Why Your Mind Can See Faces Where They Don't Exist

Cookie Monster is an especially common illusion

Posted Feb 10, 2021 | Reviewed by Gary Drevitch

Mike Bowers/Facebook
A hand holds two halves of a geode that bear a striking resemblance to the face of the Sesame Street character Cookie Monster.
Source: Mike Bowers/Facebook

A geode that bears a striking resemblance to a beloved Sesame Street character has taken the internet by storm. What’s truly amazing, though, isn’t what happened to the rock to make it look like Cookie Monster, it’s what happens in our minds to make us think it looks like Cookie Monster.

The experience of recognizing a familiar image in an unrelated object is called pareidolia (pronounced par-eye-DOH-lee-ah), from the Greek para- meaning “abnormal” and eidolon meaning “image." Examples of pareidolia include finding shapes in the clouds, seeing a rabbit in the moon, and interpreting a colon next to a bracket as a smiling face. :)

Pareidolia is a mistake of the mind, part of a human tendency to perceive patterns in random circumstances. Face pareidolia – spotting faces in objects that have none – is its most common form and the one behind our enjoyment of the Cookie Monster geode.

What Causes Pareidolia?

Our brains are hardwired to find and remember patterns.

This knack for pattern recognition isn’t a luxury: it’s essential to our survival. Without it, we would be incapable of the most basic functions, from sorting out all the different sensations that pummel our nervous systems to creating mental maps, avoiding hazards, and identifying foods.

Pattern recognition also allows for our higher-order abilities like reasoning, speaking, decision-making, and problem-solving, to the point that some neuroscientists believe superior pattern processing is the feature that most distinguishes human brains from the brains of other animals.

Joel Muniz/Unsplash
A group of women walk down an alley smiling at the camera.
Source: Joel Muniz/Unsplash

Face detection, in particular, is a human specialty. Two regions of the human brain – the fusiform face area and the occipital face area – are devoted to it, and many other parts of the brain pitch in.

Evolution has dedicated so much of our neural wiring to identifying faces because humans are such social animals. We rely on the people around us for protection, information, and collaboration, so it benefits us to be able to recognize quickly whether someone is a friend or a foe.

Having such a dialed-up facial recognition system, though, comes with drawbacks. We have whole swaths of neurons just waiting for the opportunity to identify a face, any face. Sometimes they misfire, activating when there are no real faces present.

These misidentifications happen in the blink of an eye – just 170 ms – and we have no conscious control over them. That’s why it’s so difficult to “un-see” the illusion of a face even if we know it’s only an accident of light and shadow.

Cookie Monsters Everywhere

With pareidolia, the same faces tend to pop up time and again. Search the web, and you’ll find that spotting Cookie Monster in a random assortment of objects is a pretty common occurrence. Why is that?

Although we’re born with the neurological framework for pattern recognition, it has to be filled in by experience. Take facial recognition: A blind person who gains sight late in life has the necessary brain regions for face detection but still needs a few weeks of real-world seeing before they can begin to identify human faces and tell people apart.

The specific patterns we spot in our environment are further shaped by our culture and background. When we experience face pareidolia, we’re often matching the shapes that we’re seeing with mental templates of faces we’re already familiar with. For a pious Catholic, that might be a bearded Jesus or a veiled Virgin Mary. For a North American child of the ‘70s, ‘80s, or ‘90s, on the other hand, it might be a fuzzy blue Muppet.

We may be prone to spotting Cookie Monster’s face “in the wild” because it’s so simple and has a very recognizable color scheme. In the examples posted online, two round, whitish circles over either a blue area or an oblong shape with a wide, dark space in the middle seems to ring our minds' Cookie Monster alarm bells.

Have a look at the images below for more examples of Cookie Monster pareidolia.

Two paper towel rolls on a blue shelf:

the-hang-man/Reddit
Source: the-hang-man/Reddit

 White rolls and blue packages on a flatbed truck:

TheSpacePope17/Reddit
Source: TheSpacePope17/Reddit

Two round markers over a wide drainage opening on a river:

emileif/Reddit
Source: emileif/Reddit

Ice and snow on a forest stream:

spacejockey8/Reddit
Source: spacejockey8/Reddit

Pasta cooking in a pot with a round pattern formed by bubbles:

Kevlar Yarmulke/Reddit
Source: Kevlar Yarmulke/Reddit

The recent viral sensation isn't even the first geode that's been compared to Cookie Monster:

aruffone/Reddit
A blue geode with two round markings resembling googly eyes and a wide opening resembling a grinning mouth.
Source: aruffone/Reddit