But we possess ugly instincts as well, and these can metastasize into evil. We are naturally kind to others, at least some of the time. We have a moral sense that enables us to judge others and that guides our compassion and condemnation. Throughout this book, I will suggest that experiments like these show that some aspects of morality come naturally to us-and others do not. The boy then leaned over and smacked the naughty puppet on the head.

As predicted, and like most toddlers in this experiment, he took it from the “naughty” one-the one who ran away with the ball. A treat was placed in front of each of them, and the boy was invited to take one of the treats away. At the end of the show, the “nice” puppet and the “naughty” puppet were brought down from the stage and set before the boy. It then rolled the ball to the puppet on the left, who ran away with it. The puppet in the middle rolled a ball to the puppet on the right, who passed it right back to him. He had just watched a puppet show with three characters. The one-year-old decided to take justice into his own hands. In the excerpt below, Bloom explores the question “What is morality?” Which, as you’ll see, is anything but child’s play. I n his new book, Just Babies: The Origins of Good and Evil, Yale psychologist Paul Bloom examines the concept of morality: its scope, its challenges, and what research into the moral lives of babies can reveal.

Just Babies by Paul Bloom