Action simulation plays a critical role in deceptive action recognition

The ability to infer deception from nonverbal behavior is critical for social interactions. By combining single-pulse and repetitive transcranial magnetic stimulation (TMS), we provide correlational and causative evidence that action simulation is actively involved in the ability to detect deceptive behavior. We recorded motor-evoked potentials during a faked-action discrimination (FAD) task: participants watched videos of actors lifting a cube and judged whether the actors were trying to deceive them concerning the real weight of the cube. Seeing deceptive actions facilitated the observers’ motor system more than truthful actions, suggesting that motor resonance was sensitive to perceived deceits. Furthermore, we found that TMS disruption of inferior frontal cortex (IFC) but not of temporo-parietal junction (TPJ, control site) reduced perceptual sensitivity in the FAD-task. These findings indicate that IFC is necessary for inferring deceits from observed actions and suggest that FAD relies on the simulation of subtle changes in action kinematics.