The case of Dr. Jekyll and Mr. Hyde: a kinematic study on social intention.

The aim of the present study was to investigate the effects of social intentions on action. Participants (N=13) were requested to reach towards, grasp an object, and either pass it to another person (social condition) or put it on a concave base (single-agent condition). Movements' kinematics was recorded using a three-dimensional motion analysis system. The results indicate that kinematics is sensitive to social intention. Movements performed for the 'social' condition were characterized by a kinematic pattern which differed from those obtained for the 'single-agent' condition. Results are discussed in terms of a motor simulation hypothesis, which assumes that the same mechanisms underlying motor intention are sensitive to social intentions.