IT’S official: Leonardo da Vinci’s Mona Lisa was 83 per cent happy, 9 per cent disgusted, 6 per cent fearful and 2 per cent angry.

Nicu Sebe at the University of Amsterdam in the Netherlands tested emotion-recognition software on the famous enigmatic smile. His algorithm, developed with researchers at the Beckman Institute at the University of Illinois, Urbana-Champaign, examines key facial features such as the curvature of the lips and crinkles around the eyes, then scores each face with respect to six basic emotions. Sebe drew on a database of young female faces to derive an average “neutral” expression, which the software used as a standard to compare the painting against.

Dr Cynthia McVey, a psychologist at Glasgow Caledonian University, tried to explain the apparent conflict in the emotions they found in the Mona Lisa’s face.

“She could have been chuffed he wanted to paint her and … a wee bit disgusted by the old man doing the painting. He might have been in the nude or have come on to her for all we know,” she said. “Or maybe she was annoyed because she had been sitting there for ages and he’s still not finished.”