 Dina Goldin, Adjunct Professor at Brown University, has argued that the secret is in the dynamic position of "Mona Lisa's" facial muscles, where our mind's eye unconsciously extends her smile; the result is an unusual dynamicity to the face that invokes subtle yet strong emotions in the viewer of the painting.In late 2005, Dutch researchers from the University of Amsterdam ran the painting's image through "emotion recognition" computer software developed in collaboration with the University of Illinois at Urbana-Champaign.The technology demonstration found the smile to be 83% happy, 9% disgusted, 6% fearful, 2% angry, less than 1% neutral, and 0% surprised.