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We Asked a Scientist Why People Keep Seeing Aliens in the Pictures from the Mars Rover

This phenomenon, in which the brain recognises objects in a field of visual noise, is called pareidolia.
Image via NASA

In August 2012, NASA landed a plucky little space robot named Curiosity on Mars.The little guy has been beaming back high definition pictures of the Martial landscape ever since. This is cool as hell. I never want to go to Mars, or space in general, but the eight-year-old in me is still fucking amped that Wall-E's great great great great grandfather is sending us vacation shots from another planet. But that's not enough for some people—they want aliens. CNN has a good summary of all the stuff reportedly seen in the photos: crabs, iguanas and, of course, a crashed UFO.


This phenomenon, in which the brain recognizes objects in a field of visual noise, is called pareidolia. Neuroscientist Joel Voss published a paper on the topic a couple years back titled "The Potato Chip Really Does Look Like Elvis! Neural Hallmarks of Conceptual Processing Associated with Finding Novel Shapes Subjectively Meaningful." Dr. Voss doesn't specialize in visual processing (he mostly researches how to treat memory problems using brain stimulation) but he found evidence that the brain isn't very skeptical when processing what it sees. Instead, it goes for the path of least resistance when presented with visual cues, and actively tries to recognize familiar shapes. This explains why we see Jesus in our food, Elvis in our chips, and floating spoons in our Mars Rover photographs.

We talked about his research, how the brain processes visual input and the nature of reality. (I did not ask him how mirrors can be real if our eyes aren't real.)

VICE: Can you briefly explain the Potato Chip Elvis phenomenon?
Joel Voss: Imagine you look at a picture of a potted plant. Some parts of your visual system have to do work to process the features of the plant. They pick apart its shapes and eventually categorize it and recognize it. That involves the interaction of a bunch of neurons that do the specific operations for identifying that potted plant. Because they work together in doing that, when you see the plant the second time around, these neurons don't have to do as much work. They've been co-active recently and that facilitates further co-action. As a result, there's not as much activity [in your brain] when you see [the same potted plant] again soon after.


What we did was show a whole mess of random squiggles to a person, and they would tell us whether they found meaning in the squiggle or not—yes, yes, no. After a delay, they see the same squiggles again in a different, randomized order, and they'd tell us again whether they think the squiggles look like anything.

The brain treats these random squiggly things like meaningful objects if the subjects report they are meaningful, but they don't do that if they say they are meaningless.

UFO SIGHTINGS DAILY: Lizard on Mars Found By Rover, NASA Photo, UFO Sighting News. — Captain (@Uredda)August 22, 2015

How does your brain process basic points of light into a shape and then into recognizing it as an object?
If you think about it, anything you see is just a collection of light patterns falling on your retina. There's nothing inherently meaningful about the pattern of lines that make up a coffee cup but as this info flows through the higher portions of the visual system as you get more toward the front of the brain, the hypothesis is that those patterns get matched up with templates for things you see all the time.

If you see lines that are a cylinder with an arc coming off of it, it's a coffee cup-like shape, those random features get matched up to these templates and that allows the categorization and object identity and recognition to occur.

And at some point your rational brain has to step in and decide whether to believe the Virgin Mary is appearing to you or whether there is an iguana on Mars or not. Vision doesn't overtake rational thought.
There are systematic ways to test these things. For the Mars pictures, if you really wanted to, you could take a bunch of random areas all over the picture and look for pixels that look like various meaningful objects. You'll probably find that a bunch of them do—you'll find mermaids and cats and butterflies and shoes and grandmothers and other stuff, but if you were to do that, you would then say what's the likelihood that all this stuff exists in this picture, and you'd be like, Oh, OK, no… and then seeing the mermaid starts to become less meaningful.


And you don't need science to explain why that's not, say, a mermaid on Mars.
Especially on the rocks and on the dirt.

There is more than 'a spoon' What is this? — Raul Alvarez (@ralvar314)September 2, 2015

What are we born knowing how to recognize? Obviously we aren't born to see Elvis in a potato chip, but are we born knowing how to recognize faces?
We're not necessarily born to recognize anything. But we are born with regions of our brain that seem to be biased to learn to recognize some things better over time compared to other things. A newborn infant can't even really see; their eyes are undifferentiated, they can't really recognize anything. But over time—reliably across everybody—some parts of the brain get really good at recognizing things like faces and other parts of the brain get good at recognizing things like nature scenes.

It's not as though we're born with the ideal coffee cup or the ideal ruler in our brain or anything else. We just experience things and those experiences give us those templates, and we match incoming sensory stimuli to them.

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So someone with a lifetime as a hardcore Catholic is going to be biased towards seeing the Virgin Mary in the side of a building.
Exactly. That's why some people have a tendency to believe more; if you have tons of experience with pictures of the Virgin Mary, there's a greater likelihood that those higher parts of your visual system are going to match up the arbitrary stuff you're seeing to the template of the Virgin Mary you have in your brain. And that increases your belief that what you're seeing is meaningful on some level. If you don't have as strong a template, it's harder to match the random stuff up to it. Someone from a culture without the Virgin Mary would never see her.

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