The rubber hand illusion (RHI) is a multisensory (visual, tactile, proprioceptive) illusion in which participants report body ownership over, mislocalize actual hand position to, and feel touches applied to, the rubber hand. For many years, researchers have used changes in perceived hand position, measured by inter-manual pointing, as a more objective measure of the illusion than verbal reports alone. Despite this reliance, there is little evidence to show that the illusion of hand ownership is directly related to perceived hand position. We developed an adaptive staircase procedure to measure perceived hand position, and tested whether the RHI affected perceived hand position. In two experiments we found a significant illusion of ownership, as well as significant changes in perceived hand position, but these two measures were uncorrelated. In a third experiment using more typical RHI procedures, we again replicated significant illusions of ownership and changes in hand position, but again the measures were uncorrelated. We conclude that viewing and feeling touches applied to a dummy hand results in clear illusions of ownership and changes in hand position, but via independent mechanisms.
