Dealing with individual variability: When telling what is real depends on telling who is acting

► Observing other people's actions allows decoding social messages. ► Movement speed is often critical, and affected by inter-individual variability. ► Implicit detection of identity (self vs. other) precedes overt movement analysis. ► Perception is differently tuned to explore variations in self vs. other actions. ► A broader range of natural speeds is expected when watching others.