Emotion-mapped Robotic Facial Expressions based on Philosophical Theories of Vagueness

As the field of robotics matures robots will need some method of displaying and modeling emotions. One way of doing this is to use a human-like face on which the robot can make facial expressions corresponding to its emotional state. Yet the connection between a robot’s emotional state and its physical facial expression is not an obvious one: while a smile can gradually increase or decrease in size, there is no principled method of using boolean logic to map changes in facial expressions to changes in emotional states. We give a philosophical analysis of the problem and show that it is rooted in the vagueness of robot emotions. We then outline several methods that have been used in the philosophical literature to model vagueness and propose an experiment that uses our humanoid robot head to determine which philosophical theory is best suited to the task.