This story starts with a cage containing five gorillas and a large bunch of bananas hanging above some stairs in the center of the cage. Before long, a gorilla goes to the stairs and starts to climb toward the bananas. As soon as he touches the stairs, all the gorillas are sprayed with cold water. After a while, another gorilla makes an attempt and gets the same result—all the gorillas are sprayed with cold water.
Every time a gorilla attempts to retrieve the bananas, the others are sprayed. Eventually, they quit trying and leave the bananas alone. One of the original gorillas is removed from the cage and replaced with a new one. The new gorilla sees the bananas and starts to climb the stairs. To his horror, all the other gorillas attack him. After another attempt and attack, he knows that if he tries to climb the stairs he will be assaulted. Next, the second of the original five gorillas is replaced with a new one. The newcomer goes to the stairs and is attacked. The previous newcomer takes part in the punishment with enthusiasm.
Next the third original gorilla is replaced with a new one. The new one goes for the stairs and is attacked as well. Two of the four gorillas that beat him have no idea why they were not permitted to climb the stairs or why they are participating in the beating of the newest gorilla. After the fourth and fifth original gorillas have been replaced, all the gorillas that were sprayed with cold water are gone. Nevertheless, no gorilla will ever again approach the stairs. Why not?
“Because that’s the way it has always been done.”