Path Following in Non-Visual Conditions.

Path-following tasks have been investigated mostly under visual conditions, that is when subjects are able to see both the path and the tool, or limb, used for navigation. Moreover, only basic path shapes are usually adopted. In the present experiment, participants must rely exclusively on audio and vibrotactile feedback to follow a path on a flat surface. Two different, asymmetric path shapes were tested. Participants navigated by moving their index finger over a surface sensing position and force. Results show that the different non-visual feedback modes did not affect the task's accuracy, yet they affected its speed, with vibrotactile feedback causing slower gestures than audio feedback. Conversely, audio and audio-tactile feedback yielded similar results. Vibrotactile feedback caused participants to exert more force over the surface. Finally, the shape of the path was relevant to the accuracy, and participants tended to prefer audio over vibrotactile and audio-tactile feedback.