The role of the viewpoint on body ownership

People are more sensitive to detecting asynchrony between a self-generated movement of the hand and delayed visual feedback when what they see matches the expected "self" perspective rather than an "other" perspective (Hoover and Harris in Exp Brain Res 222:389-397, 2012). We take this as corresponding to the ability to distinguish self from others and call it the "self-advantage": a measure of body ownership. What about views of the body that cannot be seen directly? Here, we assessed the effect of familiarity of the view of the body on the self-advantage. Participants performed self-generated hand and head movements viewed directly, in a mirror, and from behind with a variable delay added to the visual feedback. Each view was shown either in the natural perspective or flipped about the vertical or horizontal axes to provide a view from another perspective. Thresholds for detecting a delay in visual feedback were calculated. Dependency of the self-advantage on perspective was most evident for views of the body that are seen most often. Results support the importance of correlating visual feedback with movement information in creating the sense of body ownership.