Multisensory disintegration and the disappearing hand trick

Abstract

Summary Successful multisensory integration is the cornerstone of corporeal awareness. Experimental investigations of body ownership usually require the embodiment of additional non-bodily objects [1,2]. In contrast, here we asked whether experimentally-induced disintegration of sensory signals could bring about loss of ownership and awareness for the real limb without the embodiment of an alternative representation. In three experiments, naive participants placed their hands inside a MIRAGE multisensory illusions box and reached across to touch their right hand with their left. In the crucial Disappearing Hand condition, we created a situation in which the right hand unexpectedly disappeared from vision and touch with the result that healthy participants reported the sensation that they had no right hand and that their hand was no longer part of their body. In two further experiments, physiological responses to threat towards the disappeared hand were absent and self-drawn representations of the limb terminated at the wrist. These results highlight the importance of bottom-up processes in the normal experience of body permanence and may provide the key to understanding neuropsychological disorders of body ownership.