The gray strawberries
Look at the photo. What color are the strawberries? Then move the eyedropper across the image.
The experiment starts as soon as the page has loaded (JavaScript is required).
Try the experiment: your result will appear here, next to what most people do.
What just happened (read it after the experiment)
What most people do: Almost everyone sees red strawberries.
Under a bluish filter, the pixels of the strawberries are gray or blue-green. Your brain, however, knows that a blue light bathes the whole scene: it “subtracts” that light and shows you the red strawberries it expects to see.
This mechanism is called color constancy: it lets you recognize a banana as yellow at noon and at sunset alike. The illusion was created in 2017 by the Japanese psychologist Akiyoshi Kitaoka.
Color is neither in the object nor in the light: it is a decision your brain makes.
More experiments
Sources
- Akiyoshi Kitaoka, gray strawberries illusion, 2017.
- David Foster, “Color constancy,” Vision Research, 2011.