Grasping affordances with the other's hand: a TMS study

The power of an object to afford a suitable act has been shown to depend on its reachability. Nevertheless, most of our perception and action occur in a social context. Little research has directly explored whether the possibility for other people to act upon an object may affect our processing of its affording features. To tackle this issue, we magnetically stimulated the left primary motor cortex and recorded motor-evoked potentials (MEPs) while participants were presented with a handled object (i.e. a mug) close either to them or to a virtual individual such as an avatar. We found highest MEPs both when the mug was near enough to be actually reachable for the participants and also when it was out of reach for them, provided that it was ready to the avatar’s hand. We propose that this effect is likely to be due to an interpersonal bodily space representation, which plays critical role in basic social interaction.