From the devilish dress that confused half the planet to the competitions that keep challenging eyes and brains, optical illusions never cease to amaze. In recent hours, portals like Reddit and other social media have been flooded by a relatively simple image that proposes the following: There are twelve black dots in it. The statement doesn't lie, but there is a small problem: we cannot see them all at the same time…
Here we go again: an image with a simple pattern, composed of squares that form a kind of grid. In the image we find a total of 12 black dots, which to tell the truth are nothing special when observed one by one. Now… try to see them all. Bring the image closer, change its size, you can also rotate it, but the effect is the same. If you keep moving your eyes, the most likely thing is that you see six or eight dots, although in most cases, those who have observed the image report no more than four dots. That said, the questions arrive: Are our eyes? Is it the brain? Is the blame on both? Is there something we don't know?.
The image was shared on Facebook by psychology professor Akiyoshi Kitaoka from Ritsumeikan University, but apparently it is not his work; instead, it is inspired by the "extinction illusion" linked to French scientist Jacques Ninio, which in turn is based on another optical illusion, the "grid illusion" by Ludimar Hermann. In very relaxed terms, the 12-dot illusion exploits limitations in peripheral vision. When a black dot is in the center of our vision, we can recognize it without problems, but the rest of the content is subject to the "interpretation" of the brain. The predominant aspect of the image is the gray grid, so our brain concludes that the grid extends, completely ignoring the black dots.
In fact, another element that brings us closer to Hermann's illusion is that if we observe the intersections of the gray lines, we will see very faint "white spots". In essence, this is caused by a lack of contrast. When there is less contrast at the intersections (more gray than white), the brain reports that the point where gray lines cross is lighter. I think my head hurts already...
