Effect of cognitive load on tactor location identification in zero-g

A wearable haptic interface has been developed to impart vibrotactile information to its user with the goal of improving situation awareness. The effectiveness of the haptic interface has been evaluated in three experiments aboard the NASA KC-135A reduced gravity aircraft. During the third flight, subjects identified the locations of tactors embedded in the haptic display in a microgravity environment. We report our results on how cognitive load affects one's ability to identify the locations of vibrotactile stimulations in the altered-gravity environment. Cognitive load was manipulated by requiring subjects to be strapped to the floor of the KC-135 (low cognitive-load condition) or allowing them to float freely in microgravity (high cognitive-load condition). It was found that tactor-location identification was more accurate in the low cognitive-load condition than in the high cognitive-load condition. Our results have implications for the design of multimodal user interfaces in general.