Zoo Station

Hello, World!

For my first post in this forum I wanted to write about something from my field, Computer Science, that would have as universal an appeal as I could imagine while completely avoiding anything political or current. I think I have come up with the perfect topic: the role of CS in explaining the appeal of Mona Lisa, arguably the most famous painting ever.

If you had to name the one most striking feature of the painting, it would surely be Mona Lisa's smile. What is it about the painting that makes her smile so striking and, well, enigmatic? We're starting to see some serious scientific inquiry into this and already learning interesting things about the painting and, more importantly, about human visual perception in the process.

Christopher Tyler and Leonid Kontsevich at the Smith-Kettlewell Eye Research Institute note that adding slight noise over the mouth region can dramatically change our perception of Mona Lisa's expression; their paper gives the details. The New Scientist has a nice little article about their work in which they note:

Tyler says our visual system contains many sources of noise: fluctuations in the number of photons hitting light-receiving cells in the eye, spontaneous false activation of photon absorbing pigments, and randomness in the firing of neurons that carry the visual signals to the brain. Tyler thinks this natural noise makes people observing the picture believe its expression is subtly changing, rather than thinking they are seeing a single ambiguous expression.

Following a different line of work, neurobiologist Margaret Livingstone of the Harvard Medical School argues that the smile is so enigmatic because it is perceived differently when viewed foveally as opposed to peripherally.

So when you look at her eyes or the background, you see a smile like the one on the left, or in the middle, and you think she is smiling. But when you look directly at her mouth, it looks more like the panel on the right, and her smile seems to vanish. The fact that the degree of her smile varies so much with gaze angle makes her expression dynamic, and the fact that her smile vanishes when you look directly at it, makes it seem elusive.

You can hear Livingstone talk about this theory in this NPR story.

Is the mystery of Mona Lisa's smile now revealed? I would like to believe that further scientific inquiry will lead to still more insights. We shall wait and see. Meanwhile, if any of you is going to be visiting the Louvre soon, you have just been given some new things to think about as you stare at the great painting.