For a scientific experiment, 5 monkeys were locked in a cage with a banana at the top of a ladder.
Everytime a monkey went up the ladder the others recieved a hoze bath, so after a few baths, they decided to punch anyone who went up the ladder.
After a while, no one dared to go up the stairs, so the scientists randomly replaced one of the monkeys with a new one.
This new monkey immediately went up the stairs and got punched, he never tried again. A second monkey was replaced, the same thing happened, with the first replacement participating in the fight.
This went on and on and then the whole group of monkeys was replaced, and even though neither of them had ever had a hoze bath, they kept on punching whoever climbed the ladder.
After then, one of the scientists asked the other "Why are they even fighting anymore?".
The other answered:
"They don't know! But that's how it always worked around there"
