Proprioceptive Biases in Different Experimental Designs

Systematic biases have been found when matching proprioceptive and visual locations. In this study we investigated whether such visuo-haptic biases depend on the indicator that subjects use and on whether targets are presented on a board (2D) or in free space (3D). Subjects had to move their unseen hand to visually presented targets. They indicated the perceived target position either with their index finger or with a hand-held device, and either on a surface or in free space. We found no differences between the magnitudes of the biases or the directions of the biases. Thus, the results of studies on visuo-haptic biases is not merely dependent on the used experimental designs and can be generalized.