Your eyes’ critical role in Mona Lisa’s famous smile
My first-grader didn’t know the Mona Lisa by name, but she recognized a picture of it. Painted around 1503, the Mona Lisa has bewitched viewers in a way it’s subject, Lisa del Giocondo, could only dream of. That’s not a knock against del Giocondo, but more an acknowledgement of Leonardo da Vinci’s masterful control over the image. The famous smile teases your gaze, partly because da Vinci cheated.
Smiling unless you stare
The smile in Mona Lisa has been dissected repeatedly: the sitter’s face appears to have a smile when looking at her eyes, but close examination of the mouth yields a much more slight expression. In fact, looking at other parts of the face seems to bring out more of a grin, until you look back and the smile flattens. The painting becomes exciting, and feels alive, almost like del Giocondo is flirting with you. It’s all made possible by the da Vinci’s control and understanding of our perception.
It’s unlikely that da Vinci understood the neurology of our vision, but he could have been aware of how it played out on a practical level. Our gaze is constantly shifting around, as the center of our field of vision is able to pick up higher-resolution detail than our peripheral vision. When you focus on the lips, you see the hard details there. But when you look at the eyes, or the hair, or the background, your periphery blurs the lips and cheeks into more of a smile shape. The balance is delicate, but it becomes more obvious in lower quality reproductions of the painting, such as a photocopy, where the shadows around the mouth blur together and overemphasize the smile.
Iterating on interactive portraits
So was da Vinci just lucking out with this smile? Did he know what delicate effect he was creating? Another portrait, La Bella Principessa, was recently confirmed to be by da Vinci, and it demonstrates the focus/periphery smile as well. The fact that La Bella Principessa predates the Mona Lisa suggests that this was a specific effort on the painter’s part. 500 years later, it seems we’re still enjoying da Vinci’s efforts in creating these subtly interactive paintings.
Source: A Second da Vinci Smile Has Been Discovered by Stephen L. Macknik, Illusion Chasers