'It's not fair' is a phrase most parents will hear from their child at some point. And new research has come out looking at just how a child's sense of fairness develops. American psychologists Peter Blake, Katherine McAuliffe and Felix Warneken studied close to nine hundred children, in seven diverse cultures. To find out if our sense of fairness is innate or learned socially. The paper is called The ontogeny of fairness in seven societies. Peter Blake is an assistant professor and the director of the Social Development and Learning Lab, at Boston University.