On July 25, 1976, the Viking 1 spacecraft sent back an image from a region on Mars called Cydonia. In the middle of the rocky landscape, something appeared that made the whole world sit up and take notice: a face, almost two kilometers wide, staring up at space. NASA knew it was a natural hill, but the image took on a life of its own for decades. The phenomenon behind that Martian face has a name – pareidolia – and it also explains why a poster featuring a face grabs us in a way few other images do. In this article, we dig into what research actually knows about why the brain sees faces everywhere, and what that means when you choose art for your wall.
Pareidolia is the brain’s tendency to interpret random shapes as something meaningful – and preferably as faces. Two dots and a line are enough. An electrical outlet, the front of a car, a cloud formation, the foam on a cappuccino: suddenly, something is looking back at us. This isn’t imagination in the everyday sense, but a deeply ingrained reflex that researchers in recent years have been able to map down to individual brain regions and milliseconds.
The face on Mars and why a hill could fool the whole world
The story of the Cydonia face is perhaps the most famous case of pareidolia ever. When the Viking 1 probe photographed the area, the light fell at an angle that cast shadows exactly where the eyes, nose, and mouth should be. NASA released the image with a cheeky caption about a giant stone face, and that was that. During the 1980s and 1990s, entire pseudoscientific theories about a lost Martian civilization were built around that very image.
Then came the verdict. When Mars Global Surveyor later photographed the same hill at a much higher resolution, from different angles and in different light, the face disappeared. What remained was an ordinary, weathered plateau hill. The face had never been in the rock – it was in the observer. The same goes for the man in the moon, the old man in the wood grain, and Jesus in toast: the pattern lies in our perception, not in the object.
"The face on Mars was never in the rock. It was in the observer – and the same reflex determines which images stick on your wall."
What makes the story interesting to those of us who love art is that it reveals how quickly and involuntarily the face reflex works. We can’t choose not to see a face. And that very involuntary response is exactly what artists have knowingly exploited for centuries.
What the brain actually does – the face area and the rapid milliseconds
On the underside of the brain, in the temporal lobe, is an area researchers call the fusiform face area. Its sole main function is to recognize faces. For a long time, people thought this area responded only to real faces. Modern research reveals something more surprising: the area also lights up in response to false faces.
A comprehensive study published in the journal PNAS in 2024 had participants look at Arcimboldo’s famous portraits while their brains were imaged. The results showed that the illusory faces activated the same network as real faces—the fusiform face area, the posterior superior temporal sulcus, and the inferior frontal gyrus, all in the right hemisphere. Even more recent research using electrodes placed directly in the brain has confirmed that pareidolic faces are processed by the same neural pathways, and on the same timeline, as real faces.
The timing is the most striking part. The brain decides that something is a face within the first couple of hundred milliseconds—long before you have time to think about it consciously. That means that when your gaze falls on a poster featuring a face, your brain has already reacted before you even register that you’re looking at it. No other kind of image gets this fast track through perception.
Quick facts: In a study by the National Institute of Mental Health, published in PNAS in 2022, participants rated 256 everyday objects containing illusory faces. Although a stone face has no biological sex, the faces were perceived as male in 81.4 percent of cases, compared with 18.6 percent female—a roughly four-to-one imbalance.
Arcimboldo’s fruit heads and the mystery of male faces
No artist has played with pareidolia as systematically as the Italian Giuseppe Arcimboldo (1526–1593). As a court painter to the Habsburgs in Vienna and Prague, he built portraits entirely out of fruit, vegetables, flowers, fish, and books. Up close, you see a basket of pears, grapes, and cabbage. Take a few steps back, and there’s a fully human face, assembled from parts that, individually, have nothing whatsoever to do with faces.
Arcimboldo’s art is a laboratory for the entire phenomenon. He shows that the brain doesn’t build faces piece by piece, like a puzzle, but grasps the whole at once. As soon as the different elements happen to fall into the right arrangement—two things at the top, something in the middle, something horizontal at the bottom—the face reflex kicks in, regardless of what the parts actually represent.
