All the lines in the curvature blindness illusion are the same shape.
A new optical illusion discovered by researcher Kohske Takahashi once again challenges the veracity of what we perceive. The new illusion, which Takahashi calls the “curvature blindness illusion”, was just published in the journal i-Perception.
In the image below, the grey and black lines all appear to have the same shape in the upper left and bottom right sections, which have white and black backgrounds, respectively. They are all the shape of a basic sine wave. But in the grey middle section, half of the lines appear to be composed of sharp corners. In reality, all of the lines are sine waves all the way across.
The complete curvature blindness illusion:
It’s still unclear exactly why this illusion works, but it has to do with whether each curve is entirely either grey or black, or whether it is half black, half grey. In this second case, our brain perceives the curve as a sharp corner. Takahashi proposes that this is because when our brains are confused, corners are easier to see than curves.
“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 corner might be dominant in the visual system,” he writes.
Whatever the reason, it’s always fascinating to witness the limitations of our own perception, and illusions like these help advance our understanding of how our brains process images.