We love a good optical illusion here at Creative Bloq, and this has to be one of the best. It's a classic illusion that was first written about way back in 1861, and it continues to baffle people today.
The Hering Illusion comprises a two parallel lines over a radial background. The parallel lines (red in the example below) appear to bow outwards... but do they really?
Image 1 of 2
Click right to see the illusion without the radial lines(Image credit: Fibonacci, CC BY-SA 3.0 DEED, via Wikimedia Commons )
The two red lines are completely straight(Image credit: Fibonacci, CC BY-SA 3.0 DEED, via Wikimedia Commons )
Whether you use a ruler or remove the radial lines in Photoshop, the conclusion is the same: the red lines are straight. So why don't we see them as straight?
The Hering Illusion is named after the German physiologist Ewald Hering, who was the first person to write about it. Hering himself believed that the illusion was caused by the brain overestimating the angle at the points of intersection between the lines, which some scientists have since put down to lateral inhibition in visual cortex.
However, some disagree with Hering's original hypothesis and think that the illusion is caused by a temporal delay that causes our visual system to extrapolate information in order to predict how the world will look in the next millisecond. The image isn't moving, but the radial lines trick our visual system into thinking that it is, which causes us to perceive the lines as curved.
(Image credit: Hans Kuiper)
There are several variations of this famous optical illusion, including the Orbison illusion and the Wundt illusion, which has an inverted effect. Hans Kuiper created the square-shaped variation Three in One above based on Square of Three by Reginald H. Neal. In this case, it appears as if the square shapes have diagonal lines, but all of the purple lines are actually straight.
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Joe is a regular freelance journalist and editor at Creative Bloq. He writes news, features and buying guides and keeps track of the best equipment and software for creatives, from video editing programs to monitors and accessories. A veteran news writer and photographer, he now works as a project manager at the London and Buenos Aires-based design, production and branding agency Hermana Creatives. There he manages a team of designers, photographers and video editors who specialise in producing visual content and design assets for the hospitality sector. He also dances Argentine tango.
