dominating alternative (Ariely, 2010; Slaughter, 1999). The effect ofthis so-called “decoy” choice often leads the decision-maker to the selection of a suboptimalalternative. .For example, consider a car buyer who has decided there are two qualities that are equallyimportant in a purchasing decision, cost and fuel economy. The buyer has narrowed the searchto the following vehicles:Car Fuel Economy PriceA 28mpg $17,500B 38mpg $24,500It is expected that either alternative could be chosen because there is a balance between cost andfuel economy. However, consider the same decision with another alternative thrown into theselection pool:Car Fuel Economy PriceA 28mpg $17,500B (target) 38mpg $24,500C (decoy) 38mpg $26,500The choice is now made easier because the decoy is asymmetrically dominating one alternative,in this case, choice B. Individuals are now more likely to choose car B, because it is clearlysuperior to car C.The decoy effect has been shown to adversely affect decision-making capabilities involvingconsumer product purchases, gambling, apartments, and job offers (Heath & Chatterjee, 1995;Highhouse, 1996; Wedell, 1991). While the impact of this effect would certainly extend todecision-making among technical professionals, there has been little attempt to address theimpact on the decision-making process used by engineers in design.This paper introduces the decoy effect and describes the implications it can have on theengineering design process. Initial small-scale experiments to validate and quantify the effect asit relates to engineering design will be described. Development and modification of design toolsto mitigate the impact of the decoy effect in the engineering design process will be described.

Musto, J. C., & Domack, A. (2012, June), The Influence of the “Decoy Effect” on the Engineering Design Process Paper presented at 2012 ASEE Annual Conference & Exposition, San Antonio, Texas. 10.18260/1-2--22073

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