One evening while one of us (Colosi) was making dinner, her six-year-old daughter, Gianna, appeared with 10 little pieces of paper in her hand. She had been doing her homework, she said, and each of the scraps contained one of the words she was supposed to learn. When her mother asked why Gianna had torn apart her spelling list, she shrugged: “So I can do stuff with it.” For Gianna, abstract concepts became easier to understand after she had transformed them into physical objects—in this case, pieces of paper she could hold, feel and manipulate.