This week, we explore the mysterious and fascinating world of optical illusions. The National Institute of Environmental Health Sciences has put together a great page of images to delight and confound. Check out the NIEHS Kids Page of Optical Illusions and see for yourself. The Man in the Coffee Beans was my favorite because I literally jumped out of my chair when I found him!
Optical illusions fool us for different reasons. Some rely more upon perception than optics. For example, take the one where you are asked what color you see when the word “blue” is colored green. Our brain perceives one thing (as we read the word “blue”) while our eyes see something else (the color green). Other optical illusions, like those involving after-images, take advantage of how the eyes function.
Some optical illusions, like 3-D puzzles, rely upon how your eyes work together. If you are blind in one eye, like me, you won’t be able to see these kinds of optical illusions. (When I was younger, I had a book of illusions that suggested pointing both index fingers at each other over the bridge of your nose. Supposedly, if you pulled your fingers apart very slowly and stared straight ahead, you would soon see a small “hot dog” type image floating over your nose. Try as I might, I could never make this illusion work because it relies upon the viewer having three-dimensional vision).
If you like visual puzzles, check out the work of artists who specialize in creating optical illusions, like the late M. C. Escher.