In 2004, an online casino bought a toasted cheese sandwich for $28,000 from Diane Duyser, bearing the face of a woman. Duyser said she was taking a bite from the toast when she noticed a face in her toast staring back at her, which is a bit scary.

Duyser's sandwich is just one of the many things when people often see faces in everyday objects, from a surprised bowling ball to a grimacing apple. Some would also claim that they see Jesus on their toast, taco, and pancake or even on a banana peel just as how Dursey saw a woman on hers.

Seeing faces in inanimate objects is called the face pareidolia, a psychological phenomenon that relates to how the human brain is primed. For example, Leonardo da Vinci described seeing characters in natural carvings, which he claims inspired him on his artworks.

A new study by the researchers from UNSW Sydney suggests that the human brain processes the "fake" face the same way it processes the real faces.

Face Pareidolia: The Psychology of Seeing Faces In Inanimate Objects
(Photo: Wikimedia Commons)
Pareidolia of an Indian face in a rock

Why Does Face Pareidolia Occur?

According to Dr. Colin Palmer from UNSW Science's School of Psychology, the lead researcher of the paper published in the journal Psychological Science, face perception is involved in understanding face pareidolia.

The likely reason for seeing a face on objects is that basic features that describe a human face are something that the brain is particularly primed to recognize. But face perception is also recognizing who the person is, and read information from their face, like knowing if they are happy or sad.

Dr. Palmer said that these associations depend on parts of the brain that are specialized to extract this information from what the person sees.

Dr. Palmer and his colleague, Professor Colin Clifford from the UNSW study, examines whether the mechanisms in the brains used in extracting this information in identifying a face when one looks at another is also the same when a person experiences face pareidolia.

They tested this using a visual illusion process wherein a person's perception is influenced by what he has recently or repeatedly seen, called the "sensory adaptation."

They found that repeated exposure to pareidolia faces a specific direction influenced how a person perceives an object. That means the feeling of pareidolia "maybe because the features of the object are activating mechanisms in your brain that are designed to read that kind of information from human faces," the researchers said.

In short, the study suggests that face pareidolia is a visual illusion.

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A Product of Evolution

Studies have shown that face pareidolia has also been observed among monkeys. According to Dr. Palmer, face pareidolia might be a product of human evolution, inherited from the primates.

Human brains have evolved in a way to facilitate social interactions, as recognizing faces is an evolutionary advantage to detect predators. So if a person evolved to be excellent in identifying faces, it may lead to false positives or seeing fake faces.

Their research could help understand cognitive disorders relating to facial recognition like prosopagnosia, the inability to perceive faces, and autism spectrum disorder, in which they could have difficulty processing information from the faces of other people.

Therefore, studies like this aim to understand the difficulties of facial recognition in everyday life.

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