It doesn't look like much, but this optical illusion will make you question just about everything you see from now on.
The two square shapes appear to be two completely different colours. The top shape looks like it's dark grey and the bottom a shade of white. Now use your finger to block the area of the image where the two squares meet and realize that THEY ARE EXACTLY THE SAME COLOUR.
Still don't believe? Take a look at this edited version with the shaded area in the middle removed.
The theory is summed up nicely in a paper for the American Scientist by Purves, R. Beau Lotto and Surajit Nundy:
"In the Cornsweet effect, opposing luminance gradients that meet at an edge make physically identical adjoining regions look differently bright. Specifically, the region adjacent to the lighter gradient appears brighter than the region next to the darker gradient."
In the same paper, the writers theorize that the illusion is an effect of the brain creating an image that best accords with what "similar stimuli have typically signified" in the past.
In this case, our brain assumes the image is three dimensional and lit from the top left (even though neither of these facts is true). The brain basically thinks the top image is being lit by the sun and the bottom is in the shade, thus creating the illusion.
Just one more reason to QUESTION EVERYTHING.
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This optical illusion moves in waves as your eye traverses the image.
Modulated Diamond Field
This optical illusion expands and contracts as your eye moves across the screen.
This optical illusion expands and contracts as you focus on different areas of the image.
Look closely. This wavy zebra-like pattern gives off the illusion of cylindrical turning.
Psychedelic Color Vortex
This psychedelic color vortex pulsates with a mighty illusoriness.
The sharp/fuzzy contrast creates an optical illusion that makes the circle's pattern move when you move your head closer to the image.
The Rippling Eye
This pattern -- which resembles an eye -- sends ripples moving outward from the center.
This illusion gives off the sense of infinite expansion.
These overlapping circles give off the impression of gear-like circular movement. Try to make the motion stop.
Irregular Circular Vortex
This vortex moves subtly as the eye travels across the image.
Are these lines parallel or curved?
Try and find the black dots.
The circle rotates as you move your head closer to the dot.
Look at the columns closely.
Stare at the black dot long enough and watch the grey area disappear.
NEXT: Unintentionally Sexual Optical Illusions
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