Optical illusion has people confused if these lines are curves or zig-zags

omg 14/12/2017

A new phenomenon called 'curvature blindness' has been demonstrated through an optical illusion.

A psychologist discovered that humans can exhibit the type of blindness and swap undulating waves for corners.

Dr Kohske Takahashi, psychologist at Chukyo University in Japan, created the illusion that appears to show a range of wavy lines and zig zags on a white, grey and black background.

But a closer look shows all of the lines are curved, there are no sharp peaks and the brain is simply adding them in.

On the grey background, the brain registers the shift from light to gray and mistakes the curved line to be one with sharp angles.

Dr Takahashi wrote in a report in i-Perception that the phenomenon occurs on lines where light and dark dashes end at the peak or valley of the curve. The brain mistakes the shift from light to gray at the curve and mistakes it for a sharp angle.

When the angular lines cross out of the grey area the brain can see the lines are wavy.

Dr Takahashi believes the illusion could be due to humans evolving to spot corners before they spot curves, and when the colours change the brain opts to identify corners.

However, he said that the brain doesn't appear to cause the phenomenon in real life outside of the illusion.