They say the facial expressions for each emotion are universal because even though individuals often show varying degrees of expression, the new emotion are facial movements for example the painted face from the Mona Lisa, we can identify a lot emotions as Vinci's masterpiece. Each expression is a neutral face. Of course, most of us would have trouble actually describing each facial trait that conveys happy,worried,sad,etc.

imaginate if the computer know when your happy or sad, that well be so cool, then you know if someone is sad and you can help him or you can know if this person is happy and he make you happy two, the can be great to create new stuff like videogame tv show and all kinda things, most human comunication is nonverbal, including emotionalcomunication, so that mean the computers have to understand that too, sometimes not only moving your facial muscles make make you express your emotion but that maybe make you feel them,making that can reveal sabout the science of the emotions.