Recent studies have reported an intricate interplay between affordance and mirror effects (the imitation of an-
other agent) when participants attend to the concurrent presentation of an object and another agent interacting
with it. In the present paper, we compare two experimental settings in which an observed action was presented
as a prime for a task involving the categorization of a graspable object. In experiment 1a, the action depicted a
reach and grasp gesture whereas in experiment 1b, only the reach phase was presented. This modification led
to very different outcomes. Experiment 1a reflected the traditional imitation effect elicited by human motion.
Conversely, experiment 1b showed the facilitation of contralateral responses. Affordance effects were found in
experiment 1a only for the RVF. Our results support the view that motor simulation processes underlying imita-
tion or joint actions are extremely sensitive to specific phase kinematics.