New optical illusion reveals you probably have 'curvature blindness'

A Japanese psychologist has designed a new optical illusion he claims can prove humans suffer from "curvature blindness" – and probably were never aware of it.

The simple image consists of light and dark grey dashes linked to make parallel lines in waves and zig-zags across a background coloured white, grey and black.

However, if you look closely, the zig-zags don't actually exist.

Dr Kohske Takahashi, a psychologist at Chukyo University in Japan, says the apparently sharp edges are simply a quirk of the human brain.

He calls it "curvature blindness", which occurs on the lines where the light and dark grey dashes end at the peak or valley of the curve. In contrast where the dashes cross the peak or trough, the brain continues to see the lines as wavy, The Telegraph UK reports.

Dr Takahashi believes humans may have evolved to see corners ahead of curves because of the artificial world we live in.

And where there is confusion in his graphic – where the light and dark grey dashes move across a change in the background colour – the human brain chooses to see a sharp edge rather than a curve.

"I'd say that our eyes and brain may have been evolutionarily adapted to detect corners more efficiently than curves," Dr Takahashi said.

"We are surrounded by artificial products, which have much more corners than natural environment does, and hence our visual.

"This visual phenomenon doesn't cause the problem in our everyday life, otherwise someone should have found this illusion earlier."