Sensitivity to Conflict between Visual Touch and Tactile Touch

The two point discrimination test is a well known means of assessing tactile sensory acuity. In this paper, we describe a similar test wherein one point of stimulation is tactile and the other one is visual. We propose this test to measure how vision and taction combine to form a unified touch percept, in the presence of sensory conflict. We perform the test at the leg above the knee, using virtual reality to render the visual “touch” while the real touch occurs by means of a monofilament. The results are compared with those obtained from a traditional two point discrimination test performed at the same location. This information can be used to understand how to allocate tactors in a haptic feedback array as well as to better inform the design of future virtual reality accessories.