Monkeys and assumptions

From 'Tinkertoys', a story about monkeys:

Five monkeys were put into a cage with a platform that had a dangling banana on it.
The first monkey decided to get the banana and hopped up onto the platform to grab the banana. When he did that, all of the other monkeys below got sprayed with cold water.
After that, researchers replaced the banana and the second monkey went onto the platform to grab the banana. The other four monkeys got sprayed with cold water. When the third monkey tried to go onto the platform, the other monkeys attacked it because they didn't want to get sprayed.
So none of the monkeys would go onto the platform to grab the banana dangling there because the other monkeys would attack.

They replaced one of the monkeys with a new monkey. This new monkey saw the banana and tried to go onto the platform to grab it, but the other monkeys attacked it. It didn't know why it was attacked but it realized that if it tried to get onto the platform, it would get attacked so it stopped trying.

They replaced another original monkey with a new one and the same thing happened. But the monkey who didn't know about the cold water joined in and attacked the new monkey when the new monkey tried to go onto the platform to get the banana.

Eventually, they replaced all of the monkeys with ones that had no idea about the cold water. The monkeys didn't know why they attacked any monkey who tried to get onto the platform, but they continued to do it even though the cold water mechanism was turned off. This is a lesson about assumptions. Just because something is done a certain way, doesn't mean there's a good reason behind it.