The Man in the Moon isn’t just actress Reese Witherspoon’s breakout role in a movie that leaves us in a fit of sobs by the end — it’s an actual premise in which people believe they can see a face in the moon or other inanimate objects. Scientists classify this as face pareidolia, “the illusory perception of non-existent faces.” And after looking into society's current obsession with faces, National Geographic came across a study that found the part of the brain responsible for this illusion.

“Most people think you have to be mentally abnormal to see these types of images, so individuals reporting this phenomenon are often ridiculed," said Kang Lee, lead study author and professor of the University of Toronto's Eric Jackman Institute of Child Study, in a press release. "But our findings suggest that it's common for people to see non-existent features because human brains are uniquely wired to recognize faces, so that even when there's only a slight suggestion of facial features the brain automatically interprets it as a face.” These findings were published in the journal Cortex.

Lee and his team presented 20 volunteers with pure-noise images, or squares of black, white, and gray blobs while inside a brain scanner. They told volunteers half of the images contained hard-to-detect faces or letters; if volunteers spotted a face, they pressed a button. While participants reported seeing faces or letters up to 38 percent of the time, the images didn’t actually have any faces or letters. Yep, the researchers tricked them.

Since participants were inside a brain scanner, researchers could see that the right fusiform face area (rFFA) showed a specific response when participants “saw” faces as opposed to letters in the images. Researchers wrote that this suggests the rFFA plays a specific role not only in processing of real faces but also in illusory face perception." Furthermore, it would appear that human face processing has a "strong top-down component" in which the slightest expectaction of seeing a face or letter can, in fact, make one appear.

In other words, people’s expectations influence the faces, words, or letters they see in an inanimate object. These expectations activate different parts of the brain that process images. It's the first study to analyze brain scans and behavioral responses regarding face pareidolia. Instead of an anomaly or imagination, researchers found evidence the brain’s frontal cortex and posterior visual cortex are at work rather than some kind of anomaly or pure imagination.

Researchers concluded the frontal cortex “helps generate expectations and sends signals to the visual cortex to enhance the interpretation stimuli from the outside world.” It’s a normal response, suggesting “seeing is believing” should be “believing is seeing.”

Source: Liu J, et al. Seeing Jesus in toast: Neural and behavioral correlates of face pareidolia. Cortex. 2014.