Robots with tears can convey enhanced sadness and elicit support intention

The behaviour of shedding tears is a uniquely human expression of emotion. Human tears have an emotional signal to convey sadness and a social signalling function to elicit support from others. However, it is not clear whether the tears shed by robots have the same signalling function as those of humans. Therefore, the aim of this study was to investigate whether the tears of communication robots have the same emotional and social signalling function as those of humans. Tear processing was applied to pictures of robots to create pictures of them without and with tears, which were used as visual stimuli. In Study 1, participants were asked to respond to a picture of a robot by indicating the intensity of emotion they thought the robot was experiencing. The results showed that adding tears to the robot's picture significantly increased the intensity of sadness. Study 2 measured supportive intentions towards the robot by presenting a picture of the robot and a scenario. The results showed that adding tears to the robot's picture also increased support intention. Therefore, the results of this study indicate that robot tears have the same emotional and social signalling functions as that of humans.