Contents lists available at ScienceDirect Applied Ergonomics journal homepage: www.elsevier.com/locate/apergo The role of individual differences on perceptions of wearable fitness device trust, usability, and motivational impact Michael A. Rupp * , Jessica R. Michaelis, Daniel S. McConnell, Janan A. Smither University of Central Florida, USA ARTICLE INFO Keywords: Wearable fitness device Technological trust Usability Motivation Individual differences ABSTRACT Lack of physical activity is a severe health concern in the United States with fewer than half of all Americans meeting the recommended weekly physical activity guidelines. Although wearable fitness devices can be ef- fective in motivating people to be active, consumers are abandoning this technology soon after purchase. We examined the impact of several user (i.e. personality, age, computer self-efficacy, physical activity level) and device characteristics (trust, usability, and motivational affordances) on the behavioral intentions to use a wearable fitness device. Novice users completed a brief interaction with a fitness device similar to a first pur- chase experience before completing questionnaires about their interaction. We found computer self-efficacy, physical activity level, as well as personality traits indirectly increased the desire to use a fitness device and influenced the saliency of perceived motivational affordances. Additionally, trust, usability, and perceived motivational affordances were associated with increased intentions to use fitness devices. 1. Introduction Interest in wearable fitness technology is increasing rapidly and many people believe that these devices will increase their motivation to exercise and ability to achieve fitness and health goals (Consumer Technology Association, 2013). Wearable fitness technologies include devices that continuously monitor wearers' physical activity (e.g., steps, calories) and physiological data (e.g., heart rate, skin temperature) throughout the day (Mackinlay, 2013; Mancuso et al., 2014). Prior research has also suggested these fitness devices will become an integral component of a more personalized forthcoming healthcare system that will allow patients and physicians to access a continuous stream of health data (Odubogun, 2015) while increasing individuals’ daily physical activity levels. However, while their effectiveness has been validated (e.g., Butryn, et al., 2016; Strath et al., 2011; Mercer et al., 2016), the acceptance of this technology is limited as up to one-third of purchasers stop using their devices within six months of ownership (Ledger and McCaffrey, 2014). A recent longitudinal study of Fitbit devices found 25% of participants dropped out after the first week and 50% dropped out after the second week of the study (Shih et al., 2015). Long-term adoption is a critical concern that needs to be addressed in order for this technology to be beneficial. The current study investigates three primary concerns that were cited as potential sources of disuse of these devices: 1) lack of motivational ability, 2) poor design and us- ability, and 3) lack of trust in the technology (Ehmen et al., 2012; Lazar et al., 2015; Mancuso et al., 2014; Shih et al., 2015) called device characteristics. The current study also examines how user character- istics (individual differences in age, personality, and computer self-ef- ficacy) predict user perceptions of each of the device characteristics. Finally, we also compare how user and device characteristics relate to behavioral intentions to use fitness technology in the future. 1.1. Motivational ability of the device People are generally motivated to complete behaviors that achieve their needs or goals. One motivational theory, Self-Determination Theory (SD-Theory), theorizes that people have three core psycholo- gical needs: autonomy, competence, and relatedness. Activities that meet these needs will be seen as intrinsically rewarding and will mo- tivate individuals to engage in them long term (Deci and Ryan, 2000; Ryan and Deci, 2000). Autonomy is the need to make meaningful choices and be in control. Competence is the need to be skillful, ef- fective, meet challenges, and achieve goals. Finally, relatedness is the need to feel connected to others and have social support (Ryan and Deci, 2000). Further, when these needs are ignored or incorrectly im- plemented, individuals may be demotivated instead (Ryan and Deci, 2000). This may lead to disuse of the devices. Zhang (2008) used the term motivational affordances to signify properties of a technology that are aligned with motivational theory to support the user's needs or goals. A wearable device with high https://doi.org/10.1016/j.apergo.2018.02.005 Received 3 November 2016; Received in revised form 29 April 2017; Accepted 7 February 2018 * Corresponding author. Department of Psychology, University of Central Florida, Orlando, FL 32816, USA. E-mail address: mrupp@knights.ucf.edu (M.A. Rupp). Applied Ergonomics 70 (2018) 77–87 0003-6870/ © 2018 Elsevier Ltd. All rights reserved. T