Visually Guided Haptic Search

In this study we investigate the influence of visual feedback on haptic exploration. A haptic search task was designed in which subjects had to haptically explore a virtual display using a force feedback device and to determine whether a target was present among distractor items. While the target was recognizable only haptically, visual feedback of finger position or possible target positions could be given. Our results show that subjects could use visual feedback on possible target positions even in the absence on feedback on finger position. When there was no feedback on possible target locations, subjects scanned the whole display systematically. When feedback on finger position was present, subjects could make well-directed movements back to areas of interest. This was not the case without feedback on finger position, indicating that showing finger position helps forming a spatial representation of the display. In addition, we show that response time models of visual serial search do not generally apply for haptic serial search. Consequently, in tele-operation systems, for instance, it is helpful to show the position of the probe even if visual information on the scene is poor