Incongruent multisensory stimuli alter bodily self-consciousness: Evidence from a first-person perspective experience

In our study, we aimed to reduce bodily self-consciousness using a multisensory illusion (MI), and tested whether this manipulation increases Self-objectification (the psychological attitude to perceive one's own body as an object). Participants observed their own body from a first-person perspective, through a head-mounted display, while receiving incongruent (or congruent) visuo-tactile stimulation on their abdomen or arms. Results showed stronger feelings of disownership, loss of agency and sensation of being out of ones' own body during incongruent compare to congruent stimulation. This reduced bodily self-consciousness did not affect Self-objectification. However, self-objectification (as measured by the appearance of control beliefs subscale of the Objectified Body Consciousness questionnaire) was positively correlated with the MI strength. Moreover, we investigated the impact of MI and Self-objectification on body size estimation. We found systematic body size underestimation, irrespective of type of stimulation or tendency to Self-objectification. These results document a simple yet effective approach to alter bodily self-consciousness, which however spare Self-objectification and body size-perception.