Abstract
Gaze position has previously been found to affect the perceived location of visual, auditory, proprioceptive and tactile targets. This is compatible with the idea that perceived target location, regardless of modality, is coded in a visual reference frame and that the gaze angle is systematically underestimated in the coordinate transformations involved in the coding of location. We investigated whether touches to parts of the body that are not in view are also coded in a visual reference frame. Vibrotactile stimuli of 250 Hz and 50 ms duration were applied to the arm, front and back of the torso and to the forehead while the head and/or eyes were held eccentrically. Participants then centered their head and eyes before reporting the perceived location of the touch relative to a visual scale. Perceived touch location was shifted in the same direction as eccentric gaze position for all of the body parts tested, regardless of whether the body part was viewable (arm, front of torso) or not (back, forehead). Eye and head position had equivalent effects, even when the touch was applied to the head. These observations support the idea that touch is first coded in an internal representation of the body that is static and in a canonical position before being recoded into a visual reference frame. Overall, our data suggest that the entire body is coded visually, regardless of whether the body part is viewable.
Meeting abstract presented at VSS 2012