Recognizing humor is still too complicated for robots, according to Divesh Lala, one of the Japanese scientists involved in this research. That is why the researchers opted for an approach in which the robots respond to a smile from their interlocutor. This ‘shared laughter’ gave people the impression that the robot is showing more empathy for them, according to publication in the scientific journal Frontiers in Robotics and AI.
Not every smile can be answered with a shared smile, emphasize the researchers at Kyoto University. In addition, they also differentiated between different types of laughter, such as a ‘social laugh’ (a polite laugh in which no humor is involved) or a ‘happy laugh’ (a slightly louder laugh of happiness).
Based on data from ‘speed dates’ between male students and the robot called ‘ERICA’, the Japanese trained the robot’s system in three steps. First recognizing a human smile, then deciding when to smile, and finally determining which smile type best suits the situation.
Four different conversations
To test ERICA’s laughing skills, the researchers created four different conversations lasting two to three minutes. In each conversation, the Japanese compared the new smile system to scenarios where ERICA responded only with a “social smile” or no smile at all. Each sound clip was then assessed by 130 volunteers for empathy, naturalness, human similarity and understanding. The ‘shared smile system’ scored the highest on all components.
‘We hope that in the future ERICA can provide companionship in socially isolated situations, for example residents of old people’s homes,’ says Lala. “While ERICA may not be able to hold a long conversation, we think it’s beneficial if people feel they can talk to the robot and that they’re being listened to.” The following applies: the more natural the conversation, the better.
clever trick
The Japanese use a clever trick by having the robot react to someone else’s laugh, says Koen Hindriks, professor at the VU University Amsterdam and not involved in the Japanese study. ‘The robot doesn’t have to understand the content of the conversation, so they skip the difficult part.’
Yet the professor of social robots is not too enthusiastic. ‘The risk of a misplaced smile is great. When people feel that the robot is laughing at them, it can make them want to have nothing to do with the robot anymore.’ In this study, the robot responded at the right time with the right smile 80 percent of the time. ‘Then it goes wrong 1 in 5 times.’ Cultural differences also matter. ‘Giggle is very normal in Japan, in the Netherlands it often comes across as childish.’