The Thin Line between Self and Others: Interpersonal Multisensory Stimulation may change self-identity and self-other perception

Interpersonal Multisensory Stimulations (IMS) may blur the distinction between self and others and induce self-other merging. Indeed, experiencing tactile facial stimulation while seeing similar synchronous stimuli delivered to the face of another individual provokes the illusory experience of ownership of the other’s face and a bias in attributing to the self facial features of the other. This effect is influenced by - and induces -positive interpersonal perception of the synchronously stimulated other. Here we tested the hypothesis that experiencing IMS: 1) changes the neural representation of the self, making it similar to the other (Study 1); 2) is dependent upon how individuals define the self in relation to others, i.e. self construal (Study 2). By recording Event Related Potentials from the Self- and Other face after participants experienced IMS, we found that IMS modulates the Late Positive Potential, a reliable electrophysiological marker of self-identification process. IMS cancels out the difference in LPP amplitudes recorded at baseline from the Self and the Other face. By recording self-construal (SCS; Singelis 1994) and empathic traits (IRI; Davis, 1980) of participants experiencing facial IMS, we found that an interdependent (i.e. when the self is fundamentally connected to and defined by close relationships with others) - but not independent – self construal positively predict self-other merging, a relationship partially mediated by other-oriented empathic traits. These results advance our knowledge in delineating the inter-individual factors that influence the extent to which we include others’ features - and induce analogous changes- in the notion of the self.