Optical Illusion with "Color Consistancy" and "Shapeshifting"
Akiyoshi Kitaoka, a Professor of Psychology at Ritsumeikan University in Japan, specializes in optical illusions and has been making them for over a decade. It might be hard to swallow the truth, but there is no red in this photo at all, only pixels of color that appear red relative to the other colors. Kitaoka's picture uses something called color constancy. To understand the concept, it's helpful to consider the brain's purpose and how it functions. The goal of your brain is not to memorize and record every piece of data it receives—that would be impossible—but to generate a complete picture of the world that we can recognize and understand. In the case of color, specialized neurons in the primary visual cortex compute ratios within the eye's cone cells, which are responsible for color vision. A breakthrough in understanding the concept came in 1967 by studying goldfish. "If the cell is excited by red light in the center," wrote Nigel Daw in '67, "then it will also be excited by green light in the periphery, and inhibited by green light in the center or red light in the periphery." In other words, your eyes will send color signals to your brain partially based on other colors it sees and the relative difference between those colors. This is why you can look at an entirely green-gray photo and see red.
For another great Japanese optical illusion, be sure to check out the shapeshifting objects out of Meji University.