Reshaping the Peripersonal Space in Virtual Reality

Peripersonal space (PPS) refers to the space around us that lies within reach, in which most of our interactions with the environment occur. However, the PPS is not a static bubble surrounding our body. Rather, it can be dynamically reshaped in size, for instance as a consequence of the use of tools extending the arm’s reach. Here we employed a visuo-tactile detection task in an immersive VR environment to measure the size of participants’ PPS before and after different kinds of tool training. A short training period in which participants pulled objects from the Extrapersonal space (EPS) towards themselves via a tool was effective in enlarging the PPS, a result that nicely complements previous studies carried out in real life studies. However, no significant change in PPS size was achieved via training with other motor routines such as pulling, hammering or shooting, each of which involving a different kind of interaction between the agent and the targets. Taken together, our results suggest that the reshaping of the PPS is a complex phenomenon in which the kind of motor routines exploited to interact with the surrounding objects, plays a critical role.