Are you always in no that what you see matches reality?
Have you ever questioned an experiment in which two people are shown the same picture and one of them sees two faces and the other glass of wine? If so, you should be aware that sometimes what we see is not necessarily what really exist.
This phenomenon, in which our brain is taken by stimuli such as brightness, colour, tilt or movement and tricks, is called an optical illusion. There are many examples of optical illusions in our everyday life. For instance, you to compare the speed of a plane with that of a car, which would you say was moving more quickly? We may know it's the plane, but for the brain, the car may appear to be moving faster. Another example involves film animation because a series of slighlty varying images is produced in fairly slow succession, our brain will perceive them as static.