"We have data that happy drivers' accident rates are drastically lower than depressed ones, so this robot stays there to make sure the driver is happy always," said Masato Inoue, chief designer at Nissan's exploratory design group, in an interview at the Motor Show. "This guides the driver and sometimes cheers up the driver. For example, if the driver is irritated it might say 'Hey, you look somehow angry. Why? Please calm down.'"
It doesn't take a robot to do this. The same function could be accomplished by cameras mounted in the car's dashboard, but Inoue said there's a conscious choice behind the robot.