'Am I moving?' An illusion of agency and ownership in mirror-touch synaesthesia.

Mirror-touch synaesthesia (MTS) is a condition that leads people to experience tactile sensations on their own body when watching at someone else being touched. Recent accounts postulate that MTS is linked with atypical self-other representations. It has been suggested that this may be associated with disturbances in two main components of self-awareness: sense of agency and sense of ownership. This study investigates changes in sense of agency and sense of ownership in MTS. Using a paradigm that deliberately blurs the boundaries between the self and the other, we not only found that MTS affects sense of agency and sense of ownership, but that these aspects of self-awareness are affected differently. We suggest that alterations in sense of agency can be linked to more profound disturbances in sense of ownership in MTS, and that MTS may be characterised by underlying difficulties in self-other processing.