A comparison of "on-thigh" vibrotactile, combined visual-vibrotactile, and visual-only alerting systems for the cockpit under visually demanding conditions

In the cockpit, performance is prone to break down. Conveying crucial information through the tactile modality, which requires little to no additional effort, has been previously examined as means to improve performance and safety. Previously, we demonstrated the ability of the on-thigh vibrotactile alerting display to convey directional cues in the vertical plane. We hypothesized that tactile directional alerting cues would be beneficial in a visually loaded multi-tasking environment. In the current study, two tasks were introduced simultaneously: a directional task where participants respond to directional cues (visual, tactile, or combination of both), and a visual-memory recall task where participants identify, count and recall objects embedded in flight movies. Response time, accuracy and subjective workload were evaluated. Performance in the memory recall task and subjective workload were in favor of the combined tactile & visual configuration. No performance difference was found between visual and tactile & visual in the directional task. We conclude that the tactile & visual configuration may allow operators to choose a strategy in which perceptual and cognitive resources are better utilized.