The study mentioned on male faces raises an even deeper question. Why do we interpret a gender-neutral pattern as a man rather than a woman? The researchers suggest that it reveals an ingrained bias in how we read faces from minimal information: our fastest, most automatic interpretation of a face seems to have a male default. It says something about how closely culture and biology are intertwined in the very first moment of perception—a reminder that a poster never encounters a neutral gaze.
From cave walls to modern line portraits
The face motif is probably the oldest in art history, and pareidolia is part of the explanation. Our brain rewards faces with attention, which is why artists throughout history have returned to them. A contemporary minimalist line portrait—just a few flowing strokes suggesting a profile—works for exactly the same reason as Arcimboldo’s fruit heads. You don’t need to see the whole face. The suggestion is enough for the reflex to fill in the rest.
What pareidolia means for the art on your wall
Understanding the face reflex is surprisingly useful when choosing wall art. The first thing to understand is that a face motif almost always draws the eye first. If you hang several photographic artworks together and one of them features a face, it will be what the eye seeks out immediately. This makes face motifs a powerful focal point in a composition—but also something you should place deliberately, not by chance.
The second is that implied faces are often more interesting than clearly defined ones. A minimalist design that merely suggests a profile invites the brain to complete the image itself, and that small mental effort creates a stronger connection to the artwork. It’s the same mechanism that lets us look at an abstract composition for a long time and suddenly make out a face in the shapes. Many abstract posters thrive on precisely this tension between form and recognition.
The third is about the feeling in the room. A face on the wall creates company. Research on pareidolia shows that we don’t just see faces—we also attribute emotions, age, and intent to them in an instant. A friendly, open gaze in a poster featuring faces can therefore make a room feel more alive and less lonely, while a stern or averted expression sets a completely different tone. If you’d rather have calm without gazes, black-and-white landscapes or still lifes are a deliberate counterchoice.
Tip: Try the pareidolia effect at home. Stand five meters from a gallery wall and notice which motif your eye seeks out first. Is it a face, or even a motif that suggests one? If you want that particular artwork to be the room’s obvious focal point, move it to eye level on the most visible section of wall. If you want to tone it down, hang it farther out in the composition.
When faces become too much
The downside of this reflex is that faces demand attention. In a bedroom, where the brain should ideally wind down, several pairs of eyes on the wall can actually keep you a little more alert than you’d like. Nature motifs, soft shapes, or botanical works are often a wiser choice there, while face motifs work best in living rooms, entryways, and home offices, where a little extra alertness is more of an asset.
There’s also the question of how much to use. Hang ten faces close together and they compete for attention, and none becomes a true focal point. A single striking face motif, surrounded by calmer landscapes, geometric designs, or still lifes, has all the more impact precisely because the reflex has only one place to land. The same principle applies to size: one large portrait can carry an entire room on its own, while several small faces are better grouped intentionally than spread across the wall. Think of face motifs as the seasoning in a composition, not its base.
Frequently asked questions about pareidolia and faces in art
The next time you stand in front of a blank wall and choose a motif, remember the face on Mars from 1976. The reflex that tricked an entire world into seeing a creature in a rocky hill is the same reflex that determines which artwork your eyes seek out when you step into your own room. Use it consciously: let a striking face motif become the focal point where you want life and presence, and save calmer motifs for rooms where your brain should be able to rest. If you’d like to read more about how perception shapes our experience of art, we’ve written about why the brain prefers certain art, our attraction to soft lines, and the psychology of color. Feel free to explore our selection of photographic art and portraits and find the face that will look back at you every day.
Sources: PNAS (2024), Dynamic brain communication underwriting face pareidolia; Wardle et al., PNAS (2022), Illusory faces are more likely to be perceived as male than female; Scientific American, The Face on Mars and Other Cases of Cosmic Pareidolia.