Art as they say, is subjective, what one person considers a priceless masterpiece others might see as nothing more than a giant black square… But there’s one very specific kind of painting that most everyone sees the same way- the kind with the weird eyes that seem to follow you around the room.  So what causes this optical illusion of sorts and how do artists achieve this effect?

It turns out, for even a moderately skilled artist, this “ubiquitous gaze” effect isn’t a difficult thing to achieve. In a nutshell, all you need is a little illusion of depth, so the person depicted appearing at least somewhat 3D despite being on a 2D canvas, and to direct the gaze of the eyes such that they would be looking at someone standing right in front of the picture.

So what exactly is going on here in our brains that then makes it seem like the eyes follow you even if you move away from being front and center? As demonstrated in 2004 by a team of researchers from Ohio State University, as you move to the side, the “near” and “far” points of the 2D image don’t really change. These near and far points are defined as visible points that, if the image was 3-dimensional, would appear nearest and furthest away from the viewer at a given angle.

Summarising their findings, co-author of the paper James Todd had the following to say:

The idea is simple – no matter what angle you look at a painting from, the painting itself doesn’t change. You’re looking at a flat surface…. The key is that the near points and far points of the picture remained the same no matter the angle the picture was viewed from. When observing real surfaces in the natural environment the visual information that specifies near and far points varies when we change viewing direction.

When we observe a picture on the wall, on the other hand, the visual information that defines near and far points is unaffected by viewing direction. Still, we interpret this perceptually as if it were a real object…

Thus, because the perspective, shadows, and light on the painting don’t change as you move around, if the eyes in the painting would be staring directly at the observer if said individual is standing in front of the painting, it creates something of a mild optical illusion in your brain such that the eyes will continue to seem to stare at you as you move to the side.

In contrast to the eyes following you trick, if the artist tweaks the painting a bit such that the eyes are looking off somewhere else instead of directly out at a potential observer, no matter where you stand, the eyes will never seem to be looking at you.

The technique first began popularly showing up in art around the 14th century when the artist and architect Fillipo Brunelleshi introduced the art world to the idea of “linear perspective”, linear perspective being painting with the idea of everything in the picture converging on a specific point on the horizon, creating the illusion of depth. This, combined with skilled use of light and shadow, allowed artists to create masterfully realistic paintings, including sometimes of people that stare at you creepily no matter where you stand, and totally aren’t Scooby Doo villains stalking you with the intent to murder you in your sleep.

If you liked this article, you might also enjoy our new popular podcast, The BrainFood Show (iTunes, Spotify, Google Play Music, Feed), as well as:

• The Surprisingly Mysterious Life of Famed Artist Bob Ross
• The Revenge of Han van Meegeren, One of the Great Art Forgers of All Time
• Why People Stuck One Hand in Their Jackets in Old Photographs
• Why are Barns Traditionally Painted Red?
• Why was Lead Added to Paint?

Bonus Fact:

• Speaking of one of the most famous and valuable paintings in history being literally just a big black square on a white canvas, and just as unimaginatively named Black Square, in 1964, a new avant-garde artist was introduced to the art scene in the Swedish city of Gōteborg. The fresh new artist was Pierre Brassau and his work received rave reviews from critics and art fans alike. One critic in particular, Rolf Anderberg, was so overwhelmed by Pierre’s talent that he wrote the following review about his work, which appeared in print the morning after the exhibition: “Brassau paints with powerful strokes, but also with clear determination. His brush strokes twist with furious fastidiousness. Pierre is an artist who performs with the delicacy of a ballet dancer.” The reviews were almost universally glowing. All but one, that is.  One critic’s commentary on the new artist was short and to the point: “Only an ape could have done this.”The opinion was unpopular, despite that the pieces of art looked strikingly similar to “art” you commonly see stuck to refrigerators, produced by 2 year olds the world over.

  It turns out, though, that the “ape” review more or less hit the nail on the head. Pierre Brassau was actually none other than a young West African chimpanzee named Peter who lived in the Borås djurpark zoo in Sweden.  The mastermind behind the hoax was journalist Åke “Dacke” Axelsson. Axelsson worked for the Swedish tabloid Gotebors-Tidningen and came up with the idea of featuring the primate paintings in an exhibition in order to put the critics to the test- could they distinguish between the work of true, highly skilled avant-garde modern artists when compared to the work of a random chimpanzee? It turns out the answer is mostly no. Although it should be noted that we’re guessing the chimp couldn’t have painted a perfect black square. So that’s something I guess.

  And if you’re wondering, once the hoax was revealed, the critic who had previously compared Pierre Brassau with a ballet dancer, Rolf Anderberg, doggedly stuck by his assessment and stated that Pierre’s work “was still the best painting in the exhibition”.