Reactive Chameleon: A Method to Mimic Conversation Partner’s Body Sway for a Robot

Along with improvements in information processing capabilities and development of machine learning, research that robots provide services instead of people is progressing. In order to raise satisfaction with the service provided by the robot, it is important to build a robot that makes it easy for people to talk and can get a good impression from people. In human–human interaction, mimicking the conversation partner’s motion is one of the factors that influence the impression from the conversation partner. The influence coming from the mimicking in the interaction is called the “chameleon effect”. As the chameleon effect, it is known that a person unconsciously mimics interaction partner’s nonverbal behavior, in addition, it is also known that a good impression can be obtained from the interaction partner by consciously mimicking the partner’s nonverbal behavior without being noticed. Previous studies have shown that the chameleon effect occurs also even in human–robot interaction by mimicking interaction partner’s nonverbal behavior, and interaction partner has good impression on the robot. However, considering the conversation scene, there are problems with the method verified in the previous research when robots mimic interaction partner’s nonverbal behavior. The first problem is that the robot cannot perform gestures using its arms and head at the same time as mimicking nonverbal behavior during conversation. The second problem is that the conversation partner may notice that the robot mimics his/her nonverbal behavior during the conversation. In this thesis, we propose “Reactive Chameleon”, a method to generate body sway for a robot that based mimicking a conversation partner’s body sway. Reactive Chameleon designed for a robot to get a good impression from the conversation partner by chameleon effect without disturbing robot gestures. In Reactive Chameleon, the volume of the mimicking is dynamically adjusted to the conversation partner and the adjusted robot’s sway merged with robot’s own body sway for the conversation partner not to notice that robot mimics his/her body sway. We conducted an experiment to verify that the impression that the participant has toward the robot is affected by having a conversation with a robot that mimics a participant’s body sway. Results of the experiment show that the robot that imitates body sway with Reactive Chameleon got high evaluation from the conversation partner by chameleon effect.