Chan, A., MacLean, K. E., McGrenere, J. (2004). "Learning and Identifying Haptic Icons under Workload." Technical Report TR-2004-15, UBC Dept. of Computer Science, Vancouver, 2004. Note: This is an extended version of the paper that appeared at WHC 2005 (above).
This work addresses the use of vibrotactile haptic feedback to transmit background information with variable intrusiveness, when recipients are engrossed in a primary visual and/or auditory task. Our testbed will be a novel urgency-based turn-taking protocol for remote collaboration, and our setup uses inexpensive off-the-shelf technology. We describe two studies designed to (a) perceptually optimize a set of vibrotactile "icons" for our protocol and (b) evaluate users' ability to identify them in the presence of varying degrees of workload. We found that 7 icons learned in approximately 3 minutes were each typically identified within 2.5 s and at 95% accuracy in the absence of workload. With added visual and auditory distractor tasks, the time required to detect a change in haptic icon increased from 1.9 s to an average of 4.3 s. We further provide initial parameters to help designers intelligently balance the need to support communication while minimizing disruption.