Humans are easily fooled, whether by meticulously designed human tricks, accidental environmental factors, or highly effective techniques mastered through diligent practice; people can be easily tricked. One reason for this outcome is the micro-effect in human perception. If a stimulus is maintained below a certain level, humans will not notice its presence. Because of this reason, a magician can make the Statue of Liberty disappear after a flourish of movement in the dark. The audience does not know that they are sitting on a slowly rotating platform. This platform rotates very slowly, so no one can notice it. When the curtain on the platform is pulled back where the Statue of Liberty appeared, it looks like it has vanished.
Some professors like to use experiments to demonstrate the perceptual flaws caused by contrast. They will have students place one hand in a bucket of hot water and the other hand into a bucket of cold water. Then they will suddenly ask the students to place both hands into a bucket of lukewarm water. Although both hands are in the same bucket of water, one hand feels as if it was just placed in cold water, and the other hand feels as if it was just placed in hot water. When people realize that simple contrast alone can easily deceive perception in a place where thermometers do not err, and they realize that cognition and perception are the same, they will be deceived by simple contrast. In this way, they can not only understand how a magician tricks people but also understand how life plays tricks on people. The tendencies within the human perception and cognition system that are generally very useful often make mistakes, and if one does not guard against this carefully, they will be easily manipulated by others.