A simple interface, an ephemeral moment, a constrained set of tools, a curated version of life, the rise of cameraphones — these were catalysts for Instagram’s success. But there is also, and I’m sorry to use such a word but it does fit, a “magic” in the way the app could transform photos.

When Facebook ponied up to buy Instagram I joked Zuckerberg had just spent a billion dollars on camera filters. Soon, Twitter and other companies began to tout filters on their photo apps. Anyone could take a picture with their phone and make them look (somewhat) appealing — call it artistic or professional.

But that doesn’t feel like the whole story. That “magic” nags at something deeper in our brains, in our subconscious working behind the curtain during our interactions with the world. It nags at why we do and do not enjoy replications of life. Instagram filters dampen and brighten, tweak contrast and even tunnel the image. All of those changes make the image look less real, in some ways more closer to a painting than a high-def photo.

In fact, filters may just back the image out of something close to the uncanny valley.

Typically we think of the uncanny valley as that creepy almost-human zone for robots with skin-tone. But it seems like these same principles port to our enjoyment of art. We know the animal circuitry that processes our surroundings doesn’t appreciate unexplainable surprises. We search for signs of certainty everywhere we go. So our brains evaluate pictures, subconsciously, for visual cues that make us comfortable. And “more artistic” has always been code for “less real”.

Dr Angela Tinwell studies how the uncanny valley affects animation and illustration at The University of Bolton and says “increased levels of graphical fidelity on the part of the viewer raises expectations on how that human-like character will behave.”

“When the agent fails to live up to our expectations, that’s when they fall into the uncanny valley. We’re questioning — what’s wrong with it?”

Typical representation of the uncanny valley

And as Ahna Girshick, who earned a PhD from Berkeley in how our brains integrate visual information, notes, “Our attention tends to jump to the imperfections.”

So with a cameraphone picture, maybe the flash washed out skin tone. Or maybe the wrinkles around the eyes came through blurry. We breeze past these imperfections because they’re cameraphone pictures — so what? But subconsciously there’s a disparity in the levels of fidelity. Filter with Sutro or Hefe and we’ve smoothed the image over, evened things out. We’ve equalized expectations in a portrait.

“When the whole picture in itself is clearly stylized, that’s when they will escape the uncanny valley,” Tinwell says.

Like the multiple reasons for Instagram’s success, the reasons we enjoy filters don’t exist in a vacuum either. Tinwell points out color has an emotive value. Take a picture of your friends where the light causes a blue-grey tint and we see people with less vibrancy. They’re cold. Not a zombie, but trending in that direction. Filters can give subjects deep skin tone and darker color. Blood flow shows life, health. We’re making people more sexually attractive — selfies become the modern mating call.

But Instagram isn’t only pictures of people so filtering images may go beyond looking like a zombie—and to the root of art’s appeal: imagination. Impressionism is one of the most popular forms of paintings — yet the paintings do a very poor job of replicating reality. Starry Night doesn’t look “real.” Dr Kurt Gray of the University of North Carolina’s psychology department believes there’s something intoxicating about that incompleteness. Our creativity gets a workout.

“We want to leave some things to the imagination,” he says. “You have to use your mind to fill in the gaps….It allows us to fill in what we hope or expect to see in the scene.”

Think how often a picture looks better, more engaging, when turned to black and white—hues that look nothing like real life. We detect the contours of real life in the photo — get that framework of reality — and the image, subconsciously, becomes our coloring book, providing just enough guidance that the mind works to fill in the rest.

(Musicians may recognize this idea: the appeal of a song existing between the notes. Thelonious Monk once wrote, “What you don’t play can be as important as what you do play. A note can be as big or as small as the world, it depends on your imagination.” Listen to Miles Davis’s Flamenco Sketches to hear that idea in action. And anyone that prefers reading over television will resonate with the notion — let my mind show me the story, not a screen.)

Gray hadn’t considered the idea that photo filters might push an image out of an uncanny valley but did note psychologists have done very little to truly understand why people enjoy art, of any kind. “There’s hesitation because people want to say art is undefinable.”

I don’t want to give the impression I’m cooking up hard science. Maybe correlation is at work over causation, and no doubt there are myriad associative reasons why filters appeal to the eye. Sepia may evoke pleasure with memories of the good old days. But processing our surroundings and replications of our surroundings certainly exist along something far more complicated than X and Y axises. Tinwell and other researchers are showing that the two lines of the uncanny valley graph don’t begin to describe what’s actually going on in our heads.

“It can’t just be measured on two planes, based on perceived strangeness and perceived human likeness. It’s a multi-dimensional phenomena that has many facets and is actually as complex as understanding the human psyche,” Tinwell says.

Filters are just a nick of the surface. We know Instagram and Facebook deploy complicated algorithms to pour over photos to sell more effective advertising. But locked inside those images and all that data are countless, almost infinite stories about why we humans, with our fascinating brains, appreciate certain aesthetics or enjoy different representations of reality. It would be sad if we ever solved that mystery, or even got to a place where we truly believed that was possible. But it’s still fun to hunt around for the clues.

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