Keywords:

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.