The 2016 winners of the Neural Correlate Society’s Best Illusion of the Year Contest may not only challenge your sense of reality, they could turn what you think you know about the world on its head.
Every year, the contest challenges everyone from artists to ophthalmologists to come up with illusions so mind-bending, you may never understand how they work. The contest solicits public submissions, creates a top ten list using a panel of judges, and then lets the public vote on their top three.
This year’s winners, Mathew T. Harrison and Gideon P. Caplovitz of the University of Nevada Reno, created something truly mind-boggling—a set of seemingly moving black-and-white shapes that aren’t really moving at all. When you take a look at the dots, you’ll realize that they are not in motion, even though the configurations of black-and-white specks seem like they’re morphing into all kinds of designs.
The illusion isn’t just a trippy trick—it’s an example of drifting Gabors. Gabor patches are also known as “Gaussian-windowed, drifting sinusoidal luminance patterns.” The concept is more simple than it sounds. A sine wave can be seen through a grate-like phenomenon that makes it appear like a moving object. Gabors are sometimes used to test or train vision. In this case, the context of many Gabors whose filters drift makes it look as if all of the spots are moving around. This isn’t the first time Caplovitz has confused onlookers: He’s a neuroscientist who’s been in the contest’s top ten before.
In second place is Kokichi Sugihara, an engineer who has created something truly bizarre. This seemingly impossible illusion, which Sugihara calls the “ambiguous cylinder illusion,” tricks the brain with objects that look square, but seem to become circular when placed in front of a mirror.
“We cannot correct our interpretations although we logically know that they come from the same objects,” writes Sugihara. “Even if the object is rotated in front of a viewer, it is difficult to understand the true shape of the object, and thus the illusion does not disappear.”
That statement characterizes the weirdness of watching an object morph from squares into circles and back again, but it doesn’t explain the illusion. It took 3D printing specialist “Devon” from the Make Anything channel on YouTube reverse engineering the illusion to reveal what is going on. The trick relies on a cylinder that looks square from the bottom, but has curved sides that, when placed next to a mirror at the right angle, look circular instead. The trick relies on a lazy brain that tries to fill in all four sides with the shape it perceives. Not bad for a simple cylinder.
The contest’s third place winner, “Silhouette Zoetrope” by Christine Veras, is an empty, zoetrope-like object that seems to leap to life when spun. But unlike a regular zoetrope, it doesn’t contain animated illustrations. Rather, the light of the cylinder makes it look like birds on the outside of the zooetrope are inside in silhouette. And even more weirdly, the birds seem to fly in the opposite direction that they point when stable.
Veras, a Ph.D student in art, design and media, created the illusion by combining multiple visual effects. In a release about the prize, Nanyang Technological University explains that multiple visual phenomena are at play. The flashing glimpses of birds in different positions tricks the brain into thinking that they are moving with a phenomenon called stroboscopic apparent motion, while an accommodation conflict between the eye’s desire to focus on multiple images at different depths makes it look like the birds are inside the spinning zoetrope. And then there’s Emmert’s law, which makes objects of the same size appear to be different in physical size when their perceived distance increases.
Essentially, all three illusions rely on the brain to interpret information from the eyes, but the brains fill in information that isn’t necessarily correct depending on what they expect to see. If it sounds confusing, it is; the release notes that the relationship between sight and perception is still being studied.
Ultimately, what we see and what we perceive are not always the same thing. That makes for some stunning stumpers and provides plenty of fodder for scientists looking to unravel the mysteries of human cognition. Until they figure it out, the rest of us will just look on...and scratch our heads.