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Mona Lisa’s Smile Isn’t So Ambiguous After All

A new study that utilizes the famous painting finds context influences how we interpret facial expressions.

By Tom Jacobs


(Photo: Wikimedia Commons)

Why is the Mona Lisa among the best-known artworks of all time? One frequently cited reason is the enigmatic quality of her slight smile, which seems to conceal more than it reveals.

Well, a study just published in the journal Scientific Reports suggests her expression isn’t ambiguous at all. It reports that, in two experiments, nearly 100 percent of participants viewed her as happy.

“‘Ambiguity’ along the happy-sad axis of emotional face expressions is not the central feature making (Leonardo) da Vinci’s painting as famous as it is,” writes a German research team led by psychologists Emanuela Liaci and Jurgen Kornmeier of the University of Freiburg.

That somewhat surprising finding emerged from a study that utilized the ubiquitous image to test how we interpret facial expressions. It found context plays a large role in how a specific smile or frown is construed.

For their first experiment, the researchers created eight alternative versions of the Mona Lisa by subtly manipulating the curvature of her mouth. Twelve participants reported whether they perceived each (as well as the original) as either happy or sad, and how certain they were of that judgment.

The researchers report “the original Mona Lisa was always perceived as happy,” as were the manipulated versions in which her smile was turned slightly up.

Interestingly, they also found “the happiest stimulus variant was identified faster and with a higher confidence rate than the saddest,” suggesting we identify happiness more quickly and definitively than sadness.

For the second experiment, the researchers used a different set of nine images, ranging from the most unhappy version of the Mona Lisa to the original. They found images that had been rated as ambiguous in the first experiment were seen by most participants as happy when placed in this new context.

“Perception of, and reaction to, emotional face content is relative,” the researchers conclude.

So don’t be so confident you can read someone’s face and know what they’re feeling: Your interpretation may be biased by the faces you have been exposed to earlier.

As for the Mona Lisa, we’re going to have to consider some of the other possible reasons it became so famous — such as the fact it hung on the wall of Napoleon’s bedroom.