What is curvature blindness? Scientists baffled by weird optical illusion

The weird nature of a new optical illusion shared by a Japanese scientist has people confused, with many bending their minds to identify the fine 'line' between reality and what our minds perceive.

The illusion is described and explained in the journal i-Perception, and has been dubbed "curvature blindness".

In the image, you see multiple pairs of zig-zag and curved lines with three background colours – white in the upper left corner, black in the bottom right and grey in between.

The lines in the upper left and bottom right corner appear curvy like sine waves, while those with the grey background appear to have a sharper zig-zag-like pattern.

However, the interesting bit here is – all of these lines are curved and none of them have that zig-zag pattern. A closer look at the grey background could help you identify that the curved, dark lines that are running from top to bottom appear to carry the zig-zag pattern, even though they are curved in reality.

It is still unclear why the human brain perceives a curve as a sharp corner.

According to lead researcher Kohske Takahashi, it could be because corners are easier to see than curves when our brains are confused.

"We propose that the underlying mechanisms for the gentle curve perception and those of obtuse corner perception are competing with each other in an imbalanced way and the percepts of a corner might be dominant in the visual system," Takahashi explained.