Disentangling Action from Social Space: Tool-Use Differently Shapes the Space around Us.

Converging evidence suggests close relationships between the action and social space representations. The concepts of peripersonal space, as defined by cognitive neuroscience, and interpersonal space, as defined by social psychology, refer to approximately the same spatial area surrounding our bodies. The aim of this study was thus to assess experimentally whether the peripersonal (PPS) and interpersonal space (IPS) represent a similar psychological entity. Were this true, they should share some functional features. Here we tested tool-use dependent plasticity, known to modulate PPS, but still unexplored in the IPS. Results from two experiments converge in showing that tool-use remapped the action-related PPS, measured by a Reaching-distance toward a confederate, but did not affect the social-related IPS, measured by a Comfort-distance task. These findings indicate that PPS and IPS rely on dissociable plastic mechanisms and suggest that, at least in the present experimental conditions, there is no full functional overlap between these two spatial representations.