Effects of button design characteristics on performance and perceptions of touchscreen use

Abstract Touchscreen technology has gained increasing popularity in both personal and public settings. However, button design characteristics that may affect touchscreen use have not been fully investigated. The aim of this study was to examine the effects of button design characteristics (i.e., button size, button spacing, visual feedback and button shape) on users’ touchscreen performance, mental workload and preference. Twenty participants participated in an experiment in which they performed both digit and letter input tasks. Button sizes ranged from 7.5 to 27.5 mm with 5-mm increments, while button spacing was absent, 1 mm or 3 mm. Two types of visual feedback (presence and absence) and three button shapes (square, horizontal and vertical rectangles) were examined. Results indicated that button size, button spacing and button shape yielded significant effects on touchscreen performance, while visual feedback had no effect. It is also found that users performed better with medium-to-large size (17.5 mm and larger), square buttons. Mental workload was comparable across button shapes. Users generally preferred button design characteristics that could yield optimal input performance. Relevance to industry The findings could facilitate the optimal design of usable touchscreen technology.