The photo showed a number partially hidden inside a black and gray striped circle, with the caption, “What number is in the picture?”.
Thousands of people from all over the world watched the “visual puzzle” after it spread on Twitter, and came to very different conclusions about the hidden numbers, the British newspaper “Daily Mail” reported.
The responses of the participants varied in trying to solve this puzzle, which included, according to its publisher, the numbers 3452839.
Optical illusion works by playing with contrast sensitivity, an important measure of visual function, allowing us to perceive the difference between objects and their backgrounds.
This comes in handy in real-life situations such as driving in low light or fog, where a higher level of contrast sensitivity is required because the contrast between objects and their backgrounds is reduced.
In the case of a published “visual puzzle”, the numbers are on a level, and the swirls are on the other side.
While people with higher levels of contrast sensitivity were more likely to be able to see all seven numbers at once, many could only see 3 numbers (528), while others could see 4 numbers (5283). Knowing 5 numbers is 45383.
One of them succeeded in recognizing all the numbers, noting that it was difficult to see the first and last digits of the number inside the circle.
It is worth noting that poor contrast sensitivity can be a symptom of eye diseases including cataracts or glaucoma.