Have you ever opened a bag of chips only to find Santa Claus looking back at you? Or turned a corner to see a smile as wide as a building? Humans often see faces in all kinds of mundane objects, but these faces aren’t real—they’re illusions due to a phenomenon known as face pareidolia. This article explores why exactly this happens and how far this distortion of reality can go.
Humans are social animals, and reading faces is an important part of our ability to understand each other. Even a glimpse of someone’s face can help you determine if you’ve met them before, what mood they’re in, and if they’re paying attention to you. We even use facial features to make snap judgments about a person’s potential trustworthiness or aggression. To capture all this vital information, humans have evolved to be very sensitive to face-like structures.
Whenever we see something, our brain immediately starts working to identify the new visual stimuli based on our expectations and prior knowledge. And since faces are so important, humans have evolved several regions of the brain that enable us to identify them faster than other visual stimuli. Whereas recognizing most objects takes our brain around a quarter of a second, we can detect a face in just a tenth of a second. It makes sense that we’d prioritize identifying faces over everything else.
However, brain imaging studies have revealed that these regions may actually be too sensitive, leading them to find faces where they don’t exist. In one study, participants reported seeing illusory faces in over 35% of pure-noise images shown to them, despite the fact that nothing was there. It might seem concerning that our brains can be so wrong so often, but these illusory faces might actually be a byproduct of something evolutionarily advantageous.
Since processing all the visual input we encounter quickly and correctly is an enormous computational effort for the brain, this kind of hypersensitivity might act as a useful shortcut. After all, seeing illusory faces is usually harmless, while missing a real face can lead to serious issues. But for hypersensitivity to be more helpful than harmful, our brains also need to be quick at determining when a face is real and when it isn’t.
To answer this question, researchers used a form of brain imaging known as magnetoencephalography. By measuring the magnetic fields caused by electric currents in the brain, this technique allows us to track changes in brain activity at the scale of milliseconds. With this tool, researchers revealed that the brain generally recognizes a face as illusory within a quarter of a second—around the same time that we can identify most non-face visual stimuli. However, even after our brain knows the face is fake, we can still see it in the object.
By messing with these brain areas, we can further impact our ability to differentiate between fact from fiction. In one study, researchers stimulated a participant’s fusiform face area while they were looking at a non-face object. As a result, the participant reported momentarily seeing facial features despite the object remaining unchanged. While looking at a real face, stimulation of this same area created perceived distortions of the eyes and nose.
These studies suggest that certain features are crucial to face detection. Just three dots can be enough to represent eyes and a mouth. People will even assign gender, age, and emotion to illusory faces. It’s unclear whether a person’s culture or individual history impacts these perceptions, but we do know that pareidolia isn’t unique to the human experience. Rhesus macaque monkeys show eye movements similar to our own when observing pareidolia-inducing objects and real faces, suggesting that this phenomenon is baked deep into our social primate brains.
So, next time you see an unexpected face in a coffee, car, or cabinet, remember that it’s just your brain working overtime not to miss the faces that really matter.
Create your own face pareidolia art! Gather various objects like leaves, buttons, and sticks. Arrange them on a piece of paper to form a face. Take a picture of your creation and share it with the class. Discuss how our brains can see faces in these random objects.
Test how quickly you can identify faces! Use a set of images that include both real faces and objects with face-like features. Time yourself to see how fast you can correctly identify the real faces. Compare your times with your classmates and discuss why some faces were easier to spot than others.
Go on a nature walk and look for face-like patterns in trees, rocks, and clouds. Take notes or draw the faces you find. Share your findings with the class and discuss why certain objects made you see faces.
Role-play as neuroscientists using brain imaging techniques. One student can pretend to be the researcher, while another pretends to be the participant. Use a simple script to simulate how magnetoencephalography (MEG) might be used to study face pareidolia. Discuss what you learned about how the brain processes faces.
Conduct an experiment to see which features are most important for face detection. Draw simple faces with different combinations of dots and lines (e.g., just eyes, just a mouth, or both). Show these drawings to your classmates and ask them to identify which ones look like faces. Record the results and discuss which features were most crucial for recognizing a face.
pareidolia – the tendency to perceive a specific, often meaningful, image or pattern in a random or ambiguous visual stimulus – Many people experience pareidolia when they see shapes of animals in clouds or faces in inanimate objects.
illusions – misinterpretations or distortions of sensory stimuli that deceive or trick the brain into perceiving something that is not there or misperceiving something that is – Optical illusions can create the perception of movement or make objects appear larger or smaller than they actually are.
faces – the front part of the head, from the forehead to the chin, or the expression on this part, or the expression in someone’s eyes – She had a kind face that made everyone feel welcome.
brain – the organ inside the head that controls thought, memory, feelings, and activity – The brain is composed of billions of neurons that communicate through electrical and chemical signals.
visual stimuli – any form of visual information or input that is received and interpreted by the brain through the eyes – The colorful paintings in the art gallery provided a variety of visual stimuli for the visitors.
hypersensitivity – an excessive or abnormal sensitivity to stimuli, often resulting in heightened reactions or responses – People with allergies may experience hypersensitivity to certain substances, causing severe allergic reactions.
advantage – a favorable or beneficial circumstance or position that gives someone a better chance of success or superiority – Having good communication skills can give you an advantage in job interviews.
shortcut – a quicker or more direct way of reaching a destination, completing a task, or achieving a goal – Taking the highway instead of the local roads is a shortcut to get to the city faster.
perception – the process of recognizing, interpreting, and organizing sensory information received from the environment – Our perception of the world is influenced by our past experiences, beliefs, and cultural background.
features – distinctive attributes or characteristics of a person, place, or thing – The new smartphone boasts advanced features such as facial recognition and a high-resolution camera.
