Do visual body-ownership cues modulate visuo-tactile temporal order judgements?: An investigation in non-synaesthetes and mirror-touch synaesthetes

To accurately perceive oneself in a complex multisensory environment, the brain has to determine which unimodal signals originated from its own body and should therefore be integrated. It is currently debated if visual body-ownership cues such as object form and orientation interact, and if visual plausibility increases the effects of various multisensory signals being integrated. In this thesis, I investigated the effects of visual body-ownership cues on visuo-tactile temporal perception in both non-synaesthetes and mirror-touch synaesthetes using a temporal order judgement (TOJ) task. Each participant viewed videos of a touch being applied to visual stimuli that were either plausible or implausible for his or her right hand (hand oriented plausibly, hand rotated 180 degrees, sponge). On each trial, a touch was also applied to the participant's own hand at varying stimulus onset asynchronies (SOAs) relative to the visual touch. Participants judged which stimulus came first: viewed or felt touch. I tested whether visual body-ownership cues affect temporal binding and the size of the temporal interval between visual and tactile stimuli participants can reliably notice ('just noticeable difference' - JND). Bayesian analyses revealed that plausibility of object form and orientation do not affect visuo-tactile temporal perception in either non-synaesthetes or mirror-touch synaesthetes. I discuss the implications of these findings in relation to understanding body perception and mirror-touch synaesthesia.