When your preschooler declares, “That’s not fair!” after her brother receives an imperceptibly larger piece of cake, she’s not just being selfish. Kids have a keen sense of fairness, a characteristic that research increasingly shows is an innate part of human morality. Indeed, the latest study, published in Psychological Science, finds that even babies are disturbed by displays of injustice — and even when it doesn’t apply to them.
“We found that 19- and 21-month-old infants have a general expectation of fairness, and they can apply it appropriately to different situations,” said study co-author Stephanie Sloane, a graduate student at the University of Illinois, in a statement.
In the first set of experiments, 48 babies aged 19 months were tested individually as they sat on their mothers’ laps. The infants watched a live scenario of two giraffe puppets dancing next to each other on a small stage. Suddenly, an experimenter appeared through a window at one side of the stage, saying “I have toys!” Both giraffes exclaimed, “Yay, yay!”
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