There are actually twelve black dots, but as Akiyoshi Kitaoka, the psychology professor at Ritsumeikan University in Kyoto, Japan, recently noted on Facebook, most people won’t be able to see them at once.
All twelve dots are really on the image, but most people are unable to see them all at the same time, making the dots seem like they appear and disappear with every blink. This occurs because the eye’s stimulated light receptors can sometimes influence the ones next to them, creating illusions.
In this particular image, tweeted by game developer Will Kerslake on Sunday, the brain can see some black dots but guesses when it fills in the peripheral vision. Because mostly grey lines appear in the periphery, the black dots don’t appear.
The image is a variation on the Hermann grid illusion, a diagram of black squares separated by white lines. Dark patches appear where the white lines intersect, but only in a person’s periphery.
How many dots can you see at once?
There are twelve black dots at the intersections in this image. Your brain won’t let you see them all at once. pic.twitter.com/ig6P980LOT
— 𝕎𝕚𝕝𝕝 𝕂𝕖𝕣𝕤𝕝𝕒𝕜𝕖 (@wkerslake) September 11, 2016
Muriel M. Delossantos