Interesting experiments. Not sold completely on the interpretation, but interesting regardless.
http://cosmiclog.msnbc.msn.com/_news/2012/02/20/10459741-how-monkeys-handle-moral-outrage"One of the classic studies involves capuchin monkeys who were given treats when they exchanged tokens with their human handlers. Two types of treats were offered: cucumber slices (meh...) and grapes (yum!). If one monkey saw that another monkey was consistently getting grapes while she was getting only cucumber slices, she'd quickly start protesting — by flinging the cucumber back at the handler and angrily jumping onto the cage walls.
"This is basically the Wall Street protest right here," de Waal said."
