Pfeiffer, C. (2015). Multisensory Spatial Mechanisms of the Bodily Self and Social Cognition - A Commentary on Vittorio Gallese and Valentina Cuccio

This commentary aims to find the right description of the pre-reflective brain mechanisms underlying our phenomenal experience of being a subject bound to a physical body (bodily self) and basic cognitive, perceptual, and subjective aspects related to interaction with other individuals (social cognition). I will focus on the proposal by Gallese and Cuccio that embodied simulation, in terms of motor resonance, is the primary brain mechanism underlying the pre-reflective aspects of social cognition and the bodily self. I will argue that this proposal is too narrow to serve a unified theory of the neurobiological mechanisms of both target phenomena. I support this criticism with theoretical considerations and empirical evidence suggesting that multisensory spatial processing, which is distinct from but a pre-requisite of motor resonance, substantially contributes to the bodily self and social cognition. My commentary is structured in three sections. The first section addresses social cognition and compares embodied simulation to an alternative account, namely the attention schema theory. According to this theory we pre-reflectively empathize with others by predicting their current state of attention which involves predicting the spatial focus of attention. Thereby we derive a representational model of their state of mind. On this account, spatial coding of attention, rather than motor resonance, is the primary mechanism underlying social cognition. I take this as a theoretical alternative complementing motor resonance mechanisms. The second section focuses on the bodily self. Comparison of the brain networks of the bodily self and social cognition reveals strong overlap, suggesting that both phenomena depend on shared multisensory and sensorimotor mechanisms. I will review recent empirical data about altered states of the bodily self in terms of self-location and the first-person perspective. These spatial aspects of the bodily self are encoded in brain regions distinct from the brain network of embodied simulation. I argue that while motor resonance might contribute to body ownership and agency, it does not account for spatial aspects of the bodily self. Thus, embodied simulation appears to be a necessary but insufficiently “primary” brain mechanism of the bodily self and social cognition. The third section discusses the contributions of the vestibular system, i.e., the sensory system encoding head motion and gravity, to the bodily self and social cognition. Vestibular cortical processing seems relevant to both processes, because it directly encodes the world-centered direction of gravity and allows us to distinguish between motions of the own body and motions of other individuals and the external world. Furthermore, the vestibular cortical network largely overlaps with those neural networks relevant to the bodily self and social cognition. Thus, the vestibular system may play a crucial role in multisensory spatial coding relating the bodily self to other individuals in the external world.