Joint attention for pointing but not grasping postures
“Joint attention” refers to changes in one`s own action potentials after observing somebody else’s actions. For example, perceived gaze leads to corresponding attention shifts (Hood et al., 1998; Schuller and Rossion, 2001), and seeing a taskirrelevant pointing arm influences directional judgments (Langton and Bruce, 2000). Observing a grasping movement induces preparation of similar actions (Fadiga et al., 1995), and viewing grasping hands facilitates congruent manual responses (Craighero et al., 2002). Viewpoint-independent action simulation through “mirror neurons” has been suggested as the neural substrate for such joint attention effects (Decety and Grezes, 1999; Gallese, 2001; Gallese and Goldman, 1998). Here we show that joint attention facilitates encoding of visual information from the target locations of intended actions. The effect is viewpointindependent and does not seem to generalize to completed actions.