Is Mona Lisa Smiling or Smirking?
And what’s she hiding? Either way, something’s not right.
When some climate activists threw soup at the Mona Lisa the other day, it was hard to tell through the protective glass at the Louvre if the iconic face was smiling or smirking. In fact, it’s always been hard to tell.
Five centuries after Leonardo da Vinci created the world’s most famous painting, Mona Lisa continues to transfix art lovers and just about anyone who glances at gaze that always seem to be gazing right back, no matter what angle you view from.
That includes scientists, who, like many people, have wondered if the subject in the painting has cracked a modest grin or not.
Back in 2017, researchers concluded the arresting, complex smirk is, in fact, a smile. But then in 2019 some other scientists argued that the lopsided expression is clearly hiding something.
If you look close, you can see the evidence:
The mouth of the subject in the Mona Lisa (which is the name of the painting, by the way, not the painted) turns up slightly on the left side — an apparent sign of happiness, both research groups agree. But the right side curves down ever so slightly, suggesting something else.
So in the 2019 study, published in the journal Cortex, scientists mixed some art and science and made two doctored images of the painting by first copying and flipping the left half of the subject’s smile over to the right side to make both sides upturned. They did the opposite to create a doctored image of the other look.
Then they showed the two images to 42 people.
Almost all of the people — 39 — saw the upturned lips as a sign of happiness. None of them thought the other version exhibited happiness, and 35 rated it neutral, while five perceived it as disgust and two called it sadness.
The scientists now say the real image does involve a smile, but it isn’t genuine.
“Asymmetric smiles are an expression of lies,” says the study’s lead author, Luca Marsili, a neurologist at the University of Cincinnati. That idea is based on the neuropsychology of emotions, Marsili explains, developed over many years and explained in psychologist Paul Ekman’s book Telling Lies.
Marsili and his colleagues, Lucia Ricciardi at St. George’s University of London and Matteo Bologna at the Sapienza University of Rome, also note that the subject in the painting shows no muscle activation in the upper part of the face, whereas a genuine smile is nearly impossible to make without some uplifting of the cheeks and creasing around the eyes (try it).
Questioning the nature of the smile
In 2017, a separate group of researchers used similar Photoshop techniques to create eight variations on the expression, with the corners of the mouth raised or lowered to varying degrees, then had people rank their perceptions of happiness or sadness in each.
The original and all the other positive versions were perceived as happy in nearly every case, and people identified the happy faces quicker and with more certainty than the sad faces.
“It appears as if our brain is biased to positive facial expressions,” said Emanuela Liaci, a researcher at the University of Freiburg in Germany and lead author of the study, which is detailed in the journal Scientific Report.
“We were very surprised to find out that the original Mona Lisa is almost always seen as being happy,” said Liaci’s colleague and professor, Jürgen Kornmeier. “That calls the common opinion among art historians into question.”
When all these competing interpretations were being pondered, I asked Kornmeier what he thought of the study led by Marsili. He called it interesting but said he had some doubts about the conclusions.
“The experiment clearly shows Mona Lisa’s mouth asymmetry,” Kornmeier said. “However, this asymmetry can result from the two-dimensional projection of a three-dimensional face, where the face [is] presented in some deviating angle from [the] front view, which also changed the face illumination. This means that da Vinci’s model could well have had a symmetric smile, despite the asymmetry in the resulting painting.”
Marsili, on the other hand, said the two studies are compatible.
“They concluded that Mona Lisa was smiling,” Marsili told me. “And we agree with that… However, the real nature of her smile is the true question.”
Why was Marsili’s team eager to figure all this out? They study the neurophysiology of movement, including emotion expression and emotion recognition in people with Parkinson’s disease, and how expressions could be a marker for disease prognosis, even in early phases.
“Emotion expression is a link between the ‘organic’ brain and the ‘psychology’ of our mind,” Marsili said. “So fascinating!”
And now the big question
Why might the person in this ancient work of wonder be lying? “Nobody knows,” Marsili said, “but there are many hypotheses.”
Perhaps the subject of the painting had hypothyroidism, as evinced by “thinning hair, yellow skin, and possible goiter,” said Mandeep Mehra, medical director of the Heart & Vascular Center at Brigham and Women’s Hospital, who detailed his interpretation last year in the journal Mayo Clinic Proceedings. Other medical researchers have cited skin lesions and hand swellings to suggest she suffered heart disease or Bell’s palsy. There’s also speculation that Mona Lisa is a portrait of da Vinci’s gay lover, or that it’s actually a self-portrait of the artist in drag.
The simplest explanation? After being told to sit still and smile for hours, the model wasn’t enjoying herself, Marsili and his team figure.
Or maybe da Vinci knowingly crafted the cryptic expression simply to vex us for all time.
Thanks for your support, which makes my reporting and writing possible. To make your days better, check out my book: Make Sleep Your Superpower. And if you’re a writer, sign up for my Writer’s Guide newsletter. Note: Portions of this article were published previously.