Characterizing the Sense of Embodiment: the Development of a Sensorimotor Robotic Platform

Embodiment is the experience of owning and controlling our bodies. It is a product of cognitive sensorimotor integration processes and by manipulating what we see and feel, we can extend the perceived boundaries of our bodies to include non-biological objects. Consequently, it is of interest to many human-robotic control applications that aim to promote the seamless interaction of the human user and machine. The sense of embodiment has three constituent components that robotic systems may engage with: the Sense of Ownership (SoO), the Sense of Agency (SoA), and our peripersonal space (PPS). Despite the recognition that each is linked to the other, how these components interact to form a cohesive sense of embodiment remains poorly understood. To address this issue, in this work, we designed an embodiment research platform that allows us to explore the relationships between the SoO, SoA, and PPS. We developed a sensorimotor interface, experimental setup, and protocol in which a robotic hand mirrored the actions of the participants' real hand. Participants performed a series of grasping tasks in which we manipulated the cutaneous sensations they experienced and the position of the robot relative to their body. We then employed multiple independent measures of SoO, SoA, and PPS. Our results indicated that (1) cutaneous feedback improved all three components of embodiment, and (2) there appeared to be multiple complex interrelationships among the three components and their measures.