Equal kinematics and visual context but different purposes: Observer's moral rules modulate motor resonance

Motor resonance is considered to be an index of the automatic under threshold motor replica of the observed action. Similar actions may be quite different in terms of long-term goals (e.g., grasp to eat vs grasp to throw) and, recently, it has been proposed that the distal goal subtly modulates movements execution, and that observers automatically use these differences in kinematics to discriminate between different intentions. This interpretation is in line with computational approaches proposing that in the agent the generative process causes that intention shapes the kinematics, and in the observer the recognition process causes that the kinematics cues the intention. Given the close entanglement between the two processes, here we investigated whether the mere knowledge of agent's intentions induces in the observer a generative process able to modulate motor resonance. We used transcranial magnetic stimulation to examine motor evoked potentials in the Opponens Pollicis muscle to verify if observer's knowledge of agent's positive, negative, or neutral intentions on a third person influences corticospinal excitability during observation of the same action performed with equal kinematics, and in the same visual context. Results showed that the observation of an action executed with the intention to induce negative effects determined a reduction of motor resonance, revealing the presence of a specific inhibition to reenact an action that results in unpleasant consequences in the other. These data suggest that the information at the intention level activates a generative process which overcomes the replica of kinematics at the goal level, and shapes motor resonance according with observer's mind and not with agent's intention, revealing the possibility of a mere cognitive influence on motor resonance based on individual's ethical values.