Here is the experiment, monkeys were trained to retrieve a rock and give it to the experimenter and in return they would get a piece of cucumber. This became routine for the monkeys, it was their job.
Then two monkeys were set up side by side and their routine began, retrieve the rock get the cucumber, retrieve the rock get the cucumber, except then one of the monkeys was given a pay rise, they were given grapes for their rocks! This caused a revolt in the lower class monkey who was still on minimum wage. When he got the piece of cucumber he was outraged and threw the cucumber at the scientists. Why should one monkey get paid more than the other monkey? This was unfair! And so he protested!
What was really interesting was when this experiment was repeated in chimpanzees. In a few pairings the one who received the grape refused it until his mate was given a grape for the same job. They had unionized and both gone on protest! I love it!
Tristan Wadsworth