  Robot interfaces often only use the visual channel. Inspired by Wickens'
Multiple Resource Theory, we investigated if the addition of audio elements
would reduce cognitive workload and improve performance. Specifically, we
designed a search and threat-defusal task (primary) with a memory test task
(secondary). Eleven participants - predominantly first responders - were
recruited to control a robot to clear all threats in a combination of four
conditions of primary and secondary tasks in visual and auditory channels. We
did not find any statistically significant differences in performance or
workload across subjects, making it questionable that Multiple Resource Theory
could shorten longer-term task completion time and reduce workload. Our results
suggest that considering individual differences for splitting interface
modalities across multiple channels requires further investigation.
