Keeping you at arm’s length: modifying peripersonal space influences interpersonal distance

Peripersonal space represents the area around the body where objects are coded in motor terms for the pur- pose of voluntary goal-directed actions. Previous studies have suggested that peripersonal space is also a safe space linked with our private area, influencing interpersonal space in social contexts. However, whether these two spaces rely on similar embodied processes remains an open issue. In the present study, participants observed a point- light walker (PLW) approaching them from different directions and passing near them at different distances from their right or left shoulder. While approaching, the PLW disappeared at a distance of 2 m and the task for the par- ticipants was to estimate if the interpersonal distance, at the time the PLW would have reached their level, was com- fortable or not. Between two sessions of comfort judg- ments, the participants manipulated a 70 cm tool entailing an extension of peripersonal space, or a 10 cm tool entailing no extension of peripersonal space. The results revealed that the comfortable interpersonal distance was
& Y. Coello yann.coello@univ.lille3.fr
larger when the PLW crossed the mid-sagittal plane of the participants than when it approached them laterally, with a concomitant increase of response time. After participants manipulated the long tool, comfortable interpersonal dis- tance increased, but predominantly when the PLW trajectory implied crossing the participants’ mid-sagittal plane. This effect was not observed when participants manipu- lated the short tool. Two control tasks showed that using the long tool modified the reachability (control 1), but not the time to passage (control 2) estimates of PLW stimuli, suggesting that tool use extended peripersonal space without changing perceived visual distances. Overall, the data show that comfortable interpersonal distance is linked to the representation of peripersonal space. As a consequence, increasing peripersonal space through tool use has the immediate consequence that comfortable interpersonal distance from another person also increases, suggesting that interpersonal-comfort space and peripersonal-reaching space share a common motor nature.
Programme d’Investissements d’Avenir (PIA), Agence Nationale pour la Recherche (Grant ANR-11-EQPX-0023) and the European Founds for the Regional Development (Grant FEDER-Presage 41779).
info:eu-repo/semantics/publishedVersion