A simple image becomes viral, internet users racking their brains (or changing their glasses!), and a divisive question: “What number do you see?” If you’ve recently come across this famous black and gray spiral on social media, you’ve probably also tried to discover its secret. But be careful, this visual game conceals much more than meets the eye…
When our brain plays tricks on us (visually!)
Why does such a banal image suddenly leave us so confused? The spiral illusion works by playing on a well-known principle of our vision: contrast sensitivity. Simply put, the more appropriate you are at characteristic the subtle between black, white, and gray, the more likely you are to notice all the hidden numbers.
Some people only see three, others count five, seven, or even a few more. So, who’s right? Well… everyone! And that’s precisely what makes this illusion so appealing.
Figures that vary relying on… you!
Contrary to popular belief, it’s not your creativity that’s playing tricks on you. Here’s why your eyes may feel a reality different from that of your neighbor:
Your contrast sensitivity: Our eyes are not all wired the same way. Some people are naturally more sensitive to nuances of light and shadow.
The quality of your screen: A high-definition screen can discover details that others completely obscure. Yes, technology plays a role too!
Your gaze position: Tilting your head slightly or moving away from the image can suddenly know a previously invisible number. Surprising, isn’t it?
Result: this illusion becomes a fun little test… but one to be taken lightly!
A fun game (but not a medical test!)
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