The cage effect: if a person bought an empty cage at home, then after a period of time, he will in order to use this cage a bird without raising the cage back away, is this person but was off the cage for alienation, become the captive cage.
The cage effect is a famous psychological phenomenon, also known as the "birdcage logic" is one of the ten difficult to get rid of human psychology, the discovery is an outstanding modern psychologist James. The "cage effect" is a very interesting rule, people will get a chance in the original do not need goods, consciously add more things that they don't need to unconsciously.