This guy made a little robot that mimics his expressions
"The purpose of my research and development is not to answer the philosophical theme 'Will a robot (or computer) obtain a mind or emotions like mankind,'" says Japanese artist Takayuki Todo, "but to portray the sense of conscious emotion such as a human can produce. I think it is possible to represent human-like communications by constructing an adequate interaction system between facial sensing and expressions."
To test out his ideas, Takayuki made a small plastic head with simplified static facial features, realistic eyes that can rotate, and articulated eyebrows. The head can move around on the neck. When Takayuki makes different facial expressions in front of a webcam, the robot copies them. It's interesting to see how well the robot's expressions match Takayuki's, even though it can only tilt and turn its head, roll its eyes, and move its eyebrows. In other words, the mouth doesn't seem to matter much in expressions. The head seems very lifelike, much more so than those scary robots that pull back their rubber mouth skin to expose a row of teeth.
Image: YouTube screengrab