Tie my hands, tie my eyes

Previous studies have demonstrated that motor abilities allow us not only to execute our own actions and to predict their consequences, but also to predict others' actions and their consequences. But just how deeply are motor abilities implicated in action observation? If an observer is prevented from acting while witnessing others' actions, will this impact on their making sense of others' behavior? We recorded proactive eye movements while participants observed an actor grasping objects. The participants' hands were either freely resting on the table or tied behind their back. Proactivity of gaze behavior was dramatically impaired when participants observed others' actions with their hands tied. Since we don't literally perceive actions with our hands, the effect may be explained by the hypothesis that effective observation of action depends not only on motor abilities but on being in a position to exercise them. This suggests, for the first time, that actions are observed best when we are actually in the position to perform them