Abstract:
Robots that can talk with humans play increasingly important roles in society. However,
current conversation robots remain unskilled at eliciting empathic feelings in humans. To address
this problem, we used a robot that speaks in a voice synchronized with human vocal prosody. We
conducted an experiment in which human participants held positive conversations with the robot
by reading scenarios under conditions with and without vocal synchronization. We assessed seven
subjective responses related to affective empathy (e.g., emotional connection) and measured the
physiological emotional responses using facial electromyography from the corrugator supercilii and
zygomatic major muscles as well as the skin conductance level. The subjective ratings consistently
revealed heightened empathic responses to the robot in the synchronization condition compared
with that under the de-synchronizing condition. The physiological signals showed that more positive
and stronger emotional arousal responses to the robot with synchronization. These findings suggest
that robots that are able to vocally synchronize with humans can elicit empathic emotional responses.