The way we perceive things depends on our experiences. If we have not already stored something our memory, the brain might store new information in the wrong compartment; it might even take us for a ride. We encounter situations where the brain plays tricks on us, simply because our grey cells respond automatically to experiences and expectations. We all know about mirages, the optical illusions which can lure thirsty desert travelers to disaster. Mirages make us to think we see expanses of water, or they make remote parts of a landscape seem much closer than they really are. Often mirages appear on the high way, making us think that the road ahead is slick with water.
Such apparitions can be explained through reference to conditions in the atmosphere, but our perception can also be deceived when the brain malfunctions. This can happen as a side effect of certain illnesses, hallucinations or the influence of drugs. Often, such malfunctions can make you see strange things. A typical example is the white mice that alcoholics may see during the first phase of withdrawal from alcohol. In a wider sense, metal delusions can also be counted among these brain deceptions. Delusions include persecution complexes, excessive jealousy or delusions of grandeur. They stem from the beliefs which are out of touch with reality or false images a person might have about his or her identity.