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