There’s an experiment attributed to Harry Harlow. Five monkeys are placed in a cage, with a ladder and a banana hanging from the ceiling. Whenever a monkey climbs the ladder to grab the banana, all monkeys are sprayed with ice cold water. After a few times, monkeys know better and nobody tries climbing the ladder. Then, one monkey is replaced. The new arrival wants to get the banana, but as soon as he climbs the ladder, the other four start beating him – they want to stay warm and dry. After a few attempts, the new monkey conforms to the group and stays down.