Scientists placed 5 monkeys in a cage with a ladder with bananas at the top. Whenever a monkey climbed the ladder, the scientists soaked the other monkeys with cold water. After several soakings, the other monkeys would beat up any monkey that tried to climb the ladder. Scientists then substituted monkeys one by one. Each new monkey was beaten by the others for trying to climb the ladder, even though none of them had experienced the cold water punishment. In the end, none of the monkeys knew why they beat up others for climbing the ladder.