At some point during her development, however, she’ll exhaust the learning opportunities around bodily norms, and they’ll cease to be a fertile source of play. And soon she’ll graduate to the grown-up world, where we’re concerned mostly with social, sexual, and moral norms. These are an endless source of fascination, in part because there are so many of them, with so many nuances, that we can never hope to learn all of their boundaries and edge cases. But they’re also fascinating because they’re always shifting around as circumstances and attitudes change.