Mental workload of guiding devices: directional pulling forces, vibrotactile stimuli and audio cues

Asymmetric vibrations are known to produce a pulling sensation when stimulating the human hand. This effect has been exploited as a means of guidance. We conducted a user study to compare asymmetric vibrations, simple vibration, and sound cues for guidance in terms of task completion time and mental workload. Mental workload was evaluated (N=22) using the dual-task paradigm with a Stroop test and arithmetic operations test as secondary tasks. Audio cues improved significantly the task completion time for baseline and stroop tasks compared to the other methods. No significant differences were found for the reaction time for the guiding task. The use of audio cues was evaluated as the less mentally demanding guiding method on the NASA-TLX questionnaire.