Optical Illusion Goes Viral Because People Can’t Believe What They’re Looking At

Take a look at the video above and you'll probably see a square traveling left to right on the gradient, changing color as it goes. But what if you discovered the moving square actually stays the same color the whole time? That's right, once again our eyes are deceiving us with another optical illusion.

This video is just one example of a lightness illusion, which was posted by experimental psychologist Akiyoshi Kitaoka, who studies visual perception. A professor at Kyoto's Ritsumeikan University, Kitaoka's faculty page is filled with incredible optical illusions. He also often uses Twitter to send intriguing illusions out into the world, forcing us to examine why our eyes may be deceiving us.

There are many types of lightness illusions, including the Checker Shadow Illusion, but how do they work? It's all about perception. First, we must understand that when our eyes look at something, light levels vary and they must take in a lot of information. This includes reflectance (how much light bounces off a surface), lightness (how our eyes perceive the reflectance), brightness (the perceived intensity of the light), and luminance (how intense the light is based on the sensitivity of our visual system).

When we are trying to pick out an individual object, while processing all this information, our brain may discount some of the factors in order to allow our eyes to perceive the object. “A gray surface in sunlight may have much higher luminance than it has in the shade, but it still looks gray. To achieve the task of ‘lightness constancy,' the visual system must discount the illumination and other viewing conditions and estimate the reflectance.” writes Professor Adelson, the man who first published the Checker Shadow Illusion.

In these cases, our brain does its best based on past experience in 3D environments, which often results in errors when looking at 2D designs. As the authors of a 2007 study astutely note, “Sometimes the best way to understand how the visual brain works is to understand why it sometimes does not,” thus explaining why optical illusions have long fascinated scientists.

This demonstration shows how lightness illusions cause your brain to perceive different colors.

Enjoy more lightness illusions shared by Akiyoshi Kitaoka.

h/t: [IFLScience!]

Related Articles:

Can You Believe There Are No Red Pixels in This Image?

Mind-blowingly Mesmerizing Optical Illusions by Akiyoshi Kitaoka

Mind-Bending Optical Illusions Appear to be Alive

Jessica Stewart

Jessica Stewart is a Contributing Writer and Digital Media Specialist for My Modern Met, as well as a curator and art historian. Since 2020, she is also one of the co-hosts of the My Modern Met Top Artist Podcast. She earned her MA in Renaissance Studies from University College London and now lives in Rome, Italy. She cultivated expertise in street art which led to the purchase of her photographic archive by the Treccani Italian Encyclopedia in 2014. When she’s not spending time with her three dogs, she also manages the studio of a successful street artist. In 2013, she authored the book 'Street Art Stories Roma' and most recently contributed to 'Crossroads: A Glimpse Into the Life of Alice Pasquini'. You can follow her adventures online at @romephotoblog.
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