The world is full of optical illusions and many a time things may not look like as they appear. The information gathered by our eyes is processed by the brain, which has the ability to filter out unimportant things in order to single out opportunities and threats. It’s a highly advanced system—but it isn’t perfect. It can easily trick us into believing an optical illusion. By definition an optical illusion is the “dissociation between the physical reality and the objective perception of an object/event.” An optical illusion occurs because our brain is trying to interpret what we see and make sense of the world around us.
If you think you can easily identity an optical illusion, Kohske Takahashi, a psychologist at Chukyo University, Japan, has identified a new type of optical illusion, that’s sure to blow your mind. The illusion is called curvature blindness and is outlined in a new study published online in Iperception.
Here is the optical illusion:
These waves have consistent peaks and valleys like sine waves, and are divided into segments of dark gray and light gray. The background behind them is of black, white, and gray colours. So what kind of lines do you see in the middle, grayed-out part: wavy, straight, or both?
The reality is all the lines represented in the image are curvy, but a majority see alternating rows of straight-angled and wavy lines. In gray background, sometimes the bends appear to be a sharp zigzag. It occurs when lines have a dark line that runs from top to bottom (crest to trough).
In the paper, Takahashi explains the principle behind this illusion:
“The lines that appear to zig-zag are the ones in which the color changes occur at the peaks and valleys. The abrupt corner created by the cutoff between the dark gray and light gray makes it so the viewer perceives the curve as a sharp angle. This perception competes with the more accurate perception of a gentle curve.”
“It is notable that observers exactly ‘see’ an illusory zigzag line against a physically wavy line, rather than have an impaired perception. 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 corner might be dominant in the visual system.”
In other words, your brain might tend more toward seeing a corner when there’s confusion about whether it’s seeing a corner or a curve.
The illusion is a good example of how our brain process information.
Another optical illusion: