Leonardo da Vinci’s La Gioconda—the Mona Lisa—holds a special place in the art world, and not just because it is arguably the world’s most famous painting. It also lends its name to a phenomenon well known to fans of both art museums and ghost stories: the “Mona Lisa effect,” or the maddening, fascinating impression that a portrait’s fixed gaze is following you around the room. Even though we know the eyes aren’t moving, the feeling is certainly real.
“Curiously enough, we don’t have to stand right in front of the image in order to have the impression of being looked at—even if the person portrayed in the image looks straight ahead,” said Sebastian Loth, a cognitive scientist at the Cluster of Excellence Cognitive Interaction Technology (CITEC) at Bielefeld University in Germany in a release. “This impression emerges if we stand to the left or right and at different distances from the image. The robust sensation of ‘being looked at’ is precisely the Mona Lisa effect.”
But, according to a new study by Loth and his colleague Gernot Horstmann, and published in the journal i-Perception, Mona Lisa herself just isn’t that into you.
The Mona Lisa effect is a centuries-old optical illusion that relies on tricky interplay of light and shadow, which shifts our perspective of the subject’s stare. Since canvases are flat, the depth of a painting cannot change, but it can look like it does. This is why some people insist that Mona Lisa’s gaze can look like a skeptical side-eye from one side and a thoughtful glance straight-on. But, according to the new research, the painting that lends the phenomenon its name doesn’t actually display it. “The effect itself is undeniable and demonstrable,” Loth said. “But with the Mona Lisa, of all paintings, we didn’t get this impression.”
Horstmann and Loth enlisted 24 study subjects to look at an image of the Mona Lisa on a computer screen and try to decide where she is looking. “Our perception is influenced by our beliefs to quite some extent,” Loth said in an interview. Our judgment of things like Mona Lisa’s gaze is inherently flawed, so the research team “could not just go and ask our participants about their impression.” So he and Horstmann had participants determine where her gaze fell on a small folding ruler. The researchers put the ruler varying distances from the monitor, and also used 15 different zoom levels (some participants saw her entire head, some only her eyes) so the rest of her facial features wouldn’t influence the perception of her gaze.
Horstmann and Loth collected more than 2,000 assessments, and determined that the Mona Lisa is never looking directly at you at all, but slightly to the right. “More specifically, the gaze angle was 15.4 degrees on average,” Horstmann said in the release. “Thus, it is clear that the term ‘Mona Lisa Effect’ is nothing but a misnomer.” It says more about the viewer, actually. “It illustrates the strong desire to be looked at and to be someone else’s center of attention—to be relevant to someone, even if you don’t know the person at all.”