For example, the more of the unfolding story of history you know, the more of it you can learn. And the more ways you give that story meaning, say by connecting it to your understanding of human ambition and the untidiness of fate, the better the story stays with you. Likewise, if you’re trying to learn an abstraction, like the principle of angular momentum, it’s easier when you ground it in something concrete that you already know, like the way a figure skater’s rotation speeds up as she draws her arms to her chest.
