The Biology of Fairness Revealed

Parents of quarrelsome siblings will know that the best rule for dividing up a cake is ‘whoever cuts chooses last’. This rule uses a child’s natural self-interest to engineer a fair outcome for all. As we grow up, such cunning strategies are no longer needed: generally, we seem to see virtue in fairness for its own sake, and share the cake accordingly. But when do we develop these desirable qualities? What is it about our biology or culture that leads us to be fair? Do other animals also tend towards selfless egalitarianism? In the past few years, compelling new evidence from the fields of economics, ethology and neurobiology has begun to provide us with answers to these questions.