The ability to see a face in a cloud or a tree is an ancient property of the human brain. According to scientists, it was important for our ancestors not only to see a face, albeit an imaginary one, but also to quickly understand whether it is a friend or foe.
To see the features of a human face in a cloud, on the hood of a bus, in freshly made toast or coffee grounds - all people sometimes have to deal with this effect, which is scientifically called pareidolia.
Pareidolia is a visual illusion in which people see faces, human figures or animals where they are not present: in objects, clouds, starry sky, wallpaper patterns, etc. One of the most famous examples of pareidolia is the famous "face" on Mars.
Scientists from the University of Sydney (Australia) launched a research to understand the evolutionary roots of this phenomenon and explain why a person needs to see funny or threatening faces where they don't exist in reality. They came to the conclusion that pareidolia is part of the survival mechanisms that have long been formed in the human brain, which helped us at the dawn of civilization to quickly determine whether an enemy or a friend is in front of us, regardless of whether it is real or not.
"From an evolutionary point of view, the ability not to miss a single face seems to be far more important than the mistake in which immovable objects are perceived as faces," explained Professor David Alais, author of a study published in the journal Proceedings of the Royal Society. Noticing faces quickly is an immense benefit. However, the system does not work reliably, stupidly applying a two-eye over a nose and lips pattern. This pattern can be matched by many objects, thus causing triggers on faces."
According to scientists, such a trigger in the brain occurs in a few hundredths of a millisecond.
The task of the study was to understand how the human brain works when it encounters the effect of pareidolia: it tries to define its "emotions" or immediately discards it when realizing that it was unreal. It turned out that as soon as the seen face is imprinted in the brain, it immediately begins to analyze its expression in the same way as it does with real faces.
The study involved 17 volunteering university students. Each of them was shown a computer mix of color photographs of real faces and objects that resembled faces.
Each picture was shown very quickly (250 milliseconds), and the participant had to rate the facial expression on a scale of joy to anger, matching it to one of four categories.
It turned out that the processes of ranking real and imaginary persons differ little and people easily match them to a certain level of joy or aggression.
"We found that in reality these images of pareidolia are processed by the same mechanism that is usually triggered when the emotions of a real face are perceived," Ale explained. "For some reason, we are not able to completely turn off the perception of faces and emotions and perceive them as an object. For us, it remains both a face and an object. "
In the course of the study, scientists came to the conclusion that the capability to see faces in natural objects is associated with the fact that people are deeply social creatures, and it is not enough for us to just see a face, it is important for us to understand its emotional state.
"We need to read the facial expression and identify its mood. Is it a friend or foe? Is it joyful, sad, angry, or is it expressing pain?" - said Ale.
Mentally healthy people, as a rule, understand that they are faced with a play of the imagination, whereas patients with mental disorders often mistake pareidolia for reality. According to scientists, research in the future can be used in the treatment of propagnosia, a disorder of facial perception, in which the ability to recognize faces is lost.
In his revious research, Ale showed that in the process of sequential perception of human faces, the volunteer's assessment of emotions is influenced by the assessment of the emotions of the previous picture. "If the previous picture was attractive, they rate the current one more attractive," he said.
In 2014, Canadian scientists, using the method of functional magnetic resonance imaging, found out the neurophysiological nature of pareidolia. It is based on the simultaneous activation of the frontal cortex, which is responsible for expectations, and the part of the visual cortex, which specializes in recognizing faces. This proves that the frontal cortex controls the visual cortex to a large extent. Consciousness controls vision: people expect to see something familiar and they see it.