Optical Illusions are one of the most practical ways to learn about vision and perception. Various types of optical illusions illustrate some of the different aspects of vision perception. Furthermore, some of the exercises on the Exploratorium website are not actually illusions but really just tools for teaching about color perception such as the Mix and Match exercise, in which the viewer can learn the difference between mixing colors in print and mixing colored light.
Exercises like "Shimmer," "Depth Spinner," and "Squirming Palm" are similar in that they show how the eye and brain deal with motion. I noted that some of these exercises were actually difficult to do; the effect was not immediately apparent to me. Some of the more traditional optical illusions are exhibited on the Postcard page, where exercises like the old and young woman can show how the eye can be trained to detect various patterns. The "words and colors" exercise also shows how the eye and the brain can sometimes get in each others' way.
Learning about optical illusions through the experiments on these websites has been helpful in understanding the way perception works: our eyes aren't necessarily lying to us but our brain often distorts what we see based on our assumptions or expectations, as in the Leonardo da Vinci "Mona Lisa" exercise. Also, what our eyes take in as visual information is then interpreted by the brain. I was interested in all the illusions and exercises, as it proves that people should not always believe what they see. In the future I will try to apply the information on visual perception to the way I interpret the world. For example, the information on both sites that pertains to motion perception is useful in understanding common every day phenomenon related to driving: when we watch the wheels of cars speeding along a highway, for instance, it can suddenly seem that the wheels are turning in the opposite direction.
