End-user customization of affective tactile messages: A qualitative examination of tool parameters

Vibrotactile (VT) signals are found today in many everyday electronic devices (e.g., notification of cellphone messages or calls); but it remains a challenge to design engaging, understandable vibrations to accommodate a broad range of preferences. Here, we examine customization as a way to leverage the affective qualities of vibrations and satisfy diverse tastes; specifically, the desirability and composition of VT customization tools for end-users. A review of existing design and customization tools (haptic and otherwise) yielded five parameters in which such tools can vary: 1) size of design space, 2) granularity of control, 3) provided design framework, 4) facilitated parameter(s), and 5) clarity of design alternatives. We varied these parameters within low-fidelity prototypes of three customization tools, modeled in some respects on existing popular examples. Results of a Wizard-of-Oz study confirm users' general interest in customizing everyday VT signals. Although common in consumer devices, choosing from a list of presets was the least preferred, whereas an option allowing users to balance VT design control with convenience was favored. We report users' opinion of the three tools, and link our findings to the five characterizing parameters for customization tools that we have proposed.