Designing haptic icons to support collaborative turn-taking

This paper describes research exploring the use of haptics to support users collaborating remotely in a single-user shared application. Mediation of turn-taking during remote collaboration provides a context to explore haptic affordances for background communication as well as control negotiation in remote collaboration: existing turn-taking protocols are rudimentary, lacking many communication cues available in face-to-face collaboration. We therefore designed a custom turn-taking protocol that allows users to express different levels of urgency in their request for control from a collaborator; state of control and requests are communicated by touch, with the intent of offloading visual attention. To support it, we developed a set of haptic icons, tangible stimuli to which specific meanings have been assigned. Because we required an icon set which could be utilized with specified, varying levels of intrusiveness in real attentionally challenged situations, we used a perceptually guided procedure that consisted of four steps: initial icon set design, perceptual refinement, validation of learnability and effectiveness under workload, and deployment in an application simulation. We found that our haptic icons could be learned to a high degree of accuracy in under 3min and remained identifiable even under significant cognitive workload. In an exploratory observational study comparing haptic, visual, and combined haptic and visual support for our protocol, participants overall preferred the combined multi-modal support, and in particular preferred the haptic support for control changes and the visual support for displaying state. In their control negotiation, users clearly utilized the option of requesting with graded urgency. The three major contributions in this paper are: (1) the introduction and first case study using a systematic process for refining and evaluating haptic icons for background communication in a primarily visual application; (2) the usability observed for a particular set of icons designed with that process; and (3) the introduction of an urgency-based turn-taking protocol and a comparison of haptic, visual and multi-modal support of our implementation of that protocol. r 2007 Published by Elsevier Ltd.