New paper in press: Tobias Heed, Johanna Möller, and Brigitte Röder: Movement induces the use of external spatial coordinates for tactile localization in congenitally blind humans, to appear in Multisensory Research.
We and others have often found that people who were born blind process touch differently than people who can see. Sighted people automatically compute where a touch is in space, that is, they combine the location of the touch in the skin, and where the touched body part currently is. Congenitally blind people don’t seem to do the same. Instead, they mostly rely just on the location of the touch on the skin, unless they really have to derive the location in space. Given these differences, the visual system is apparently important for how we perceive touch.
We did indeed find that blind humans code touch differently while they move than while they are still. And, as we had suspected, they seem to derive a location for touch in space in this situation. Yet, this spatial location appears to be of much higher relevance to sighted than to blind people.
Therefore, our results confirm that whether you can see or not critically influences the way you perceive touch. However, how we code touch is also affected by movement.