Optic illusions have been a source for interest for many years.
Joseph Jastrow’s work on optical illusions was one of his many renowned academic interests. His landmark paper, “A Study of Zollner’s Figures and Other Related Ilusions”, was published in “The American Journal of Psychology” in April 1892.
Joseph Jastrow was instrumental to popularizing psychological science amongst the general public. He regularly wrote for leading magazines like Popular Science Monthly. This included an article in 1899 entitled ‘The mind’s eye’ that featured the rabbit-duck illusion.

Edwin Boring, a prominent experimental psychologist and historian of psychology, was also well-known for his pioneering work on visual perception, especially ambiguous illusions, such as the ubiquitous young lady, old woman figure.
Shades of Gray

Square A and square B are actually the same shade. Edward H. Adelson, Professor of Vision Science at the Massachusetts Institute of Technology, created this amazing illusion. He is also a member of the department Brain and Cognitive Sciences at Massachusetts Institute of Technology. Professor Adelson says that the illusion is caused by your visual system trying to…
To determine where shadows are located and how to compensate, to determine the gray ‘paint” that belongs to the surface.
Square B is in the shadow of Square A, while Square A is not. Your perceptual field has evolved so that you can automatically correct any changes in the appearance a color makes when it’s in shadow. Richard Wiseman (Professor of Psychology and Public Understanding at the University of Hertfordshire) has provided a great explanation for why squares A & B look so different visually.

Your brain and eyes see the same shade of grey, but then your brain thinks, “Hold on, if a square within a shadow reflects the exact same amount of light, then it must be a lighter shade of gray.”
Dynamic Illusions
Expect the Unexpected website has new versions of optical illusions.