Biological Motion as an Intuitive and Inviting Non-Symbolic Communication to Improve Human Interaction with Autonomous Systems

As autonomous vehicles become widespread, pedestrians must rapidly infer vehicle motion and yielding intent. Conventional symbolic eHMIs (e.g., text or icons) are language-dependent, culturally variable, and often difficult to detect in complex traffic scenes. We propose a non-symbolic communication framework based on biological motion, implemented as a point-light external human-machine interface (eHMI). In Study 1a (Chinese adults, N = 32), the bio-motion eHMI improved vehicle-movement comprehension relative to text and achieved comparable intent understanding. These benefits generalized to children aged 5–9 (Study 1b) and to a different cultural context (Study 1c). Study 2 showed that the bio-motion eHMI elicited earlier reductions in perceived crossing safety in non-yielding scenarios, supporting safer street-crossing decisions. Study 3 demonstrated enhanced detection distance for acceleration and deceleration changes. Overall, biological motion provides an intuitive, engaging, and culturally robust channel for vehicle-pedestrian communication.