text: Third, "The facial expression for each emotion are universal," observes Dr. Huang, " even though individuals often show varying degrees of expressions"(like not smiling as broadly). Using video imagery, the new emotion - recognition software tracks theese facial movements- ina real face or on the painted face of Mona Lisa. By weighting the different units, the software can even identitfy mixed emotions(as in da Vinci's master piece). Each expression is compared against a neutral face (showing no emotion).