How wearable haptic devices impact hand embodiment in virtual reality – preliminary results

Manipulation in virtual environments is usually difficult because users lack the haptic feedback which might be necessary to orient themselves and the objects they are manipulating (Mine, 1998). We report results of an experiment where we evaluate whether haptic feedback can improve embodiment of a virtual hand. Subjects were standing in front of a display while the subject’s left hand was underneath the screen and thus hidden from their view. An infrared camera acquired hand motion and a virtual hand on the screen mimicked the hidden hand’s movement with an offset of 15 centimeters to the right. Subjects wore a glove with haptic feedback devices on thumb and index finger. They were asked to put virtual cubes on a moving virtual target. Touching a virtual object caused vibrotactile feedback, force feedback or no feedback. These conditions were provided both synchronously and asynchronously. Each subject passed all six conditions in a computer controlled random order. After each condition, subjects were asked to click the mouse with their right hand on the position of their left index finger to measure the proprioceptive drift (PPD). Afterward, they were asked to fill out the embodiment questionnaire by Longo (2008). Pre-test results indicate that subjective embodiment was significantly higher when haptic feedback was provided. Moreover, the PPD was significantly larger with force feedback compared to the conditions with vibrotactile feedback or no feedback. Results indicate that force feedback might improve body schema integration such as PPD and subjective embodiment when interacting with virtual hands.