Rubber hands do not cross the midline

The rubber hand illusion (RHI) occurs when a person misattributes a fake hand as his or her own hand. Previously, the RHI has been examined with both the rubber hand and the participant's real hand uncrossed with regards to the participant's midline. The present study examined the strength of the illusion when the real hand, the fake hand or both hands are placed across the body midline. The illusion was induced by stroking the rubber hand and the real hand simultaneously. Asynchronous brushing served as a comparable condition since the RHI is not seen under these circumstances. Participants indicated where they felt their real hand was located by marking a sheet of paper under the table on which their unseen hand was placed. A significant RHI was observed with both the hands uncrossed. In contrast, no RHI was present when either hand was crossed over the midline. Additionally, a shift in hand judgment towards the midline was observed when participants crossed their real hand. These results indicate the importance of the midline in understanding representations of the body. (C) 2011 Elsevier Ireland Ltd. All rights reserved.