text: Much of the human communication is nonverbal which includes emotional communications, so computers need to understand that too. This technology is basically based upon the muscular action units one gives away. In the text states, "They even indicate the difference between a geneuine smile and a forced one. In the real smile, the zygomatic major (muscles that begin at your cheek bones) lift the corners of your mouth. Meanwhile, muscles called orbicularis oculi pars palpabraeus make crow's-feet around your eyes. But in a false smile, the mouth is stretched sude ways using the zygomatic major and and a different muscle, the risorius." They say faces don't lie, so this technology would be able to read even the fake smile you put on.