Some have said humans are vicious, selfish, and even addicted to warfare, but biologists are starting to think differently, the New York Times reports. By studying young children and comparing their behaviour with chimpanzees, they’re learning what makes us human: babies, for example, are innately sociable, and try to help others, even though animals must be selfish to survive. In a new book, called “Why We Cooperate,” Michael Tomasello, a developmental psychologist, describes how when 18-month-old infants see an unrelated adult whose hands are full trying to open a door or pick up a clothespin, they’ll try to help. The finding is not enhanced by rewards, he says, which suggests it isn’t influenced by training, and seems to occur across different cultures with different social norms. As kids grow older, they become more selective: by age 3, they’ll share with a child who’s been nice to them, for example. And even at that age, they’re willing to enforce social norms: if they learn the rules of the game, and a puppet breaks them, the children object. Tomasello believes that shared intentionality is what distinguishes people from chimpanzees: human children will use kind words and gestures to coordinate with each other, but young chimps don’t do the same. He argues this is the basis for human society, as it creates the idea of norms, and punishing those who violate them.