A computer has been used to decipher the enigmatic smile of Leonardo da Vinci's Mona Lisa, concluding that she was mainly happy.
Leonardo da Vinci's Mona Lisa was 83 % happy, 9 % disgusted, 6% fearful and 2% angry, a test executed by a University of Amsterdam computer using "emotion recognition" software showed.
The computer rated features such as the curvature of the lips and crinkles around the eyes.
The program, developed with researchers at the University of Illinois, draws on a database of young female faces to derive an average "neutral" expression.
The software uses this average expression as the standard for comparisons, Sofia News Agency reports.