Study of tactile guidance of the hand in a pointing task by means of a vibrotactile device

Vibrotactile devices convey messages by presenting vibrations on the user’s skin. In recent years, interest in and applications of vibrotactile devices have been growing. The proverbial tap-on-the-shoulder draws an individual’s attention to the direction of the tapping. Because the spatial coordinates of a localised stimulus on the skin are very well represented in the nervous system, the stimulation of the skin may be a powerful way of communicating spatial information, such as the direction of objects or events (for example, see Schrope 2001). Vibrotactile devices consisting of fitting out vibrating elements on various body locations allow spatial guidance. Among successful applications with relatively simple displays are the Van Erp and Van Veen device (Van Erp and Van Veen 2004), which presented directions from an incar navigation system by means of vibrating elements under the left and right legs, and Rochlis and Newman (2000) presented directional information during simulated extravehicular activity in space by means of vibrating elements located on the torso and the neck. More complex displays, consisting 60 (or more) vibrating elements, cover the entire torso of the user. These torso displays not only present the left and right directions, but also map eight or more external directions in the horizontal plane. The power of this ‘tap-on-the-shoulder’ principle is shown, for example, in a helicopter hovering task (Rupert 2000; Van Erp et al. 2003). In order to design a vibrotactile device able to transmit directional information for gesture guidance or navigation, the present study investigated the efficiency of a prototype to guide the hand in a pointing task. More specifically, in a blind experiment, the performances obtained using tactile coding are compared to those obtained using verbal instructions.