Jurgen Kornmeier, University of Freiburg – Is The Mona Lisa Smiling?

We can all picture the Mona Lisa smile.

Jürgen Kornmeier, senior researcher at the University of Freiburg, looks into whether she’s smiling after all.

Is The Mona Lisa Smiling?



Leonardo da Vinci’s famous portrait of Mona Lisa has been the most discussed

artwork ever. Particular interest has been given to Mona Lisa’s enigmatic

expression: is she happy or sad?

We found that she is

unequivocally happy. We created eight Mona Lisa variants, that differed only in

gradual changes to the curvature of her mouth. Then, we presented the original,

four versions with a sadder face and four with a happier face in random order.

The participants first indicated for each variant whether Mona Lisa’s emotional

face expression was happy or sad by pressing different keys and then rated how

certain they were of their response. The responses were used to calculate a

percentage on a scale from sad to happy and a rating for the certainty of the


The original and all of the more positive versions were perceived as happy in

nearly 100 percent of the cases. The participants identified happy faces more

quickly and with a higher degree of certainty than sad faces.

In a second experiment, we kept the image with the least mouth curvature as the

saddest version, took the original Mona Lisa as the happiest version, and chose

seven intermediate versions, three of them from the first experiment.

Surprisingly, the same participants now changed their perceptual judgment: the

variants, already seen in the previous experiment, were now perceived as overall

‘happier’. Our results indicate that our scale of happiness is not absolute but

adapts to the environment with astonishing speed.

The study is part of a larger project

on how healthy people disambiguate ambiguous visual input during

perception and whether this process is different in people with autism and

psychotic disorder.