Jesus Christ on toast? Brain scan explains how facial pareidolia forms

One afternoon in 1994, Diana Duyser, a jewelry designer from Florida, United States, experienced an epiphany in her kitchen. Her message came to him through a grilled cheese sandwich. “I went to take a bite, and then I saw this lady looking at me,” she told the

Chicago Tribune

newspaper . The burns on the surface of the bread drew a recognizable silhouette. “It was the Virgin Mary. “I was in

shock

,” she said then. Instead of finishing her snack, Duyser put it in a plastic bag and told her story to the press, first local, then national, and over the years, international. A decade later, with the uncorrupted sandwich becoming a pop icon, she put it up for auction on eBay, where she sold it for $28,000. The sale made it abundantly clear that Ms. Duyser was a marketing genius, but also that she was not the only one to see a human (or divine) face on a slice of bread.

This is what happened not so long ago, when hermitages were built, relics were sold or stories of ghosts or aliens were told. But in recent years, science has begun to understand the complicated neural process by which humans believe we see faces everywhere. It is called facial pareidolia and a few days ago, research published in the journal

PNAS

analyzed how and where it occurs in the brain. Its study can open the door to understanding autism spectrum disorders, schizophrenia or Parkinson's.

“This work uses an electroencephalogram and is in line with recent research,” explains neuropsychologist Saul Martínez-Horta in a telephone conversation. "For some time now, with the ability we have to segment in milliseconds what, when and where activity occurs in our brain, we are beginning to understand the entire sequence of processes that accompanies perception."

In the case of pareidolia, the sequence would be as follows: when we see a human face, or something that vaguely resembles it, “a dialogue” occurs in our brain between different areas. On the one hand, there are the areas that deal with visual stimuli. On the other hand, the areas of memory, which fill in the gaps of what we are seeing with what “we are probably seeing.” And finally, an area called the facial fusiform gyrus that plays a critical role in the earliest stages of recognizing faces, but not any other visual stimulus. “That is, faces begin to be processed in a different area of ​​the brain and they also begin to be processed earlier,” says Martínez-Horta.

How to recognize Elvis

Human perception is not explained as if we were constantly analyzing the external world. What we see about the world is usually an anticipation, we perceive what seems most likely to the brain. “When you see Elvis, you are not recognizing all the elements that make up Elvis's face, but your brain already has a typical representation of his face, it knows it,” says the expert. This way you avoid investing a huge amount of resources reading all the information that comes to you. “The brain accesses memory stores in which we store pieces, fragments, that resemble what we are seeing. And at this point, something is already starting to tell your visual system, hey, this could be Elvis.”

But what happens when we see Elvis on a French fry? The dialogue that occurs between different areas of our brain sometimes works like the game of telephone and sends erroneous information to our heads. There is no face, but we believe we see it. “The fact that pareidolia happens, especially with faces that we know very well, is explained because we store their meaning in memory,” explains Martínez-Horta. And because, in some way, we are programmed to see human faces. We are obsessed with them.

Susana Martínez-Conde, a neurologist at the State University of New York, measures this obsession in her laboratory. “We analyze eye movements, exposing participants to all types of images, and we see that we spend much more time examining faces than other objects,” she confirms in a telephone conversation. This, at an evolutionary level, makes sense, "because being social animals, it is important to recognize if the face we are seeing is that of a friend, a family member, an enemy or a neighbor with whom we have fought." In fact, it is a common trait with other social mammals, such as monkeys, which also suffer from pareidolia.

Pareidolias say more about what we see than what we see. Our way of understanding the world is reflected in optical illusions. And this is an overwhelmingly masculine way. In a study published by the journal

PNAS

,

it was found that 80% of the participants had a male bias when giving a gender to faces. On toast, on potatoes or on walls, we see men's faces everywhere. There is a tendency to perceive illusory faces as masculine rather than feminine, by a ratio of four to one. Only 3% of participants had a female bias.

This hallucination reflects the brain's broader tendency to find meaning where there is none. “To organize disordered components into a coherent perception, artificially. Because it is not a phenomenon that exists in the world, but rather we construct it, so that our subjective perception does not correspond to objective reality,” says Martínez-Conde.

The same thing happens with sounds, when we believe that someone has said our name. Or with psychophonies or hidden messages in audio tracks. “The information is disorganized, but since we are wired to recognize words and give them meaning, we tend to find words where there are none,” explains the expert. Perception is more construction and simulation than exact reconstruction of reality.

But after perceiving this supposed face, our brain reevaluates what we are seeing. Unless religious or esoteric beliefs come into play, we understand that it is a hallucination or an optical illusion. As long as there is no type of illness. “We study the phenomenon of pareidolia a lot in the context of neurodegenerative diseases, especially Parkinson's,” explains Martínez-Horta. A 2021 study claimed that more than 47% of Parkinson's patients had experienced this type of optical illusion. “Before patients have more complex and grotesque hallucinations, they begin to see faces everywhere,” confirms the expert. But this subsequent process of understanding does not occur here, so pareidolia is integrated as part of reality.

Understanding this phenomenon can help to better understand neurodegenerative diseases, and explain how humans perceive the world around us. Having located the part of the brain responsible for this phenomenon not only confirms that the toast is not Jesus Christ, but it can help us understand ourselves better. “Pareidolia tells us very well,” summarizes Martínez-Horta. “The fact that we have no control over what we are seeing is an example of how we often perceive the world.”