Whether in a cloud, the front of a car, or a $28,000 toasted sandwich supposedly resembling the Virgin Mary, seeing faces in inanimate objects is a common experience.
According to new research by the University of Sydney, our brains detect and respond emotionally to these illusory faces the same way they do to real human faces.
Face pareidolia – seeing faces in random objects or patterns of light and shadow – is an everyday phenomenon. Once considered a symptom of psychosis, it arises from an error in visual perception.
Lead researcher Prof David Alais, of the University of Sydney, said human brains are evolutionarily hardwired to recognise faces, with highly specialised brain regions for facial detection and processing.
“We are such a sophisticated social species and face recognition is very important,” Alais said. “You need to recognise who it is, is it family, is it a friend or foe, what are their intentions and emotions?
“Faces are detected incredibly fast. The brain seems to do this… using a kind of template-matching procedure, so if it sees an object that appears to have two eyes above a nose above a mouth, then it goes, ‘Oh I’m seeing a face.’
“It’s a bit fast and loose and sometimes it makes mistakes, so something that resembles a face will often trigger this template match.”
The researchers showed people a sequence of faces – a jumble of both real faces and pareidolia images – and had participants rate each facial expression on a scale between angry and happy.
The researchers found that inanimate objects had a similar emotional priming effect to real faces.
Photograph: PhotoAlto/Laurence Mouton/Getty Images
“What we found was that actually these pareidolia images are processed by the same mechanism that would normally process emotion in a real face,” Alais said.
“You are somehow unable to totally turn off that face response and emotion response and see it as an object. It remains simultaneously an object and a face.”
The study may help to inform research in artificial intelligence or disorders of facial processing such as prosopagnosia, he said.
Earlier research co-authored by Alais showed that in judging a series of faces, the perception of a person’s appearance was biased by the preceding image shown. “If the previous one was attractive, they rated the current one more attractively,” Alais said.
“This also happens with expression,” he said. “If you see a happy face previously, the next face will be rated slightly happier.”
The latest study was published in the peer-reviewed journal Proceedings of the Royal Society B.
