Just before I recognize myself: the role of featural and multisensory cues leading up to explicit mirror self-recognition

Leading up to explicit mirror self-recognition, infants rely on two crucial sources of information: the continuous integration of sensorimotor and multisensory signals, as when seeing one's movements reflected in the mirror, and the unique facial features associated with the self. While visual appearance and multisensory contingent cues may be two likely candidates of the processes that enable self-recognition, their respective contribution remains poorly understood. In this study, 18-month-old infants saw side-by-side pictures of themselves and a peer, which were systematically and simultaneously touched on the face with a hand. While watching the stimuli, the infant's own face was touched either in synchrony or out of synchrony and their preferential looking behavior was measured. Subsequently, the infants underwent the mirror-test task. We demonstrated that infants who were coded as nonrecognizers at the mirror test spent significantly more time looking at the picture of their own face compared to the other-face, irrespective of whether the multisensory input was synchronous or asynchronous. Our results suggest that right before the onset of mirror self-recognition, featural information about the self might be more relevant in the process of recognizing one's face, compared to multisensory cues.