Triggering social interactions: chimpanzees respond to imitation by a humanoid robot and request responses from it

Even the most rudimentary social cues may evoke affiliative responses in humans and promote socialcommunication and cohesion. The present work tested whether such cues of an agent may also promotecommunicative interactions in a nonhuman primate species, by examining interaction-promoting behavioursin chimpanzees. Here, chimpanzees were tested during interactions with an interactive humanoid robot, whichshowed simple bodily movements and sent out calls. The results revealed that chimpanzees exhibited twotypes of interaction-promoting behaviours during relaxed or playful contexts. First, the chimpanzees showedprolonged active interest when they were imitated by the robot. Second, the subjects requested ‘social’responses from the robot, i.e. by showing play invitations and offering toys or other objects. This study thusprovides evidence that even rudimentary cues of a robotic agent may promote social interactions inchimpanzees, like in humans. Such simple and frequent social interactions most likely provided a foundationfor sophisticated forms of affiliative communication to emerge.