Dutch primatologist and ethologist Frans de Waal shows a video of two Capuchin monkeys in side-by-side cages. Each monkey is given the same task to complete: handing the experimenter a rock. Their "pay" is a slice of cucumber. But when the experimenter starts paying one of the monkeys in grapes (which the monkeys like better than cucumbers), the monkey who was being paid in cucumbers protests.
(Via 22 Words)
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects