IN the middle ages, the idea of childhood did not exist, the French historian Phillipe Aries once famously said. He was surely wrong about this, for childhood is a human universal. In Kids: How Biology and Culture Shape the Way We Raise Our Children, † Meredith F. Small, a Cornell anthropologist, sets out to popularize recent findings in her field about the evolutionary and biological underpinnings of human childhood as well as the broad cultural variations that managed to trick Aries. That she is so much more successful at the former than the latter offers a salient lesson. Hoping to encourage her readers to look more objectively at their own childrearing practices—“Other cultures teach us there are other ways to socialize, other ways to play, and other ways for kids to become moral citizens,” she explains—her own analysis unwittingly demonstrates how unlikely is an unbiased view. It seems that culture, in this case the cultural value of individualism, is as much a part of us as biology.