What You See Isn’t Always What You Just Saw
Nearly 175 years ago a Swiss crystallographer named Albert Louis Necker discovered that the line drawing of a cube could jump back and forth in our vision depending on how we look at it. In other words, our brains can suddenly discover a new way of seeing the same thing.Mark Newbold’s Animated Necker Cube
is an entertaining example of how this works. Optical illusions are fun, and if you want to see the case of the mysterious disappearing purple dots, go to the Sandlot Science Illusion of the Month
. The Sandlot Science website has a collection of engaging illusions presented in a "guided tour”, and students of complexity science will especially enjoy the graphic
that shows dramatically how a minor movement makes a major difference.
There is even an interesting personality experiment
developed by Dr. Peter Naish,
a lecturer in psychology at the Open University, the largest university in the United Kingdom, presented in conjunction with the BBC. The test, which takes about five minutes, relates certain personality traits to the way the observer sees and interprets the ambiguous and illusive Necker Cube. The results may surprise you.
For a more in-depth consideration of optical puzzles and cognitive response, an article on "Inconsistent Images”
by Peter Quigley, of the philosophy department of the University of Adelaide, offers analysis of Necker cubes, Escher drawings and the challenging idea of "impossible pictures” and pictures that are oddly incomplete. He uses still and animated illustrations in his discussion. Impossible pictures can be described mathematically only when using the tools of inconsistent mathematics and paraconsistent logic, he writes. That means advanced math and advanced logic that is tolerant of inconsistencies is needed to describe such pictures. Our brains, however, can find ways to reconcile inconsistent images. Basically, we find ways to impose consistency on our world even when our imposition isn’t completely justified by the evidence.
For more explanations, Michael Bach, a professor at the University of Frieberg in Germany, has written a brief primer on Optical Illusions.
The professor has also assembled an interesting collection of 72 Optical Illusions and Visual Phenomena