Nobody likes it when you’re paid unequally with one of your friends, colleagues, family members, etc. Whether payment means your weekly allowance or your full-time salary, being paid unequally can be the source of a lot of resentment. This is a pretty obvious statement; from a young age we, at the very least, have feelings of jealousy towards those who, perhaps, get one more cupcake than you in daycare. But what’s a more interesting question is whether us humans are the only species that react negatively to being paid unequally; i.e., whether other animals can compute fairness and react upon that.
The video above is an excerpt from Frans de Waal’s TED talk, Moral Behavior in Animals, which documents an experiment he ran that tried to answer the question above. In his case, Frans used Capuchin monkeys, one humanity’s close relatives, as his test subjects. I won’t spoil the experiment, but I will say it is a pretty hilarious result, and certainly shows that monkeys are more aware to what we would call “moral behavior” that we might have previously thought.