Archive for 08/01/2009 - 09/01/2009
The Orbison illusion is an optical illusion that was first described by the psychologist William Orbison in 1939. The bounding rectangle and inner square both appear distorted in the presence of the radiating lines.
The background gives us the impression there is some sort of perspective. As a result, our brain sees the shape distorted. This is a variant of the Hering and Wundt illusions.
At first impression most people dimples.In the absence of an obvious light source most people place an imaginary light source above the image (being earthlings living under the sun i suppose this is only natural). Because of this pre-conception we now imagine a shadow being cast at the top of the circles and light being caught on the bottom that is our assumption of where the light is coming from forces us to see indentations.
When slightly tilted line segments are aligned horizontally like the figure, the whole array appears to tilt toward the tilt of the line elements. This is a reversal of the Zollner illusion or acute-angle contraction.