5. Discussion and conclusions
The objective of this study was to gain an understanding of the perceived differences between degrees of softness of a touchscreen display and input devices in terms of user task performance and satisfaction. The aim was to provide designers with practical implications for the design of mobile devices and their accessories to ensure a pleasant haptic experience. This study utilized a gaming task instead of a Fitts’ reciprocal tapping task, measured task performance in terms of both task completion time and visual search time, and analyzed RTs for correct trials in an attempt to generalize the findings of the experiment to real-life settings and to lead participants toward a focus on differences in haptic sensation. The block-tapping game, wherein participants needed to perform a visual search for the next numbered block to tap, closely mirrors everyday situations where mobile phone users repeat information-seeking and acquisition behaviors by searching for the target information and selecting it, or by pressing buttons to navigate while using commercialized apps and browsing the Internet. This method was expected to encourage participant engagement in the experimental task and to predict real-world task performance. The sample of participants involved in this experiment included a majority of non-stylus users and a minority of stylus users, who all had a capacitive touchscreen-based smartphone and are comparable to the general population.
As mentioned in the literature review, the relationship between the touchscreen and styli with varying softness was identical to the interaction between textured paper and different tools. During this experiment, all participants experienced the stage of “pre-interaction” (Sulaiman and Blandford, 2004) by tapping their own palms, the touchscreen, or the table with their fingers or the different styli when they were ready to start performing the tasks. The more unusual they found the combination of input device and interface and the less experience they had using them, the more they tended to inspect the appearance of the nib and shaft of the styli and the surface of the interfaces. These observations suggest that designers should carefully consider the visual properties of touchscreens and input devices, including their shape, appearance, surface texture, and thickness, because such properties allow users to form expectations of the results of interaction. Furthermore, the participants also experienced the “post-interaction”