A recent study from the University of Toronto says it's "perfectly normal" for people to see facial images in inanimate objects, like Jesus' face in a slice of toast, because human brains are "uniquely wired" to recognize faces.
Researchers at the University of Toronto, in conjunction with several universities in China, used brain-scanning MRI machines and computer-generated images on 20 patients to determine the existence of face pareidolia, a psychological phenomenon of seeing faces in inanimate objects. Common faces detected in inanimate objects include the Man in the Moon, seeing a celebrity resemblance in the curves of a potato chip, or seeing Jesus' face on a slice of toast or in the trunk of a tree.
Kang Lee, a developmental neuroscientist at the University of Toronto who led the recent study, told CBC that face pareidolia happens when two parts of the brain, the frontal cortex and the visual cortex, interact.
Lee said that although many assume that people first recognize an object and then associate it with a face, the function of the brain actually happens in reverse: people determine an image based on pre-existing biases. Lee says this is why highly religious people may use their previous knowledge of religion to detect an image of Jesus or the Virgin Mary in an inanimate object.
"It depends on your personal experience and your personal expectations," Lee said. "So for example, if you are religious and you want to see Jesus, then you're going to see Jesus. If you want to see Mary, you're going to see Mary."
Lee went on to say that many people who claim to see facial images in inanimate objects are ridiculed because such visions seem abnormal.
"But our findings suggest that it's common for people to see non-existent features because human brains are uniquely wired to recognize faces," Lee argued. "So that even when there's only a slight suggestion of facial features, the brain automatically interprets it as a face."
"It's simply a reflection of the tremendous power that our brains have and how it essentially imposes itself on the outside world, rather than the other way around."
The University of Toronto researchers determined their results, which were published in the Cortex journal, by showing different computer-generated images to 20 patients, ages 18 to 25. Half of the patients were told they would be seeing an image showing an alphabetical letter, while the other half was told they would be seeing an image of a face.
The results of the test showed that even though the computer-generated images were random, people claimed to have seen what they wanted to see. Those expecting to see letters said they saw a letter, and those expecting to see faces said they saw a face, even though the images possessed neither.
Lee added to The Daily Mail that the necessity of humans to detect a face in an object may be related to the importance of recognizing faces in social interactions.
"This tendency to detect faces in ambiguous visual information is perhaps highly adaptive given the supreme importance of faces in our social life and the high cost resulting from failure to detect a true face."