This is a really intersting TED lecture from pirmatologist and ethologist Frans De Waal (pictured above) that studies primate behavior. De Waal is especially interested in understanding the origins of morality, empathy, and similar emotions prevalent in species of higher order. In this particular video, De Waal is describing a simple experiment where two monkeys, housedin side-by-side cages, are rewarded with sliced cucumber for handing a researcher little rocks. The monkeys, however, prefer grapes over slices of cucumber. See what happens when one monkey is rewarded with slices of cucumbers, while another is given grapes for doing the same work!
Absolutely amazing to watch.